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GCBC Starter Kit User Manual

1. ADCReady The analog digital converter has finished a conversion CANActivity CAN bus activity is taking place CANBadMessage A bad CAN message has been received CANError Some CAN error has occured CANHighWatermark CAN high watermark reached CANRx0Ready New message present in buffer 0 CANRx1Ready New message present in buffer 1 CANRx2Ready New message present in buffer 2 CANRxReady New message present CANTxOReady Buffer 0 has been sent CANTx1Ready Buffer 1 has been sent CANTx2Ready Buffer 2 has been sent CANTxReady Sending has completed CCP1 The CCP1 module has captured an event CCP2 The CCP2 module has captured an event CCP3 The CCP3 module has captured an event CCP4 The CCP4 module has captured an event CCP5 The CCP5 module has captured an event Comp0Change The output of comparator 0 has changed Comp1Change The output of comparator 1 has changed Comp2Change The output of comparator 2 has changed Crypto The KEELOQ module has generated an interrupt EEPROMReady An EEPROM write has finished The Ethernet module has generated an interrupt This must be Ethernet dealt with in the handler ExtIntO External Interrupt pin 0 has been ed ExtInt1 External Interrupt pin 1 has been ed Extint2 External Interrupt pin 2 has been ed ExtInt3 External Interrupt pin 3 has been ed
2. KEYPAD_ROW_3 The pin on the microcontroller that connects to the Row 3 pin on the keypad N A KEYPAD_ROW_4 The pin on the microcontroller that connects to the Row 4 pin on the keypad N A KEYPAD_COL_1 The pin on the microcontroller that connects to the Col 1 pin on the keypad N A KEYPAD_COL_2 The pin on the microcontroller that connects to the Col 2 pin on the keypad N A KEYPAD_COL_3 The pin on the microcontroller that connects to the Col 3 pin on the keypad N A KEYPAD_COL_4 If using a 3 x 3 keypad do not set the KEYPAD_ROW_4 or KEYPAD_COL_4 constants The pin on the microcontroller that connects to the Col 4 pin on the keypad N A Configuration using KeypadPort When setting up the keypad code using the KeypadPort constant only KeypadPort needs to be set Constant Name Controls Default Value KeypadPort The port on the microcontroller chip that the keypad is connected to N A 65 For this to work the keypad must be connected as follows Microcontroller port pin Keypad connector 0 Row 1 1 Row 2 Row 3 Row 4 Column 1 Column 2 Column 3 NIUSA A Po Column 4 Note To use a 3 x 3 keypad in this mode the pins on the microcontroller for any unused columns must be pulled up 4 16 LCD Overview Introdu
3. Syntax SPlTransfer tx rx This command simultaneously sends and receives a byte of data using the SPI protocol It behaves differently depending on whether the PIC has been set to act as a master or a slave When operating as a master the SPIlTransfer command will initiate a transfer The data in tx will be sent to the slave whilst the byte that is buffered in the slave 71 will be read into rx In slave mode the SPITransfer command will pause the program until a transfer is initiated by the master At this point it will send the data in tx whilst reading the transmission from the master into the rx variable 4 19 GLCD Overview The GLCD commands are used to control a graphical Liquid Crystal Display based on the KS0108 driver chip These are often 128x64 pixel displays They can draw graphical elements by enabling or disabling pixels GCB makes this easier to control with the following commands Setup You must include the glcd h file at the top of your program The file needs to be in brackets include lt GLCD h gt Defines There are several connections that must be defined to use the GLCD commands with a KS0108 display The O pin is the pin on the PIC Microcontroller that is connected to that specific pin on the graphic LCD define GLCD_RW O pin Read Write pin connection define GLCD_RESET I O pin Reset pin connection define GLCD_CS1_ O pin CS1 pin connection define GLCD CS2 NO p
4. Those who are familiar with include in assembly or C should bear in mind that include in GCBASIC works differently to include in most other languages 45 code is not inserted at the location of the include but rather at the end of the current program If an appropriate File Converter is installed then include can be used to include non GCBASIC files GCBASIC will detect that the file extension of the included file matches a converter and run the appropriate converter to import the file 3 8 script Syntax script scriptcommand 1 scriptcommana2 scriptcommandn endscript Explanation The script block is used to create small sections of code which GCBASIC runs during compilation A detail explanation and example are included in the Scripts article 3 9 startup Syntax startup SubName Explanation startup is used in include files to automatically insert initialization routines Ifa define or subroutine from the file is used in the program then the specified subroutine will be called There are some limitations on this directive It may only occur once within a file and no parameters can be specified for the subroutine that is to be called 46 4 0 Advanced Features 4 1 Arrays An array is a special type of variable one which can store several values at once It is essentially a list of numbers in which each one can be addressed individually through the use of an index The index is a val
5. End If Otherwise add the character to the buffer If KeyIn gt 31 And KeyIn lt 127 Then DataCount DataCount 1 KeyLog DataCount KeyIn End If DisplayData Display key buffer LCDWriteChar is used instead of Print for greater control CLS 124 For DataPos 1 to DataCount If DataPos 17 then Locate 1 0 LCDWriteChar KeyLog DataPos Next Goto Main Interrupts About Interrupts Interrupts are a feature of many microcontrollers They allow the microcontroller to temporarily pause interrupt the code it is running and then start running another piece of code when some event occurs Once it has dealt with the event it will return to where it was and continue running the program Many events can trigger an interrupt such as a timer reaching its limit a serial message being received or a special pin on the microcontroller receiving a signal Using Interrupts There are two ways to use interrupts in GCBASIC The first way is to use the On Interrupt command This will automatically enable a given interrupt and run a particular subroutine when the interrupt occurs The other way to deal with interrupts is to create a subroutine called Interrupt GCBASIC will call this subroutine whenever an interrupt occurs and then your code can check the flag bits to determine which interrupt has occured and what should be done about it If you use this approach then you ll need to enable the desired interru
6. TestString Hello Contains Hello OtherString TestString World OtherString contains Hello World On LCD Screen Print TestString Print Hello Print OtherString Print Hello World 31 2 8 String Conversion These commands make it easy to convert String Constants and Variables to other formats 2 8 1 String to Hex The Hex function will convert a number into hexadecimal format The input number should be a byte variable or a fixed number between 0 and 255 inclusive After running the function the string variable stringvar will contain a 2 digit hexadecimal number Syntax stringvar Hex number Example Uses Hex to display as hexadecimal For CurrentLocation 0 to 255 HSerPrint Hex CurrentLocation Next 2 8 2 String to Decimal Value The Val function will extract a number from a string variable and store it in a word variable One potential use is reading numbers that are sent in ASCII format over a serial connection Syntax var Val string Example Variables for received bytes Dim DataIn As String Convert output level to numeric variable OutputLevel Val DataIn Output HPWM 1 32 OutputLevel 2 8 3 Find String within a String The Instr function will search one string to find the location of another string within it source is the string to search inside and find is the string to find The function will return the location of find within source or 0 if sour
7. 6 Main routine 7 Start 8 Turn one LED on the other off S SET PORTB 5 ON 10 Wait 1 sec 11 Now toggle the LEDs 12 SET PORTB 5 OFF 13 Wait 1 sec 14 Jump back to the start of the program 15 Goto Start 16 17 7 Click on or just press the F5 key The Great Cow Basic Compiler will convert the BlinkLED gcb file into the 1 s and O s the microcontroller within the CHIPINO modul needs to run A window will pop up showing the compile and programming of the CHIPINO was successful The LED will start to blink on the CHIPINO E GaStool V20130114 www FrankSteinberg de gt gt fst 13s lt gt gt wakeHEX bat Creat Cow BASIC 0 9 5 11 2012 piling C CCB IDE Y3 CHIPIND BLinkLED gb Program Succeeded Operation Succeeded You just successfully programmed the CHIPINO for the first time 19 1 4 Command Line Options If you are more of the technical type of user who wants to create your programs in text editor and then program via command line rather than through the IDE then GCB at the heart is a command line compiler Included here are the options for this type of programming GCBASIC O output asm A assembler P programmer K C A V L NP filename Switch Description Default O filename Sets the name of the assembly Same name as the input file generated to filename file but with a asm extension A assembler Batch file used to call The program will not be assembl
8. Explanation 3 The CLS command clears the contents of the LCD and returns te cursor to the top left corner of the screen O A Flashing Hello World program for aG s General hardware configuration MY chip 16F877A 20 Ny LCD connection sees define PRO define LCD Z PORT PORTC define aks PORTD O stan ico PORTD 1 define LCD_Enable PORTD 2 Main routine Do Print Hello World 76 Wait 1 sec CLS Wait 1 sec Loop Dim Dim has two uses both of which involve large variables It can be used to define arrays and to declare variables larger than 1 byte Syntax For Variables gt 1 byte Dim variable variable2 variable3 As type Alias othervar othervar2 At location For Arrays Dim array size At location Explanation The Dim variable command is used to inform GCBASIC of variables that are larger than 1 byte or to create alternate names for other variables The Dim array command also sets up array variables When using it for this size must be a constant value up to 80 type specifies the type of variable that is to be created Different variable types can hold values over different ranges and use different amounts of RAM See the Variables article for more information 77 When multiple variables are included on the one line GCBASIC will set them all to the type that is specified at the end of the line If there is no type specified then GCBASIC will make
9. For Bright 1 to 255 HPWM 1 40 Bright wait 10 ms next Turn down brightness over 2 5 seconds For Bright 255 to 1 HPWM 1 40 Bright wait 10 ms next loop HSerPrint HSerPrint is used to send a value over the serial connection va ue can be a string word or byte SerPrint is very similar to Print channel is the serial connection to send data through Syntax HSerPrint value Command Availability Available on all microcontrollers with a USART or UART module Note HSerPrint will not send any new line characters If the chip is sending to a terminal these commands should follow every SerPrint 99 HSerPrint 13 HSerPrint 10 Or HSerPrintCRLF Example This program will display any values received over the serial connection If pot is received the value of the analog sensor will be sent Note This has been adapted from the SerPrint example Chip settings chip 18F2525 8 config Osc Int LCD settings define LCD_IO 4 define LCD_RS PORTC 7 define LCD_RW PORTC 6 define LCD Enable PORTC 5 define LCD_DB4 PORTC 4 define LCD_DB5 PORTC 3 define LCD_DB6 PORTC 2 define LCD_DB7 PORTC 1 USART settings 100 define USART_BAUD_RATE 9600 Potentiometer define POT_PORT PORTA 0 define POT_AN ANO Set pin directions Dir SerOutPort Out Dir SerInPort In Dir POT_PORT In Create buffer variables to store received messages Dim Buffer As Str
10. HSerPrint The animal is a HSerPrint Mid TestData 5 3 Extract the action sat starts at position 9 HSerPrint The animal HSerPrint Mid TestData 9 HSerPrintCRLF 2 8 9 Retrieve String Characters Right The Right function will extract the rightmost count characters from the input string source and return them in a new string Syntax output Right source count Example Dim TestData As String TestData Hello world Display the rightmost 6 characters Will display world HSerPrint Right TestData 6 HSerPrintCRLF 2 9 Mathematical Operations If data is a calculation then it may have any of the following operands 35 add subtract or negate if there is no value before it multiply divide modulo increment decrement Bitwise and logical operators amp and or xor not equal lt gt not equal lt less than gt greater than lt less than or equal gt more than or equal The final 6 operands are for checking conditions They will return FALSE 0 if the condition is false or TRUE 255 if the condition is true The And Or Xor and Not operators function both as bitwise and logical operators GCBASIC understands order of operations If multiple operands are present they will be processed in this order Brackets Unary operations not and negate Multiply Divide Modulo Add Subtract Conditional operator
11. To use the Logic I O mode the Logic I O mode button on the upper right of the logic window must be depressed The four pins used for Logic I O digital signals pins 1 4 5 amp 6 will remain tri stated inactive until the Enable IO button is pressed Once the IO is enabled it becomes active and can be configured If no 210 valid voltage is detected on the VDD pin when clicking Enable IO a dialog will pop up to alert the user and the pins will remain disabled When the pins are enabled the pin directions and output states can be configured i PiCkit 2 Logic Tool Mode Logic I 0 Inputs Outputs Output Only g Cick Output box of press om D Oho Input D Output g 5 Input cm Input Enable 10 PICKit 2 VDD pin MUST have a valid voltage either sourced from PICKit 2 or the target or pins 4 5 amp 6 will not function Ext Logic Toot Setting Pin Direction Pins 4 5 amp 6 may be configured as Outputs output a digital signal or Inputs monitor a digital signal state connected to the pin Pin 1 is only available as an Output Click the radio buttons next to the Pin to set the pin as an Output or Input When the pin is an Input the connected signal state is displayed in the blue Inputs box Note Pin 4 and Pin 5 have a 4 7k Ohm pulldown resistor internal to the PICkit 2 This resistor is necessary for the PICkit 2 debugger functions but note that this pulldown resistor will affect an
12. Using Scripts Scripts start with script and end with endscript Inside they can consist of 3 commands elf Assignment Error If is similar to the If command in normal GCBASIC code except that it doesn t have an Else clause It is used to compare the values of constants is identical to that in GCBASIC programs The constant that is to be set goes on the left side of the and the new value goes on the right 50 Error is used to display an error message Anything after the Error command is displayed at the end of compilation and is saved in the error log for the program Example Script This script is used in the pwm h file It takes the values of the constants PWM_Freg PWM_Duty and ChipMHz and uses the equations shown in the PIC datasheets to calculate the correct values for the relevant system variables script PR2Temp int 1 PWM_Freq 4 1 ChipMHz 1000 T2PR 1 If PR2Temp gt 255 Then PR2Temp Int 1 PWM_Freq 16 1 ChipMHz 1000 T2PR 4 If PR2Temp gt 255 Then PR2Temp Int 1 PWM_Freq 64 1 ChipMHz 1000 T2PR 16 If PR2Temp gt 255 Then Error Invalid PWM Frequency value End If End If End If DutyCycle PWM_Duty 10 24 PR2Temp 1024 DutyCycleH DutyCycle AND 1020 4 DutyCycleL DutyCycle AND 3 endscript After this script has run the values PR2Temp DutyCycleH and DutyCycleL are used as constants to set up the required variables 4 6 Subrou
13. or the negative supply based on the commands in the GCB program The are various commands that can set the state of the pin GCB will attempt to determine the direction of each pin and set it appropriately However if the pin is both read from and written to during the program then the pin must be configured to input output mode by the program using the appropriate Dir command Syntax Dir port bit In Out Individual Form Dir port In Out DirectionByte Entire Port Form Explanation The Dir command is used to set the direction of the ports of the microcontroller chip The individual form sets the direction of one pin at a time whereas the entire port form will set all bits in a port This controls the TRIS register within the PIC if you are familiar with the inner workings In the individual form specify the port and bit ie PORTB 4 then the direction which is either In or Out The entire port form is similar to the TRIS instruction offered by some PIC chips To use it give the name of the port ie PORTA and then a byte is to be written into the TRIS variable This form of the command is for those who are familiar with the PIC chip s internal architecture WARNING PICs use 0 for out and 1 for in When IN and OUT are used there are no compatibility issues 21 Example This program sets PORTA bits 0 and 1 to in and the rest to out It also sets all of PORTB to output except for B1 Individual for
14. 1 microsecond 1 us 65535 us 10us 10 microseconds 10 us 2 55 ms ms 1 millisecond 1 ms 65535 ms 10ms 10 milliseconds 10 ms 2 55s s 1 second 1s 255s m 1 minute 1 min 255 min h 1 hour 1 hour 255 hours At one stage GCBASIC variables could not hold more than 255 The 10us and 10ms units were added as a way to work around this limit There is now no such limit Wait 1000 ms will work for example so these are not really needed However you may see them in some older examples or programs and the 10us units are sometimes the shortest delay that will work accurately Example This code will wait until a button is pressed then it will flash a light every half a second and produce a 440 Hz tone chip 16F819 8 config osc saine define BUTTON PORTB 0 define SPEAKER PORTB 1 define LIGHT PORTB 2 Dir BUTTON In Dir SPEAKER Out Dir LIGHT Out 187 Assumes Button switches on when pressed ll m Wait Until BUTTON i fo Wait Until BUTTON Do Flash the light Set LIGHT On Wait 500 ms Set LIGHT Off Produce the tone 440 Hz 880 changes tone on for 1 14 ms Repeat 440 PulseOut SPEAKER 1140 us Wait 114 10us Wait for 114 x 10 us 1 14 ms End Repeat Loop 188 6 0 Sample Projects Here are a few sample projects to help you get started with Great Cow Basic CHIPINO They are designed to work with the CHIPINO Demo Shield but you can build the c
15. 3 b 00000000 TempArray 4 b 00000100 TempArray 5 b 00000000 TempArray 6 b 00010001 TempArray 7 b 00010001 TempArray 8 b 00001110 Copy the character from the array to the LCD LCDCreateChar 0 TempArray 136 Draw the custom character LCDWriteChar 0 T Syntax Oy Line LineX1 LineY1 LineX2 LineY2 Optional LineColour 1 Explanation i Draws a line on a graphic LCD from X1 Y1 location to X2 Y2 location Must be horizontal or vertical Diagonal will not work ce oy Re Ld Q Syntax xX Locate ine col mn ron Explanation The Locate command is used to move the cursor on the LCD to the given location Example 137 A Hello World program for GCBASIC Uses Locate to show World on the second line General hardware configuration chip 16F877A 20 LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 oO define LCD_Enable PORTD 2 Main routine ao Print Hello P N Locate 1 5 Ae Print World Gr On Interrupt event Call handler On Interrupt event Ignore Command Availability 138 Available on PIC microcontrollers with interrupt support Explanation On Interrupt will add code to call the subroutine handler whenever the interrupt event occurs When Call is specified GCBASIC will enable the interrupt and call the interrupt handler when it
16. GPIOChange The pins on port GPIO have changed LCDReady The LCD is about to draw a segment LPWU The Low Power Wake Up has been ed 140 The external oscillator has failed and the PIC is running from Oscillatorkail an internal oscillator PMPReady A Parallel Master Port read or write has finished PORTAChange The pins on port A have changed PORTABChange The pins on port A and or B have changed PORTBChange The pins on port B have changed PSPReady A Parallel Slave Port read or write has finished PWMTimeBase The PWM time aa Teenie Time Base Period SPPReady A SPP read or write has finished SSP1Collision SSP1 has detected a bus collision SSP1Ready The ngs a ee finished sending or SSP2Collision SSP2 has detected a bus collision SSP2Ready The SSP2 MSSP2 module has finished sending or receiving Timer0Overflow Timer 0 has overflowed Timer1 Overflow Timer 1 has overflowed Timer2Overflow Timer 2 has overflowed Timer3Overflow Timer 3 has overflowed Timer4Overflow Timer 4 has overflowed Timer5CAP1 An input on the fee ane eared pad of Timer 5 to Timer5CAP2 An input on the heats Coca of Timer 5 to Timer5CAP3 An input on the geen ie Cee of Timer 5 to Timer5Match Timer5 matches the PR5 register UsartRX1Ready UART USART 1 has received data UsartRX2Ready UART US
17. Logic Tool has two operating modes 1 Logic I O Mode This mode is useful for triggering inputs to the CHIPINO and can monitor digital signals to display their state In essence it provides an alternative for wiring buttons and LEDs to pins or signals while debugging or developing I O functions 2 Logic Analyzer Mode The Analyzer mode can display waveforms of up to 3 digital signals and trigger on specific events such as a rising edge on one signal when another signal is at a logic high level This may be very useful for debugging serial communication buses such as UART SPI and 12C It is also very applicable to monitoring the behavior of general microcontroller O Logic I O Mode The PICkit 2 Logic Tool Logic I O mode is the default mode when the Logic Tool is first opened It allows simple stimulus and monitoring of digital signals The Logic Tool mode is set by the two buttons in the upper right of the Logic Tool window The 6 pin CHIPINO programming connector has 4 signal pins that can be used to inject a digital signal into a circuit or display the state of a digital signal from a circuit The remaining two pins are dedicated for Vdd and Ground connections The 6 pins can function as follows in Logic I O mode Pin Function 1 Digital Output Only VDD GND RB7 Digital Output or Digital Input RB6 Digital Output or Digital Input AUX Digital Output or Digital Input ouh WP Configuring the Logic Tool Logic I O
18. One Case 2 Print Two Case 3 Print Three Case 4 Print Four Case 5 Print Five Case Else Prit WA plot End Select Wait 250 ms Loop 169 SerPrint Syntax SerPrint channel value Explanation SerPrint is used to send a value over the serial connection va ue can be a string word or byte SerPrint is very similar to Print channel is the serial connection to send data through SerPrint will not send any new line characters If the chip is sending to a terminal these commands should follow every SerPrint SerSend channel 13 SerSend channel 10 Example This program will display any values received over the serial connection Tf pot is received the value of the analog sensor will be sent Chip settings chip 18F2525 8 config Osc Int LCD settings 170 define LCD_IO 4 define LCD_RS PORTC 7 define LCD_RW PORTC 6 define LCD_Enable PORTC 5 define LCD_DB4 PORTC 4 define LCD_DB5 PORTC 3 define LCD_DB6 PORTC 2 define LCD_DB7 PORTC 1 Serial settings define SerInPort PORTB 6 define SerOutPort PORTB 7 define SendAHigh Set SerOutPort Off define SendALow Set SerOutPort On define RecAHigh SerInPort Off define RecALow SerInPort On Potentiometer define POT_PORT PORTA 0 define POT_AN ANO Set pin directions Dir SerOutPort Out Dir SerInPort In 171 Dir POT_PORT In Create buffer variables to store r
19. PICs 10F 12F5xx 16F5xx chips Explanation When in Master mode this command will send an 12C stop condition and re enable interrupts if 12CStart disabled them In Slave mode it will re enable interrupts I2CStop should be called at the end of every 12C transmission Example Please see I2CSend and I2CReceive for an example If Then Else Syntax Short form If condition Then command Long form 112 If condition Then program code End If Using Else If condition Then code to run if true Else code to run if false End If Explanation The If command is the most common command used to make decisions If condition is true then command short or program code long will be run If it is false then the robot will skip to the code located on the next line short or after the End If long form If Else is used then the condition between If and Else will run if the condition is true and the code between Else and End If will run if the condition is false Example Turn a light on or off depending on a light sensor chip 12F683 8 113 config osc int define LIGHT GPIO 1 define SENSOR AN3 define SENSOR_PORT GPIO 4 a amp Dir SENSOR_PORT In O Do If ReadAD SENSOR gt 128 Then Set LIGHT Off 3 ao Else Set LIGHT On m End If N Loop A ps e3 S InitGLCD Explanation This initializes the Graphical LCD for operation Here are the
20. Set LIGHT Off Exit Sub End If a 3 Set LIGHT On End Sub A 5 Syntax FilledBox LineX1 LineY1 LineX2 Liag optna LineColour 1 Explanation oy Draws a filled box on a graphi D from the upper corner of X1 Y1 location to X2 Y2 location Z See also Box AO Ee Syntax For counter start To end Step increment program code Next 90 Explanation The For command is ideal for situations where a piece of code needs to be run a set number of times and where it is necessary to keep track of how many times the code has run When the For command is first executed counter is set to start Then each successive time the program loops increment is added to counter until counter is equal to end Then the program continues beyond the Next Step and increment are optional If Step is not specified GCBASIC will increment counter by 1 each time the code is run Example This code will flash a green light 6 times chip 16F88 8 config Osc Int define LED PORTB 0 Dir LED Out For LoopCounter 1 to 6 PulseOut Led 1 s Wait 1s Next 91 Syntax var Get Line Column Command Availability Sv Available on all microcontrollers except if the LCD is connected using 2 bit mode a Explanation gt The Get function reads the ASCII character a given location on the LCD QD F Syntax ad GLCDCLS No ppianation Clears the screen of a Graphic LC
21. Ss Turn on only Num Lock bit 1 PS2SetKBLeds b 00000010 oO Wait 250 ms Turn on only Caps Lock bit 2 oO PS2SetKBLeds b 00000100 Wait 250 ms Turn on only Scroll Lock bit Ay PS2SetKBLeds b 00000001 iy Wait 250 ms Ae ki No ey Syntax PS2WriteByte data Explanation 152 PS2WriteByte will send a byte to a PS 2 device Once the byte has been written the PS 2 bus will be placed in the inhibit state Example For an example please refer to the PS2SetKBLeds function in the ps2 h file PSet Syntax PSet GLCDX GLCDY GLCDState Explanation Sets or Clears a Pixel at the specified X Y location A one for GLCDState sets the pixel and a zero clears the pixel PulseOut Syntax PulseOut pin time units Explanation 153 The PulseOut command will set the specified pin high wait for the specified amount of time and then set the pin low again The pin is specified in the same way as it is for the Set command and the time is the same as for the Wait command Example This program flashes an LED on GPIO 0 using PulseOut chip 12F629 4 config INTRC_OSC_NOCLKOUT Dir GPIO 0O Out Do PulseOut GPIO 0 1 sec Turn LED on for 14sec Wait 1 sec Wait 1 sec with LED off Loop Put Syntax Put Line Column Character Explanation The Put command writes the given ASCII character code to the location on the LCD 154 Example A scrolling star for GCBASIC Mi
22. accessed using the ReadTable command The advantage of lookup tables is that they are memory efficient compared to an equivalent set of IF statements 49 Using Lookup Tables First the table must be created The code to create a lookup table is simple a line that has Table and then the name of the table a list of numbers up to 254 and then End Table Once the table is created the ReadTable command is used to read data from it The ReadTable command requires the name of the table it is to read the location of the item to retrieve and a variable to store the retrieved number in Lookup tables can store byte or word values GCBASIC will automatically detect the type of the table depending on the values in it Item 0 of a lookup table stores the size of the table If the ReadTable command attempts to read beyond the end of the table the value 0 will be returned 4 5 Scripts A script is a small section of code that Great Cow BASIC runs when it starts to compile a program Their main use is to perform calculations that are required to adjust the program for different speed chips Scripts are not compiled and downloaded to the microcontroller GCBASIC reads them runs them removes them from the program and then allows any results they have calculated to be used as constants in the program Inside a script constants are treated like variables Scripts can read the values of constants and set them to contain new values
23. and then test pin 8 to see if it changes to low indicating the switch has been pressed The LEDs are connected to pin 10 and pin 13 through 1k resistors Software switches gcb Monitor two switches and light LED when pressed Other LED lit when idle Setup for Demo Shield D8 switch controls D10 LED Chip Settings chip 16F886 4 include lt chipino h gt DIRD8in Set D8 switch pin to input DIR D10 out Set D10 LED pin to output DIR D13 out Set D13 LED pin to output Start If D8 0 Then If Left Switch Pressed set D10 on D10 LED on set D13 off D13 LED off Else set D13 on D13 LED on set D10 off D10 LED off End If Goto Start How it Works The first section is just a comment header to describes the project Each line is a comment line since it starts with an apostrophe switches gcb Monitor two switches and light LED when pressed 195 Other LED lit when idle Setup for Demo Shield D8 switch controls D10 LED The PIC16F886 in the CHIPINO is selected and then a header file with all the nicknames DO D13 and A0 A5 Chip model chip 16F 886 4 include lt chipino h gt Defines CHIPINO setup The port direction for each pin is defined The LEDs don t need this since the GCB compiler automatically sets pins to outputs but added it here to show how to setup both an input and output pin DIR D8 in Set D8 switch pin to input DIR D10 out Set D10 LED pin to output DIR D13 out
24. cc ceeeseeeeeceescseneeesesseseseesesseaaees 206 ASCII Mode a Hex Mode sepor neien eian i cod E AA A ER E E E Wrap Tentene ga E EEA ERAT aH esta EGT Log to File Clear Screen Exit UART Tool Logic Tool Logic VO Mode ccseeseeeeneeeeee Configuring the Logic Tool Logic I O Setting Pin Direction asire GM TEE aA AE ARAE Eogic Analyzer Mode iirin d h saetensssobssssecesnascoveesoucuspeoesonevenecesncbevessoneston Connecting the Analyzer es The Togie Analyzer Winde Ti erene a Y 214 Analyzer Displays AK rcn iii Analyzer Display Cursors a AtialyZer Triggers ci c2 ia inoa EE O AEEA ETO A Analyzer AgM ON rei era EE a TEEVEE RE ENE AEE EER Running the AvaghyZer csssccsseccssossssscsscssescescsnsssssccssesescescesessseesesseccnsoesasensessasaceees 1 0 Introduction Great Cow BASIC GCB is a BASIC compiler for PIC microcontrollers It lets you to program in BASIC instead of having to learn assembly or C language It s also completely open source CHIPINO is an open source development module that makes programming with Great Cow Basic Assembly or C language much easier It has the same footprint as the popular Arduino modules so all the various plug in shields that work with Arduino can work with CHIPINO CHIPINO uses a programming cable based on the open source PICkit 2 programmer from Microchip This allows the CHIPINO to be used with any blank 28 pin PIC microcontroller This also allows the user to unplug th
25. in exactly the same way as parameters for subroutines The only exception is that brackets are required around any parameters when calling a function Using Functions This program uses a function called AverageAD to take two analog readings and then make a decision based on the average Select chip chip 16F88 20 Define ports define LED PORTB 0O define Sensor ANO Set port directions dir LED out dir PORTA O in Main code Do Set PORTB 0O Off If AverageAD gt 128 Then Set PORTB 0O On wait 10 ms Loop Function AverageAD Get 2 readings divide by 2 store in AverageAD Note the cast the result of ReadAD needs to be converted to a word before adding or the result may overflow AverageAD word ReadAD Sensor ReadAD Sensor 2 end function 4 3 Interrupts Interrupts are a feature of many microcontrollers They allow the microcontroller to temporarily pause interrupt the code it is running and then start running 48 another piece of code when some event occurs Once it has dealt with the event it will return to where it was and continue running the program Many events can trigger an interrupt such as a timer reaching its limit a serial message being received or a special pin on the microcontroller receiving a signal Using Interrupts There are two ways to use interrupts in GCBASIC The first way is to use the On Interrupt command This will automatically enable a given interrupt and run
26. is very simple all that is needed is the name of the sub and then a list of parameters This code will call a subroutine named Buzz that has no parameters Buzz If the sub has parameters then they should be listed after the name of the subroutine This would be the command to call a subroutine named MoveArm that has three parameters MoveArm NewX NewY 10 If a subroutine has parameters you may choose to put brackets around them like so MoveArm NewX NewY 10 All that this does is change the appearance of the code it doesn t make any difference to what the code does Decide which one meets your own personal preference and then stick with it 52 Creating subroutines To create a subroutine is almost as simple as using one There must be a line at the start which has sub and then the name of the subroutine Also there needs to be a line at the end of the subroutine which reads end sub To create a subroutine called Buzz this is the required code sub Buzz code for the subroutine goes here end sub If the subroutine has parameters then they need to be listed after the name For example to define the MoveArm sub used above use this code sub MoveArm Armx ArmY ArmZ code for the subroutine goes here end sub In the above sub ArmX ArmY and ArmZ are all variables If the call from above is used the variables will have these values at the start of the subroutine ArmX NewX ArmY
27. no interrupts will be handled IntOff will be removed from the program if no interrupts are used It is recommended that IntOff be placed before all code that is timing sensitive in case interrupts are implemented later 126 IntOn Syntax IntOn Command Availability Available on PIC microcontrollers with interrupt support Will be automatically removed on chips without interrupts Explanation IntOn is used to enable interrupts on the microcontroller after IntOff has disabled them It should be used at the end of code which is timing sensitive IntOn will be removed from the program if no interrupts are used KeypadData Syntax var KeypadData Explanation This function will return a value corresponding to the key that is pressed on the keypad Note that if two or more keys are pressed then only one value will be returned 127 var can have one of the following values Value Constant Name Key Pressed 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 KEY_A A 11 KEY _B B 12 KEY_C C 13 KEY_D D 14 KEY_STAR Asterisk Star 15 KEY_HASH Hash 255 KEY_NONE None Example Program to show the value of the last pressed key on the LCD chip 18F4550 20 LCD connection settings 128 define LCD_IO 4 define LCD_DB4 PORTD 4 define LCD_DB5 PORTD 5 define LCD_DB6 PORTD 6
28. occurs When Ignore is specified GCBASIC will disable the interrupt handler and prevent it from being called when the event occurs If the event occurs while the handler is disabled then the handler will be called as soon as it is re enabled The only way to prevent this from happening is to manually clear the flag bit for the interrupt There are many possible interrupt events that can occur and the events vary greatly from chip to chip GCBASIC will display an error if a given chip cannot support the specified event In some cases On Interrupt will not be able to set or clear the interrupt flag and or enable bits If this is the case GCBASIC will display a warning You will need to consult the chip datasheet and use the Set command to manually set clear the flag and enable bits both at the start of the program and inside the interrupt handler subroutine If On Interrupt is used to handle an event then the Interrupt subroutine will not be called for that event However it will still be called for any events not dealt with by On Interrupt Events GCBASIG supports the events shown on the table below Some events are only implemented on a few specialized chips Events in bold are only supported by some PICs Note that GCBASIC doesn t fully support all of the hardware which can generate interrupts some work may be required with various system variables to control the unsupported peripherals 139 Event Name Description
29. portb bit 0 and play a beep on porta bit 4 until the robot is turned off chip 16F628A 4 Change this to suit your circuit define SOUNDOUT PORTA 4 define LIGHT PORTB 0 Dir LIGHT Out Do Flash Light PulseOut LIGHT ls Wait 1s Beep Gosub PlayBeep Loop PlayBeep Tone 200 10 Tone 100 10 Return 95 Goto Syntax Goto label Explanation The Goto command will make the robot jump to the line specified and continue running the program from there The Goto command is mainly useful for exiting out of loops if you need to create an infinite loop use the Do command instead Be careful how you use Goto If used too much it can make programs very hard to read To define a label put the name of the label alone on a line with just a colon after it Example This program will flash the light until the button is pressed off Notice the lab l named SWITCH_OFF chip 16F628A 4 Change this line to suit your circuit define BUTTON PORTB 0 define LIGHT PORTB 1 Dir BUTTON In Dir BUTTON Out 96 Do PulseOut LIGHT 500 ms If BUTTON 1 Then Goto SWITCH_OFF Wait 500 ms If BUTTON 1 Then Goto SWITCH_OFF Loop SWITCH_OFF Set LIGHT Off Chip will enter low power mode when program ends HPWM Syntax HPWM channel frequency duty cycle Command Availability Only available on PIC microcontrollers with Capture Compare PWM CCP module Explanation This com
30. rate window width to be pieced together For example it would be possible to collect 4 ms worth of waveform data after a trigger event at the 1 MHz sample rate Running the Analyzer Once the trigger conditions sample rate and trigger position are set as desired click the RUN button to begin collecting waveform data and looking for trigger events PICkit 2 Logic Tool Running gG Waiting for Trigger PiCkit 2 Logic Tool is waiting for a valid trigger condition To cancel abort press the PICkit2 pushbutton Do not disconnect the PICK 2 Going so may cause this application fo hang When the analyzer is running it will show the dialog above and the Busy LED on the PICkit 2 unit will be lit Once the trigger condition is met the Busy LED will turn off the Waiting for Trigger dialog will close and the analyzer waveform display will be updated with the newly captured data 220
31. shield and RS232 port on your PC or a RS232 to USB converter cable 2 Open the PICkit 2 Standalone GUI software so you can use the PICkit 2 Programming cable with the built in Terminal or Logic Analyzer See Appendix A for more detail on these features ha Open the GCB help file with details on the GCB commands and features 5 Now open the file BlinkLED GCB from the CHIPINO folder Click on E and then select the BlinkLED gcb file from the CHIPINO folder Click on Open button Look in C CHIPINO My Recent Documents Desktop My Documents My Network v 6CB_code_forPICDEMZ CON amp V_DotMatrixCode m ADC_LightSensor m ADC_Pot BlinkLED_1829 M BlinkLED_Binary BlinkLED_include BlinkKLED_PORT m CHIPING_LCD DFRobot_LCD m Dot Matrix Simple M DotMatrix DotMatrix_horizontal Um DotMatrix_TEST File name Files of type BinkLED GLCD keypad LED_Display LED_TriColor_inprogress Mary pot_servo pulseout_servo PWMTone_Doesnt_work selectcase Serial SoftPWM_dual_alternate SoftPWM_dual_together SoftPWM_Heartbeat A SoFtPWM_slow Switch_Dual GreatCowBasic gcb bas pbs h eE m Tone m Tone_wTable im Train Cancel 6 You should see the BlinkLED gcb program in the editor window 18 BlinkLED gcb gt 1 A program to flask LED on PIN 13 PORTBS 2 3 Chip model 4 chip 15F886 16 5
32. specified then the code will repeat endlessly Example This code will flash a light until the button is pressed chip 12F629 4 config osc int define BUTTON GPIO 3 define LIGHT GPIO 5 Dir BUTTON In Dir LIGHT Out Do Until BUTTON 1 84 PulseOut LIGHT 1 s Wait 1 s Loop C Syntax i End O Explanation rom When the End command is used the program will immediately stop running There are very few cases where this command is needed generally the program should be an endless loop Example oy This program JAA on the red light but not the green light End Q Set onamo Set RED On Syntax EPRead ocation store Command Availability Available on all PIC chips with EEPROM data memory Explanation EPRead is used to read information from the EEPROM data storage that many microcontroller chips are equipped with location represents the location to read data from and varies from one chip to another store is the variable in which to store the data after it has been read from EEPROM Example Program to turn a light on and off Will remember the last status chip tiny2313 1 define Button PORTB 0 define Light PORTB 1 Dir Button In Dir Light Out Load saved status EPRead 0 LightStatus If LightStatus 0 Then Set Light Off 86 Else Set Light On End If Do Wait for the button to be pressed T Wait While Button On off Toggle
33. the bit in the STATUS C location is placed into the MSB of the variable being rotated and the LSB of the variable is placed into STATUS C location When rotated left the opposite occurs The MSB of the variable is shifted to the STATUS C bit and the LSB of the variable will contain what was previously in the STATUS C bit location This table shows the operation of the Rotate Left command Command variable STATUS C Values at start b 01110011 0 Rotate Left b 11100110 0 Rotate Left again b 11001100 1 Rotate Left third time b 10011001 1 As you may notice the STATUS C bit added a 0 to the rotation So this will take 9 shifts left to get back to the original value SIMPLE option Many times you want to rotate the variable around like the STATUS C bit wasn t there so the MSB of the variable fills the LSB of the variable on Rotate Left or the LSB fills the MSB on Rotate Right That is where the SIMPLE option comes in It adds a hidden step that shifts the STATUS C bit twice so the bit moves from one end of the variable to the other Command variable STATUS C Values at start b 01110011 0 Rotate Left b 11100110 0 Rotate Left again b 11001101 1 Rotate Left third time b 10011011 1 166 Example This program will use Rotate to show a chasing LED 8 LEDs should be connected to PORTB one on each pin chip 16F819 8 config osc int Set port direction Dir PORT
34. used to start the specified timer Note that it cannot be used to start Timer 0 on a PIC this timer always runs 184 StopTimer Syntax StopTimer TimerNo Command Availability Available on all PIC microcontrollers with built in timer modules Explanation StopTimer is used to stop the specified timer Note that it cannot be used to stop Timer 0 on a PIC this timer always runs Example Please refer to the InitTimer1 article for an example Tone Syntax Tone Frequency Duration Explanation This command will produce the specified tone for the specified duration Frequency is measured in Hz and Duration is in 10 ms units 185 Please note that this command may not produce the exact frequency specified While it is accurate enough for error beeps and small pieces of monophonic music it should not be used for anything that requires a highly precise frequency Example Sample program to produce a constant A note 440 Hz on PORTB bit 1 chip 16F877A 20 define SoundOut PORTB 1 Do Tone 440 1000 Loop Wait Syntax Fixed Length Delay Wait time units Conditional Delay Wait While Until condition Explanation The Wait command will cause the program to wait for either a specified amount of time such as 1 second or while until a condition is true When using the fixed length delay there is a variety of units that are available Unit Length of unit Delay range 186 us
35. value record Wait While Button LightStatus LightStatus EPWrite 0 LightStatus N r oy Update light If LightStatus 0 Then Set Light Off i Else Set Light On NO End If ss Syntax EPWrite location data 87 Command Availability Available on all PIC chips with EEPROM data memory Explanation EPWrite is used to write information to the EEPROM data storage so that it can be accessed later by a programmer on the PC or by the EPRead command location represents the location to read data from and varies from one chip to another data is the data that is to be written to the EEPROM and can be a value or a variable Example chip 16F819 8 config osc int Set the input pin direction Dir PORTA 0O In Loop to take readings until the EEPROM is full For CurrentAddress 0 to 255 Take a reading and log it EPWrite CurrentAddress ReadAD AN0 Wait 10 minutes before getting another reading Wait 10 min Next 88 Syntax Exit Sub Explanation C O This command will make the program exit the subroutine it is Sare y in as it would if it came to the end of the subroutine O Example chip tinyl3 1 Q define SENSOR PORTB 0 P N define BUZZER PORTB 1 define LIGHT P Dir SENSOR In Dir BUZZER SNG Dir LIGHT t Fo Do Ww Burglar Loop Burglar Alarm subroutine 89 Sub Burglar If SENSOR 0 Then Set BUZZER Off
36. you must set a constant 68 Constant Name Controls Default Value Modes LCD_IO The I O mode Can 8 2 4 8 be 2 4 or 8 LCD_DB The data pin used in N A Must be set 2 2 bit mode LCD_CB The clock pin used N A Must be set 2 in 2 bit mode LCD_RS Specifies the output N A Must be set 4 8 pin that is connected to Register Select on the LCD LCD_RW Specifies the output N A Must be set 4 8 pin that is connected unless R W is to Read Write on the disabled LCD The R W pin can be disabled LCD_Enable Specifies the output N A Must be set 4 8 pin that is connected to Read Write on the LCD LCD_DATA_PORT Output port used to N A Must be set 8 only interface with LCD data bus LCD_DB4 Output pin used to N A Must be set 4 only interface with bit 4 of the LCD data bus LCD_DB5 Output pin used to N A Must be set 4 only interface with bit 5 of the LCD data bus LCD DB6 Output pin used to N A Must be set 4 only interface with bit 6 of the LCD data bus LCD_DB7 Output pin used to N A Must be set 4 only interface with bit 7 of the LCD data bus 69 The R W pin can be disabled by setting the LCD_NO_RW constant If this is done there is no need for the R W to be connected to the chip and no need for the LCD_RW constant to be set Ensure that the R W line on the LCD i
37. A reading is taken from a sensor on the slave and sent across to the master which shows the data on its LCD screen Slave Program 181 Select chip model and configuration chip 16F88 20 config MCLR_OFF Set directions of SPI pins dir PORTB 2 out dir PORTB 1 in dir PORTB 4 in Set direction of analogue pin dir PORTA O in Set SPI mode to slave SPIMode Slave Allow other PIC to initialise LCD Wait sec Main loop takes a reading and then waits to send it across do Note that rx is 0 this is because no data is to be received SPITransfer ReadAD ANO 0 loop Master Program General hardware configuration 182 chip 16F877A 20 LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD O define LCD_RW PORTD 1 define LCD_Enable PORTD 2 Set SPI pin directions dir PORTC S5 out dir PORTC 4 in dir PORTC 3 out Set SPI Mode to master with fast clock SPIMode MasterFast Main Loop do Read a byte from the slave No data to send so tx is 0 SPITransfer 0 Temp Display data if Temp gt 0 then 183 CLS Print Light LCDInt Temp Temp 0 end if Wait to allow time for the LCD to show the given value wait 100 ms loop StartTimer Syntax StartTimer TimerNo Command Availability Available on all PIC microcontrollers with built in timer modules Explanation StartTimer is
38. AD port Command Availability Available on all PIC chips with an analog to digital converter module built in Explanation ReadAD is a function that can be used to read the built in analog to digital converter that many microcontroller chips include port should be ANO AN1 AN2 etc up to the number of analog inputs available on the chip that is in use Refer to the datasheet for the microcontroller chip to find the number of ports available Note it s perfectly acceptable to use ADCx on PIC Another function ReadAD10 is almost identical to ReadAD The only difference is that it returns a full 10 bit value in a word variable 161 Example chip 16F819 8 config osc int Set the input pin direction Dir PORTA 0O In J Loop to take readings until the EEPROM is full For CurrentAddress 0 to 255 oO Take a reading and log it O EPWrite CurrentAddress ReadAD AN0 A ow Wait 10 minutes before ge another reading Next No A Wait 10 min Syntax ReadTable TableName Item Output 162 Explanation The ReadTable command is used to read information from lookup tables TableName is the name of the table that is to be read temis the line of the table to read and Output is the variable to write the retrieved value in to Itemis 1 for the first line of the table 2 for the second and so on Item 0 gives the size of the table Care must be taken to ensure that the program is not told to read
39. ART 2 has received data UsartTX1 Ready UART USART 1 is ready to send data UsartTX2Ready UART USART 2 is ready to send data USB The USB module has generated an interrupt This must be dealt with in the handler VoltageFail The input voltage has dropped too low 141 Example This program increments a counter every time Timerl overflows chip 16F877A 20 LCD connection settings define LCD_IO 4 define LCD_DB4 PORTD 4 define LCD_DB5 PORTD 5 define LCD_DB6 PORTD 6 define LCD_DB7 PORTD 7 define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 nitTimerl Osc PS1_1 8 StartTimer 1 CounterValue 0 Wait 100 ms Print Yan Test On Interrupt TimerlOverflow Call IncCounter Do CLS 142 Print CounterValue Wait 100 ms Loop Sub IncCounter CounterValue End Sub For more help see The InitTimer0 article contains an example of using Timer 0 and On Interrupt to generate a Pulse Width Modulation signal to control a motor Peek Syntax OutputVariable Peek location Explanation The Peek function is used to read information from the on chip RAM of the microcontroller location is a word variable that gives the address to read The exact range of valid values varies from chip to chip 143 This command should not normally be used as it will make the porting of code to another chip very difficult Example This program will read and check a value from PO
40. B Out Set initial state of port bits 0 and 4 on Xv PORTB b 00010001 j Chase A Do Rotate PORTB Right Simple Wait 250 ms a O Q Syntax Select can Case value code ase value2 code2 Case Else code3 167 End Select Explanation The Select Case control structure is used to select and run a particular section of code based on the value of var If var equals value then code will be run Once code has run the chip will jump to the End Select command and continue running the program If none of the other conditions are true then the code under the Case Else section will be run Case Else is optional and the program will function correctly without it If there is only one line of code after the Case the code may look neater if the line is placed after the Case This is shown below in the example for cases 3 4 and 5 It is important to note that only one section of code will be run when using Select Case Example Program to read a value from a potentiometer and display a different word based on the result chip 18F4550 20 LCD connection settings define LCD_IO 4 define LCD_DB4 PORTD 4 define LCD_DB5 PORTD 5 define LCD_DB6 PORTD 6 define LCD_DB7 PORTD 7 define LCD_RS PORTD 0 168 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 DIR PORTA O IN Do Temp ReadAD ANO 20 CLS Select Case Temp Case 0 Print None Case 1 Print
41. D 92 GLCDPrint Syntax GLCDPrint PrintLocx PrintLocY PrintData PrintLocX is the X corrdinate location for the data PrintLocY is the Y coordinate location for the data PrintData is a String or String variable of the data to display Explanation Prints string character s at a specified location on the GLCD screen On a 128x64 GLCD display X is typically 0 to 128 Y is typically 0 to 64 GLCDDrawChar Syntax GLCDDrawChar CharLocx CharLocY CharCode CharLocxX is the X corrdinate location for the character CharLocY is the Y coordinate location for the character CharCode is the ASCII number of the character to display Can be decimal hex or binary Explanation Displays an ASCII character at a specified X and Y location On a 128x64 Graphic LCD X 1 to 128 Y 1 to 64 93 Syntax GLCDWriteByte LCDByte Explanation A Writes a byte of data to the Graphic LCD memory Xv X Syntax YV GLCDWriteByte Q 8 Explanation O Reads a byte of data from the Graph LCD memory Syntax Ay Gost labo Explanation The Gosub command is used to jump to a label as a subroutine in a similar way to Goto The difference is that Return can then be used to return to the line of code after the Goto Note Gosub should not be used if it can be avoided It is not required to call a subroutine that has been defined using Sub just write the name of the subroutine Example This program will flash an LED on
42. Great Cow Basic CHIPINO penip ETO 15 _ Great Cow Basic Programming Manual Published by Electronic Products This is an online version for Personal use only Please do not copy The publisher offers special discounts on bulk orders of this book For information contact Electronic Products P O Box 251 Milford MI 48381 www elproducts com chuck elproducts com The Microchip name and logo MPLAB and PIC are registered trademarks of Microchip Technology Inc in the U S A and other countries chipKIT is a trademark of Microchip Technology Inc in the U S A and other countries All other trademarks mentioned herein are the property of their respective companies Printed in the United States of America Table of Contents 1 0 Introduction ccsssccessssssscrcessrssssrscsesscssesesssssesesscsaseesesssscsesseseseseesasessaseseecessesesses 7 1 1 Using Great Cow BasiC s aroni serisi aE i E tevsvnasovedtavestvnetsnticees 9 1 2 Using Great Cow BasiC seeen ler AE E E A VEE ETT 13 1 3 Creating your first project wee 1S 1 4 Command Line Options 2 0 Compiler Basics 2 1 Inputs Outputs 2 3 Variables 2 4 Casting wo ee 2 5 Defines Constant sissies seiri iii i ah iir M a a 2 6 Numeric Constants vis cicicteccevecsceseastaven couitetiedevsars dec riia Maiinis 2 6 1 BCD to Decimal ts 2 6 2 Decimal to BCD nssr eain a aaa Ne oteo neal hetiscdelgnassesi
43. J PICkit2GUI E aa SynWrite aan Terminal oe Ee PICPgm readme Text Document P 1il J 6kB 4 Right click on the Cow symbol to create a shortcut on your desktop D a Open Run as SynwWrite PKZIP gt Cut 3 Mail Recipient Copy E My Documents Create Shortcut 3 Bluetooth device Delete BS Netscape Messenger Rename KINGSTON urDrive 0 Properties s Removable Disk E JA DVD RW Drive F 5 You should now have a GCBC icon on your desk top 6 Installation is complete You are ready to create your first project 1 3 Creating your first project 1 Connect the Programming Cable to an open USB port 2 Connect the programming cable to the CHIPINO Make sure the red line on the cable lines up with the A arrow by the power LED on the CHIPINO 15 i ce 4 You ll see a blank screen the first time you open the IDE a f g alm i ne n BH At the top yov ll see the GCBC Toolbar for creating software projects BERR EY They represent the following functions ka Compile the GCB file and report any errors This will create a hex file 5 Compile and then program the CHIPINO through the PICkit2 Programming Cable O Open a new blank window E Open existing GCB file E Save the GCB file 2 Open a Terminal File for communication through the computer 17 serial port This requires a separate RS232
44. LCDCreateChar command is used to send a custom character to the LCD Each character on the LCD is made up from an 8 row by 5 column 5x8 matrix of pixels The data to be sent to the LCD is composed of an 8 element array where each element corresponds to a row Inside each element the 5 lowest bits make up the data for the corresponding row When a bit is set a dot will be drawn at the matching location when it is cleared no dot will appear An array of more than 8 elements may be used but only the first 8 will be read char is the ASCII value of the character to create ASCII codes 0 through 7 are usually used to store custom characters chardata is an array containing the data for the character Example This program draws a smiling face character General hardware configuration 132 chip 16F877A 20 LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 Create an array to store the character until it is copied Dim TempArray 8 Set the array to hold the character Binary has been used to improve the readability of the code but is not essential b 00011011 TempArray 1 TempArray 2 b 00011011 TempArray 3 b 00000000 TempArray 4 b 00000100 TempArray 5 b 00000000 TempArray 6 b 00010001 TempArray 7 b 00010001 TempArray 8 b 00001110 Copy the character
45. NewY ArmZ 10 When the subroutine has finished running GCBASIC will copy the values back where possible NewX will be set to ArmX and NewY to ArmY GCBASIC will not attempt to set the number 10 to ArmZ Controlling the direction data moves in It is possible to instruct GCBASIC not to copy the value back after the subroutine is called If a subroutine is defined like this sub MoveArm In ArmX In ArmY In ArmZ code for the subroutine goes here end sub Then GCBASIC will copy the values to the subroutine but will not copy them back 53 GCBASIC can also be prevented from copying the values back by adding Out before the parameter name This is used in the EEPROM reading routines there is no point copying a data value into the read subroutine so Out has been used to avoid wasting time and memory The EPRead routine is defined as Sub EPRead In Address Out Data Many older sections of code use NR at the end of the line where the parameters are specified The NR means No Return and when used has the same effect as adding In before every parameter Use of NR is not recommended as it does not give the same level of control Using different data types for parameters It is possible to use any type of variable as a parameter for a subroutine Just add As and then the data type to the end of the parameter name For example to make all of the parameters for the MoveArm subroutine word variables use this cod
46. PWM and one for Software PWM Hardware PWM requires a CCP module on the PIC chip Software PWM has no requirements regarding the PIC Hardware PWM These constants are only required for PWMOn HPWM and PWMOff do not require any constants to operate Constant Name Controls Default Value PWM_Freq Specifies the output 38 frequency of the PWM module in KHz PWM_Duty Sets the duty cycle of the 50 PWM module output Given as percentage 61 Hardware PWM is only available through the CCP 1 or CCP pin This is a hardware limitation of PIC microcontrollers Software PWM Constant Name Controls Default Value PWM_Delay The PWM Period The Not defined no delay length of any delay used will be multiplied by 255 If no value is specified no delays will be inserted into the PWM routine PWM_Outn The port physical port on Not Defined the PIC that corresponds to channel n ncan represent 1 2 3 or 4 More than 4 channels are possible but for this the PWMOut routine in include lowlevel stdbasic h must be altered 4 13 Software RS232 Overview Introduction These routines allow the microcontroller to send and receive RS232 data All functions are implemented using software so no special hardware is required on the microcontroller However if the microcontroller has a hardware serial module usually referred to as UART or USART and the serial data lines are
47. RTA Will only work on some PICs Temp PEEK S5 IF Temp 2 ON THEN SET green ON IF Temp 2 OFF THEN SET red ON Poke Syntax Poke location value Explanation The Poke command is used to write information to the on chip RAM of the microcontroller location is a word variable that gives the address to write The exact range of valid values varies from chip to chip value is the data to write to the location 144 This command should not normally be used as it will make the porting of code to another chip very difficult Example This program will set all of the PORTB pins high POKE 6 255 Pot Syntax Pot pin output Explanation Pot makes it possible to measure an analog resistance with a digital port with the addition of a small capacitor This is the required circuit 5u 470 PIC The command works by using the microcontroller pin to discharge the capacitor then measuring the time taken for the capacitor to charge again through the resistor 145 The value for the capacitor must be adjusted depending on the size of the variable resistor The charging time needs to be approximately 2 5 ms when the resistor is at its maximum value For a typical 50 k potentiometer or LDR a 50 nf capacitor is required This command should be used carefully Each time it is inserted 20 words of program memory are used on the chip which as a rough guide is more than 15 times the size of the Set comman
48. Set D13 LED pin to output Now we enter the main loop An If Else Endif command is used The first section tests if the D8 pin is low indicating the switch has been pressed If it is low then the D10 LED is lit and the D13 is shut off If D8 pin is not low then the Else section is performed and D13 LED is let and D10 is shut off The End if indicates the end of the If Else command Start If D8 0 Then If Left Switch Pressed setD100n D10 LED on set D13 off D13 LED off Else set D13 0n D13 LED on set D10 off D10 LED off End If A Goto Start command line loops back to the lable Start to make the program continuously monitor the switch input Goto Start 196 Project 3 Creating Sound Creating sound through a speaker can be very useful for a lot of projects You can create a sound when a switch is pressed or sound an alarm when the temperature drops In this project I ll show you how to make a tone through a speaker using a digital pin I ve selected a PWM pin because the demo shield is wired like that but this can be run on any digital pin The Tone command in Great Cow Basic will be used to make this a very short program to write This project will create the sound of a falling object similar to what you might hear on an old video game Drawn with Fritzing org Figure 6 3 Creating a Tone 197 Hardware The CHIPINO D5 pin will produce a square wave because it s a digital pin driving the speaker The square wave can be c
49. Syntax SPIMode Mode Command Availability Available on PIC microcontrollers with Synchronous Serial Port SSP module Explanation SPlIMode sets the mode of the SPI module within the PIC chip These are the possible SPI Modes Mode Name Description MasterSlow Master mode SPI clock is 1 64 of the frequency of the PIC Master Master mode SPI clock is 1 16 of the frequency of the PIC MasterFast Master mode SPI clock is 1 4 of the frequency of the PIC Slave Slave mode SlaveSS Slave mode with the Slave Select pin enabled 180 SPiTransfer Syntax SPlITransfer tx rx Command Availability Available on PIC microcontrollers with Synchronous Serial Port SSP module Explanation This command simultaneously sends and receives a byte of data using the SPI protocol It behaves differently depending on whether the PIC has been set to act as a master or a slave When operating as a master SPITransfer will initiate a transfer The data in tx will be sent to the slave whilst the byte that is buffered in the slave will be read into rx In slave mode the SPITransfer command will pause the program until a transfer is initiated by the master At this point it will send the data in tx whilst reading the transmission from the master into the rx variable Example There are two example programs for this command one to run on the slave PIC and one on the master
50. T 10 s Wait 10 seconds PWMOff Turn off the PWM 157 PWMoOut Syntax PWMOut channel duty cycle cycles Explanation This command uses a software PWM routine included in GCBASIC to produce a PWM signal on the selected port of the chip This routine does NOT require a PWM module on the chip channel sets the channel that the PWM is to be generated on This must have been defined previously by setting the constants SoftPWM1 SoftPWM2 etc The maximum number of channels available is 4 duty cycle specifies the PWM duty cycle and ranges from 0 to 255 255 corresponds to 100 127 to 50 63 to 25 and so on cycles is used to set the amount of PWM pulses to supply This is useful for situations in which a pulse of a specific length is required The formula for calculating the time taken for one cycle is TcycLe 28 10C Tose 255PWM_Delay where C is the number of channels used and Tosc is the length of time taken to execute 1 instruction on the chip 0 2 us on a 20 MHz chip 1 us on a 4 Mhz chip PWM_Delay is a length of time specified using the PWM_Delay constant Example This program controls the brightness of an LED on PORTB O using the software PWM routine and a potentiometer Select chip model chip 16F877A 20 Set PWM Port 158 define PWM_Out PORTB O Set port directions dir SoftPWM1 out PWM dir PORTA 0 in Potentiometer Main routine do PWMOut 1 ReadAD ANO 100 100 cycle
51. Write DataCount TimerValue_H EPWrite DataCount 1 TimerValue DataCount 2 Loop INKEY Syntax output INKEY Explanation The INKEY function will read the last pressed key from a PS 2 keyboard and return an ASCII value corresponding to the key If no key is pressed then INKEY will return 0 It will also monitor Caps Lock Num Lock and Scroll Lock keys and update the status LEDs as appropriate Example A program to accept messages from a standard PS 2 keyboard Any keys pressed will be shown on an LCD screen Hardware settings chip 18F4620 20 LCD connection settings 122 define LCD_IO 4 define LCD_DB4 PORTD 4 define LCD_DB5 PORTD 5 define LCD_DB6 PORTD 6 define LCD_DB7 PORTD 7 define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 PS 2 connection settings define PS2Clock PORTC 1 define PS2Data PORTC 0 define PS2_DELAY 10 ms Set up key log Dim KeyLog 32 DataCount 0 KeyLog 1 32 Main Read the last pressed key KeyIn INKEY If no key pressed try reading again If KeyIn 0 Then Goto Main 123 Escape pressed clear message If KeyIn 27 Then DataCount 0 For DataPos 1 to 32 eyLog DataPos 32 ext Goto DisplayData End If Backspace pressed delete last character If KeyIn 8 Then If DataCount 0 Then Goto Main KeyLog DataCount 32 DataCount DataCount 1 Goto DisplayData
52. a particular subroutine when the interrupt occurs The other way to deal with interrupts is to create a subroutine called Interrupt GCBASIC will call this subroutine whenever an interrupt occurs and then your code can check the flag bits to determine which interrupt has occured and what should be done about it If you use this approach then you ll need to enable the desired interrupts manually It is also essential that your code clears the flag bits or else the interrupt routine will be called repeatedly Some combination of these two methods is also possible the code generated by On Interrupt with check to see if the interrupt is one it recognises If the interrupt is recognised On Interrupt will deal with it if not the Interrupt subroutine will be called to deal with the interrupt The recommended way is to use On Interrupt as it is both more efficient and easier to set up During some sections of code it is desirable not to have any interrupts occur If this is the case then use the IntOff command to disable interrupts at the start of the section and IntOn to re enable them at the end If any interrupt events occur while interrupts are disabled then they will be processed as soon as interrupts are re enabled If the program does not use interrupts IntOn and IntOff will be removed automatically by GCBASIC 4 4 Lookup Tables A lookup table is a list of values that are stored in the program memory of the chip which can be
53. al display may be selected highlighted with the cursor and copied into the clipboard by right clicking and selecting Copy or pressing lt Ctrl gt lt C gt 207 Hex Mode The UART Tool Hex mode displays the hex values of bytes received from the CHIPINO in the terminal display A line of bytes received by the UART Tool is preceded with the text RX A line of bytes transmitted by the UART Tool is preceded with the text TX In Hex mode bytes may only be transmitted one way by typing a sequence of one or more hex values in one of the four Send Hex Sequences boxes To send a sequence click Send next to it A hex sequence may contain from 1 to 48 bytes The Echo On checkbox has no function in Hex mode Data in the terminal display may be selected highlighted with the cursor and copied into the clipboard by right clicking and selecting Copy or pressing lt Ctrl gt lt C gt Wrap Text This checkbox affects both modes ASCII and HEX When checked a displayed line will automatically wrap at the right edge of the terminal display If unchecked then a received line will not wrap and a horizontal scroll bar will appear in the terminal display to allow the entire line to be viewed The terminal display will keep the last 200 lines of received data in the buffer The vertical scroll bar may be used to view previous data or text Log to File The Log to File button allows all text and data to be saved to a text file a
54. als but only a small window of time At lower sample rates we can see a longer window of elapsed time but at less detail and may miss fast pulses Generally the sample rate should be set at least 10 times the highest frequency or 5 times the fastest pulse width to get a decent representation of the waveform Any waveform that has frequency higher than half the sample rate may alias Aliasing means that waveform edges are missed and so the waveform can appear slower than it actually is Of course the sample rate can always be set slower than these limits if all that s desired is to get a general idea of what s going on in the circuit without much detail 218 SUPPORTED SAMPLE RATES Time Between Waveform Limitations Sample Rate Samples Captured Waveform Length Maximum Frequency 1024 samples _ before aliasing 4 MHz Aus 1ms 500 kHz 500 kHz 2us 2ms 250 kHz 250 kHz 4us 4 1 ms 125 kHz 100 kHz 10 us 10 2 ms 50 kHz 50 kHz 20 us 20 5 ms 25 kHz 25 kHz 40 us A ms 12 5 kHz 10 kHz 100 us 102 4 ms 5 kHz 5 kHz 200 us 204 8 ms 2 5 kHz Note 1 Waveform length is rounded to the nearest 0 1 decimal place Trigger Position Changing the trigger position allows more flexibility over how the captured data relates to the trigger event For example we might be more interested in what happened before the trigger rather than after There are 6 selectable trigger positions Start of Data This
55. and one in each of several include files However care must then be taken to ensure that the settings in one file do not conflict with those in another 23 2 3 Variables A variable is an area of memory on the microcontroller that can be used to store a number or a series of letters This is useful for many purposes such as taking a sensor reading and acting on it or counting the number of times the robot has performed a particular task Each variable must be given a name such as MyVariable or PieCounter Choosing a name for a variable is easy just don t include spaces or any symbols other than _ and make sure that the name is at least 2 characters letters and or numbers long Variable Types There are several different types of variable and each type can store a different sort of information These are the variable types that Great Cow BASIC can currently use Variable type Information that this Example uses for this type of variable can store variable Bit A bit 0 or 1 Flags to track whether or not a piece of code has run Byte A whole number between 0 General purpose storage of and 255 data such as counters Word A whole number between 0 Storage of extra large numbers and 65535 Integer A whole number between Anything where a negative 32768 and 32767 number will occur Long A whole number between 0 Storing very very big numbers and 2 32 4 29 billion Array A list of whole numbers Log
56. and then convert the result to a word to store in MyWord Suppose that ByteVar is 150 and AnotherByteVar is 231 When added this will come to 381 which will overflow leaving 125 in the result However when the cast is added GCBASIC will treat ByteVar as if it were a word and so will use the word addition code This will cause the correct result to be calculated Often a cast will be used when calculating an average MyAverage word Valuel Value2 2 It s also possible to cast the second value MyAverage Valuel word Value2 2 The result will be exactly the same 2 5 Defines Constants Syntax define Find Replace 28 Explanation define will search through the program for Find and replace it with the value given for Replace A define or constant is a type of directive that tells the compiler to find a given word and replace it with another word or number Defines are useful for situations where a routine needs to be easily altered For example a define could be used to specify the amount of time to run an alarm for once triggered It is also possible to use defines to specify ports thus defines can be used to aid in the creation of code that can easily be adapted to run on a different PIC with different ports GCBASIC makes considerable use of defines internally For instance the LCD code uses defines to set the ports that it must use to communicate with the LCD Using Defines To create a define i
57. ayeands QF Steins Constants 0 sessnsssacssencusescssotansssces vate is aena eA Mgucstoreesotecsetcnsetesevessonseseees 2 8 String Conversion s 2 8 1 Strime tO Hexen pM aad a a A oboe 2 8 2 String to Decimal Value cccccsceeceSMbpecepectessssescsscsesessosssonessssessssenssessoneee 32 2 8 3 Find String within a String oy 2 84 Convert to Lower Cassiere cicer E aineina aiia 33 2 8 5 Convert to Upper Caseira sii A SE EE EAE EEEE 33 2 8 6 Convert Number to String 34 2 8 7 Retrieve String Characters Left 34 2 8 8 Retrieve String Characters Middle 35 2 8 9 Retrieve String Characters Right 35 2 9 Mathematical Operations 139 2 10 Conditions ieee eee ie dT 2 11 Combining Multiple Instructions 0 0 0 ccc cece eceeeeseseesceesesesssscsseesesseseeeseees 38 2 12 COMME NES soe ponani a n e a iora 39 3 0 Directives ase SEO iT o Aas pessonsucensneanisss sve utes vedconergetignessuabvndsoxs usdupcaahenees case set E BD HCOMMS Myre We RE E E E E E E 3 6 ifndef 3 7 include ORE aT o A E E E EES E E E less cdesieoveee 3 9 startup 4 2 Functions 4 3 Interrupts sii 4 A L ok p Tables zisne i ER A En E E EE AEE EE AEE EREE 49 AS SCTIPUS ae eR AA E ENE EE PEE EE VATA RERE E E VEERE KESEN EARE 4 6 Subroutines 4T PS2 Keypad OVerViEW nre teher Astr parE e EE EA Er E e Lor r EESE RE EE Ee a 55 4 8 Random Overview sievcseccccvssersesccvecsevecevecasveservence
58. beyond the end of the table or strange effects will be observed The type of Output should match the type of data stored in the table For example if the table contains Word values then Output should be a Word variable If the type does not match GCBASIC will attempt to convert the value Example Chip Settings chip 16F88 20 Hardware Settings define LED PORTB 0 Dir LED Out Main Routine ReadTabl TimesTwelve 4 Temp Set LED Off If Temp 48 Then Set LED On Lookup table named TimesTwelve Table TimesTwelve 12 163 24 36 48 60 72 84 96 108 120 132 144 End Table Repeat Syntax Repeat times program code End Repeat Explanation The Repeat command is ideal for situations where a piece of code needs to be run a set number of times It uses less memory and runs faster than the For 164 command and should be used wherever it is not necessary to count how many times the code has run Example This code will flash a green light 6 times chip 16F88 20 define LED PORTB 0 dir LED out Repeat 6 PulseOut LED 1 s Wait 1s End Repeat Rotate Syntax Rotate variable Left Right Simple Explanation The Rotate command will rotate variable one bit in a specified direction The bit shifted will be placed in the Carry bit of the Status register STATUS C STATUS C acts as a ninth bit of the variable that is being rotated 165 When a variable is rotated right
59. bit random number When compiling a program GCBASIC will generate an initial seed for the generator However this seed will be the same every time the program runs so the sequence of numbers produced by a given program will always be the same To work around this there is a Randomize subroutine It can be provided with a new seed for the generator which will cause the generator to move to a different point in the sequence Alternatively Randomize can be set to obtain a seed from some other source such as a timer every time it is run 56 Relevant Constants These constants are used to control settings for the tone generation routines To set them place a line in the main program file that uses define to assign a value to the particular constant Constant Name Controls Default Value RANDOMIZE_SEED Source of the random TimerO seed if Randomize is called without a parameter 4 9 12C Overview Introduction These routines allow GCBASIC programs to send and receive I2C messages They can be configured to act as master or slave and the speed can also be altered No hardware 12C module is required for these routines all communication is handled in software However these routines will not work on 12 bit instruction PICs 10F 12F5xx and 16F5xx chips Relevant Constants These constants control the setup of the software I2C routines Constant Con
60. ce does not contain find Syntax 32 location nstr source find Example Dim TestData As String TestData Hello world Display the location of world within the string Will return 8 because w in world is the 8th character of Hello world HSerPrint Instr TestData world HSerPrintCRLF Display the location of planet within the string Will display 0 because planet does not occur inside the string Hello world HSerPrint Instr TestData planet HSerPrintCRLF 2 8 4 Convert to Lower Case The LCase function will convert all of the letters in the string source to lower case and return the result Syntax output LCase source Example Set chip model chip 16F1936 Set up hardware serial connection define USART_BAUD_RATE 9600 define USART_BLOCKING Fill a string with a message Dim TestData As String TestData Hello world Display the string in lower case Will display hello world HSerPrint LCase TestData HSerPrintCRLF 2 8 5 Convert to Upper Case The UCase function will convert all of the letters in the string source to upper case and return the result 33 Syntax output UCase source Example Dim TestData As String TestData Hello world Display the string in upper case Will display HELLO WORLD HSerPrint UCase TestData 2 8 6 Convert Number to String The Str function will convert a number into a string number can be an
61. communication 205 UART Tool Window To open the PICkit 2 UART Tool window select Tools gt UART Tool The PICkit 2 Programmer window will open and the PICkit 2 Programmer application window will close as the programmer cannot be used while the UART Tool is active and vice versa The UART Tool has two modes ASCII and HEX The current mode is selected by the buttons on the upper right hand of the display The button corresponding to the active mode will be displayed depressed The mode selection affects how serial data is displayed and entered in the window and the modes are explained in the next two sections s m Ni 2 PICkit 2 UART Tool Pf RX 0 4p 53 41 TX 70 6B 32 a Target Send Hex Sequences F Wino Text ART Choul ce veo Oda 70 5t Lagta Ala Fens H j Laka E Qesr Screen f ax re Connect Pi 2 VDD isast VDO Sen BR UASI loot Setting the Baud Rate and Connecting The baud rate may be selected from the combo box in the upper left corner of the UART Tool window Several common baud rates are listed and by selecting Custom any baud rate from 150 to 38400 in 1 baud increments may be used 206 O00000 N OODQDQDO e Owona kMN 2 1 2 F 4 5 9 1 3 i a ASCII Mode When ASCII mode is selected serial bytes received from the CHIPINO are displayed as ASCII characters in the main window terminal display All bytes are displayed consecutively To di
62. connected to the appropriate pins the hardware routines should be used for smaller code improved reliability and higher baud rates 62 Relevant Constants These constants are used to control settings for the RS232 serial communication routines To set them place a line in the main program file that uses define to assign a value to the particular constant Constant Name s Controls Default Value SendALow SendBLow SendCLow These are used to define the commands used to send a low 0 bit on serial channels A B and C respectively nop must be set SendAHigh SendBHigh SendCHigh These are used to define the commands used to send a high 1 bit on serial channels A B and C respectively nop must be set RecALow RecBLow RecCLow The condition that is true when a low bit is being received Sys232Temp 0 OFF must be set RecAHigh RecBHigh RecCHigh The condition that is true when a high bit is being received Sys232Temp 0 ON must be set 4 14 Hardware RS232 Overview Introduction These subroutines allow GCBASIC programs to communicate more easily using RS232 These hardware based routines are intended for use on microcontrollers with built in RS232 modules normally referred to in datasheets as USART or UART modules To use these the RS232 data lines must be connected to the pins on the microcontroller used by the serial mod
63. ction The routines in this section allow GCBASIC programs to interact with alphanumeric Liquid Crystal Displays based on the HD44780 IC This covers most 16 x 2 and similar displays These routines allow the displays to be connected to the microcontroller in many different ways Connection Mode Required Connections 0 None are required directly by the routines However the LCD routines must be provided with other subroutines which will handle the communication This is useful for communicating with LCDs connected through RS232 or 12C 2 Data and Clock lines This mode is used when the LCD is connected through a 74LS174 shift register IC as detailed at http www rentron com Myke1 htm 66 4 R W RS Enable and the highest 4 data lines DB4 through DB7 8 R W RS Enable and all 8 data lines The data lines must all be connected to the same I O port in sequential order For example DBO to PORTB O DB1 to PORTB 1 and so on with DB7 going to PORTB 7 Using 0 bit mode To use 0 bit connection mode a subroutine to write a byte to the LCD must be provided Optionally another subroutine to read a byte from the LCD can also be given If there is no way to read from the LCD then the LCD _NO RW constant must be set In 0 bit mode the LCD_RS constant will be set automatically to a spare bit variable The higher level LCD commands such as Print and Locate will set it and the co
64. d pin is the port connected to the circuit The direction of the pin will be dealt with by the Pot command output is the name of the variable that will receive the value Example This program will beep whenever a shadow is detected A potentiometer is used to adjust the threshold chip 16F628A 4 config INTOSC_OSC_NOCLKOUT define ADJUST PORTB 0 define LDR PORTB 1 define SoundOut PORTB 2 Dir SoundOut Out Do Pot ADJUST Threshold Pot LDR LightLevel If LightLevel gt Threshold Then Tone 1000 100 End If Loop 146 Print Syntax Print string Print byte Print word Print integer Explanation The Print command will show the contents of a variable on the LCD It can display string word or byte variables Example A Light Meter program General hardware configuration chip 16F877A y 20 define LightSensor ANO LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 147 define LCD_Enable PORTD 2 CLS Print Light Meter Locate 1 2 Print A GCBASIC Demo n cS Do A CLS Print Light Level Print ReadAD LightSensor Q Wait 250 ms oe Ld N a Ry oa Command Availability Available on all PIC chips with self write capability Explanation 148 ProgramErase erases information from the program memory on chips that support this feature The largest value p
65. de responsible for writing to the LCD should read it and then set the RS pin on the LCD appropriately This code is an example of how to use 0 bit mode It sends messages to another microcontroller which has been programmed to read the messages and toggle the pins of an LCD appropriately define LCD_IO 0 define LCDWriteByte MySendToLCD define LCD_NO_RW Sub MySendToLCD In MyLCDByte Uses I2C Sends an address byte 128 Then a control byte where bit 4 is the state of the RS pin Then a data byte which is sent to the LCD data pins 67 ControlByte 0 f LCD_RS On Then ControlByte 4 On 2CStart 2CSend 128 2CSend ControlByte 2CSend MyLCDByte 2CStop Need to allow time for receiver of message to update LCD Wait 5 ms End Sub If the LCD was to be read then LCDReadByte would be set to the name of a function that reads the LCD and returns the data byte from the LCD Relevant Constants Note this section does not apply in 0 bit mode These constants are used to control settings for the Liquid Crystal Display routines included with GCBASIC To set them place a line in the main program file that uses define to assign a value to the particular constant Some constants are used required for 4 and 8 bit modes some are required for 4 bit mode and some are used by 8 bit mode When using 2 bit mode only three constants must be set all others can be ignored Check the Modes column to determine if
66. define LCD_DB7 PORTD 7 define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 Keypad connection settings define KeypadPort PORTB Main loop Do Get key Temp KeypadData If a key is pressed then display it If Temp lt gt KEY NONE Then CLS Print Temp Wait 100 ms End If Loop 129 KeypadRaw Syntax largevar KeypadRaw Explanation This function will return a 16 bit value in which each bit corresponds to a key on the keypad If the key is pressed its bit will hold 1 and if it is released its bit will contain a 0 This table shows the key that each bit corresponds to Bit Key Position row col Common Key Symbol 15 1 1 1 14 1 2 2 13 1 3 3 12 1 4 A 11 2 1 4 10 2 2 5 9 2 3 6 8 2 4 B 7 3 1 7 6 3 2 8 5 3 3 9 4 3 4 C 3 4 1 2 4 2 0 1 4 3 0 4 4 130 Example Program to show the keypad status using LEDs chip 16F877A 20 Keypad connection settings define KeypadPort PORTB LEDS define LED1 PORTC define LED2 PORTD Dir LED1 Out Dir LED2 Out Declare a 16 bit variable for the key value Dim KeyStatus As Word Main loop Do Get key eyStatus KeypadRaw Display LED1 KeyStatus_H High Byte LED2 KeyStatus Low Byte Loop 131 LCDCreateChar Syntax LCDCreateChar char chardata Explanation The
67. e sub MoveArm ArmX As Word ArmY As Word ArmZ As Word end sub Optional parameters Sometimes the same value may be used over and over again for a parameter except in a particular case If this occurs a default value may be specified for the parameter and then a value for that parameter only needs to be given in a call if it is different to the default For example suppose a subroutine to create an error beep is required Normally it emits a 440 Hz tone but sometimes a different tone is required To create the sub this code would be used Sub ErrorBeep Optional OutTone As Word 440 Tone OutTone 100 End Sub Note the Optional before the parameter and the 440 after it This tells GCBASIC that if no parameter is supplied then set the OutTone parameter to 440 If called using this line ErrorBeep then a 440 Hz beep will be emitted If called using this line 54 ErrorBeep 1000 then the sub will produce a 1000 Hz tone When using several parameters it is possible to make any number of them optional If the optional parameter s are at the end of the call then no value needs to be specified If they are at the start or in the middle then you must insert commas to allow GCBASIC to tell where the optional parameters are Overloading It is possible to have 2 subroutines with the same name but different parameters This is known as overloading and GCBASIC will automatically select the most appropriate subrout
68. e are number 0 thru 7 If Var 2 1 then Test bit 3 of variable Var to see if its set to 1 Set D13 on Light LED on D13 if it s set End If Setting Variables Syntax Variable data 25 Explanation Variable will be set to data Data can be either a fixed value such as 157 another variable or a sum If data is a fixed value it must be an integer between 0 and 255 inclusive If data is a calculation then it may have any of the following operands add subtract or negate if there is no value before it multiply divide modulo amp and or xor not equal lt gt not equal lt less than gt greater than lt less than or equal gt morethan or equal 26 The final 6 operands are for checking conditions They will return FALSE 0 if the condition is false or TRUE 255 if the condition is true The And Or Xor and Not operators function both as bitwise and logical operators GCBASIC understands order of operations If multiple operands are present they will be processed in this order 1 Brackets 2 Unary operations not and negate 3 Multiply Divide Modulo 4 Add Subtract 5 Conditional operators 6 And Or Xor There are several modes in which variables can be set GCBASIC will automatically use a different mode for each calculation depending on the type of variable being set If a byte variable is being set byte mode will be used if a wo
69. e chip and build it into a permanent design when the software is complete This makes the combination of Great Cow Basic and CHIPINO a perfect development platform for creating electronic products Great Cow BASIC has been written with three main aims to remove the need for repetitive assembly commands to produce efficient code and to make it easy to take code written for one chip and run it on another It hides many of the more confusing parts of microcontroller programming making it suitable for beginners and those who don t like assembly or C It s also great for kids to learn electronic programming And aren t we all just kids inside The syntax of Great Cow BASIC is based on that of QBASIC FreeBASIC but with some alterations to suit the vastly different system that makes up a microcontroller Great Cow BASIC will allow you to program most 8 bit PIC microcontrollers PIC10F 12F 16F and 18F chips Features e Standard BASIC flow control statements If Select Case Do For Goto e Support for multiply divide add subtract boolean operations and comparisons e Bit Byte Word and String data types in addition to byte arrays e Subroutines and Functions e Inline assembly in most cases without any special directives e Data tables Portable reusable code e Supports most 8 bit PIC microcontrollers e Write code fora PIC1OF 12F 16F or 18F 8 bit PIC Microcontroller e Automatically recalculates all delay commands dependi
70. e monitored by an Analog pin on the CHIPINO In this case though we ll just light an LED when it s dark and turn it off when there is light Drawn with Fritzing org Figure 6 4 Creating a Tone Hardware One side of the light sensor is connected to ground The other connects to the resistor and also the analog pin 1 The pull up resistor is a 10k connected to 5v You may have to adjust the resistor for your light sensor but in most cases a 10k will work fine In the dark the photo resistor has a high resistance and in the light it has a low resistance Therefore in the dark the voltage will be high and in the light the voltage will be low 200 The LED controlled by the sensor is connected to pin 10 of the digital port A 220 ohm series resistor connected to the anode and the cathode connected to ground completes the circuit Software light gcb This program monitors a photoresistor connected to the AN1 pin If it s in the dark it will light the LED on D13 If it s in the light then LED is shutoff Written for the CHIPINO Demo Shield Chip Settings chip 16F886 4 include lt chipino h gt Dir A1 In Make Analog 1 pin input Dir D13 out Make D15 pin output Start Do Light LED if in the dark If ReadAD A1 lt 150 Then set D13 on Sensor is Dark else set D13 off Bright light on sensor end if Loop How it Works The first section is just a comment header to describes the project Each line i
71. e window By selecting zoom level 0 5x the waveform is compressed so 2 samples are shown per pixel which allows the entire waveform to be view at once but with a loss of detail Zoom levels 2x and 4x display the waveform with 2 pixels per sample and 4 pixels per sample respectively This allows relative time details between the waveforms to be more easily seen Save Waveform Click the Save button to save the current waveform display in a bitmap file The time scale will be added to the bottom of the display If cursors are active the cursors and their times will also be saved with the display Analyzer Display Cursors The display cursors are useful for making time and frequency measurements in the displayed waveform Click to check the Cursors checkbox and enable the cursors Enable Disable Time difference from Time delta between cursors Cursors ws r cursor to trigger period frequency 50 us f Div V Cursos X 116 us Y 135 us Y X 19 us 52 63 kHz 1 Oe pA 1 2o0om Ch O 05x Ix Ch2 2x ch3 mat lt f N gt Save X Cursor Y Cursor Left click mouse Right click mouse Place the X cursor by left clicking in the waveform display Place the Y cursor by right clicking in the waveform display It can be helpful to use Zoom for exact placement of the cursors When zoomed the cursors will get wider as they are the width of a sample and the sample width grows with increasing zoom Above t
72. eceived messages Dim Buffer As String Dim OldBuffer As String BufferSize 0 Set up serial connection InitSer 1 r9600 1 WaitForStart 8 1 none Show test messages Print Serial Tester Wait 1s SerPrint 1 GCBASIC RS232 Test SerSend 1 13 SerSend 1 10 Wait 1s Main loop Do Get a byte from the terminal SerReceive 1 Temp invert If Enter key was pressed deal with buffer contents If Temp 13 Then 172 Buffer 0 BufferSize Try to execute commands in buffer If Not ExecCommand Buffer Then Show message on bottom line last message on top CLS Print OldBuffer Locate 1 0 Print Buffer Store the message for next time OldBuffer Buffer End If BufferSize 0 End If Backspace code delete last character in buffer If Temp Then If BufferSize gt 0 Then BufferSize 1 BAd If Received ASCII code between 32 and 127 add to buffer If Temp gt 32 And Temp lt 127 Then BufferSize 1 Buffer BufferSize Temp 173 End If Loop Takes a sensor reading and sends it to terminal Sub SendSensorReading SerPrint 1 Sensor Reading SerPrint 1 ReadAD10 POT_AN SerSend 1 13 SerSend 1 10 End Sub Will check the buffer for a command If command found run it and return true If not return false Function ExecCommand CmdIn As String ExecCommand False If received command is pot show potentiometer value If CmdIn pot Then SendSen
73. en several displays are multiplexed To set up the routines in this way the displays must be connected as follows Microcontroller port pin Display Segment 0 1 B 2 C 3 D 4 E 5 F 6 G 4 12 PWM Overview Introduction The routines described in this chapter allow the generation of Pulse Width Modulation signals These allow for the microcontroller to control the speed of a 60 motor or the brightness of a light The routines can also be used to generate the appropriate frequency signal to drive an infrared LED for remote control applications The PWMOn PWMOff and HPWM routines use the PWM generation module on the microcontroller They will only work on some microcontrollers see the article on each command for details PWMOn and HPWM will cause the PWM module on the microcontroller to start generating the PWM signal which will then continue to be generated until the PWMOff instruction is run PWMOtut does not make use of any special hardware However a signal is only generated while the PWMOut command is running when the program moves on to the next command the signal will stop Relevant Constants These constants are used to control settings for the Pulse Width Modulation module of the PIC chip To set them place a line in the main program file that uses define to assign a value to the particular constant Note that there are two sets of constants one for Hardware
74. er If A GCASM is assembled given GCBASIC will use its internal assembler P programmer Batch file used to call The program will not be programmer This parameter is downloaded ignored if the program is not assembled K C A Keep original code in assembly No original code left in output K C will save comments output K A will preserve all input code N Verbose mode compiler gives None more detailed information about its activities L Show license and exit None NP Do not pause on errors Use with Pause when an error IDEs occurs and wait for the user to press a key filename The file to compile None For the A and P switches there are special options available If YFILENAME is present it will be replaced by the name of the asm file If SFN_NOEXT will be replaced by the name of the asm file but without an extension and CHIPMODEL will be replaced with the name of the chip The name of the chip will be the same as that on the chip data file 20 2 0 Compiler Basics 2 1 Inputs Outputs Most general purpose pins on a microcontroller can function in one of two modes input mode or output mode When acting as an input the pin will be placed in high impedance state The microcontroller will then sense the pin and the program can read the state of the pin and make decisions based on it When in output mode the microcontroller will connect the pin to either Vcc the positive supply or Vss ground
75. erSend 1 Temp Wait 100 ms Loop Set Syntax Set variable bit On Off Explanation The purpose of the Set command is to turn individuals bits on and off The Set command is most useful for controlling output ports but can also be used to set variables Often when controlling output ports Set is used in conjunction with constants This makes it easier to adapt the program for a new circuit later 177 Example Blink LED sample program for GCBASIC Controls an LED on PORTB bit 0 Set chip model and config options chip 16F84A 20 Set a constant to represent the output port define LED PORTB 0 Set pin direction Dir LED Out Main routine Do Set LED On Wait 1 sec Set LED OFF Wait A s c Loop 178 ShortTone Syntax ShortTone Frequency Duration Explanation This command will produce the specified tone for the specified duration Frequency is measured in units of 10 Hz and Duration is in 1 ms units Please note that this command may not produce the exact frequency specified While it is accurate enough for error beeps and small pieces of monophonic music it should not be used for anything that requires a highly precise frequency Example Sample program to produce a tone on PORTB bit 1 based on the reading of an LDR on ANO usually PORTA bit 0 chip 16F88 20 define SoundQut PORTB 1 Dir PORTA 0O In ShortTone ReadAD ANO 100 Loop 179 SPIiMode
76. erecosscessevsseioVedeoVeldussceoesehesssovereodete 56 4 9 I2C Overview 57 4 10 Timer Overview 58 4 11 Seven Segment Overview 58 4 12 PWM Overview ceeeee 60 4 13 Software RS232 Overview 62 4 14 Hardware RS232 Overview a063 415 Keypad OvervieWns rendano iie aa ea i Ae 64 4 16 LCD OVERVIEW oresoao Ri EER teeta adousabevmgenl footy is 4 17 Tone Overview 4 18 SPL OVErVICW veciv ccsvesccssasvessveenscvscesvecesevetvenssdedisvecesvescosestsessesesesvece E DisplayChar DisplayValue GLCDCLS GLCDPrint me GLEDDraw har vsicices cavessbevdavede sarn E E EAE NEIEN a EEDI ire zR E E A E N A R GLCDReadByte HSerPrint HSerReceive HSerSetid vais cccsvccsseccascssavesscscevsscnveesvencavexevexesvaserveiscoderecovsdvssesesssh edeo erce ecavexdieesie eveeds IPA RECEIVE EE aceite lis eRe Ces ees Fe POSE tl DEAE CBT ae 12CSend 12CStart I2CStop If Then Else InitGLCD InitSer InitTimer0 InitTimer1 INKEY Interrupts IntOff ProgramErase ProgramRead ProgramWrite PS2ReadByte PS2SetKBLeds PS2WriteByte SPI Transfer StartTimer sls STOP TAMER TS AEAEE E EE ATASE A TEE TOME 5 50235 E AAEE A E A A E E S E EA Project 1 Train Crossing Project 2 Sensing a Switch Project 3 Creating Sound Connecting the UART Tool m UART Tool Window sess srorceriannuririnnuninenn an a en Setting the Baud Rate and Connecting 00
77. form capture of a 2 byte transmission and details the elements of the display window section 0 5x Trigger Time Scale Division Line Waveform Scroll Waveform Save Zoom Level Waveform Trigger The trigger is a pre defined event inthe monitored signals that causes a capture of the signal waveform Triggeringis discussed in detail in section 3 2 2 The Analyzer Trigger Section On the waveform display the point where the trigger occurred is indicated by a vertical red line The trigger was set to occur at the first rising edge of Channel 1 in the SPI SCLK clock signal above Time Scale Above left of the waveform display is the time scale This is how much time each Division Line in the waveform represents Each division is 50 microseconds of time in the picture Division Line A division line is a gray vertical line across the waveform display which can be used to give a time reference to the displayed waveform Smaller hash marks at the top and bottom of the display subdivide each time division into 5 smaller units Waveform Scroll The captured waveform is longer than can be shown all at once effectively in the display so the horizontal scroll bar allows the display to scroll for viewing the entire waveform 215 Waveform Zoom Level The waveform Zoom allows 4 levels of zoom to be selected Normally at 1x zoom each sample of a waveform is displayed as a pixel A waveform is 1024 pixels of which 500 can be displayed in th
78. from the array to the LCD LCDCreateChar 0 TempArray 133 Draw the custom character LCDWriteChar 0 LCDHex Syntax LCDHex value Explanation The LCDHex command will show the specified value on the LCD at the current cursor position It will convert the byte it has been given into hexadecimal format Example A program to count ftom to FF on an LCD screen General hardware configuration chip 16F877A gt 20 LCDr connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 134 define LCD_Enable PORTD 2 For Counter 0 To 255 CLS LCDHex Counter Wait 250 ms ext LCDWriteChar Syntax LCDWriteChar char Explanation The LCDWriteChar command will show the specified character on the LCD at the current cursor position char is the ASCII value of the character to show On most LCDs characters 0 through 7 are user defined and can be set using the LCDCreateChar command Example This program draws a smiling face character General hardware configuration 135 chip 16F877A 20 LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 Create an array to store the character until it is copied Dim TempArray 8 Set the array to hold the character TempArray 1 b 00011011 TempArray 2 b 00011011 TempArray
79. gital Converter ADC 22 0 EEPROM UART SPI 12C hardware Timers And more PIC16F886 The Connections to the programmer are shown in the picture below The CHIPINO modules take care of all these connections for you but you can build it your self in a breadboard as shown PICIGF amp 86 MCLRIVpp PIC Programmer 4 ICSP Connector Vdd Vss opona RB7 PGD RB6 PGC to circuit 100 100 In Circuit Serial Programming ICSP 12 PIC in a Breadboard 1 2 Using Great Cow Basic The Great Cow Basic compiler can be downloaded from the greatcowbasic com website as a complete software package Installation instructions are below Installation Requirements Windows PC running XP or higher or Mac running Parallels Windows Linux running Wine USB Port There are two ways to install Great Cow Basic CHIPINO GCBC on your PC Automatic Installation or Manual Installation Automatic Installation 1 Download the GCBC Setup file and run it on your computer It will install GCBC in your start menu and also place an icon on your desktop 13 Manual Installation 1 If available you can also download the GCBCIDEVx zip file from the greatcowbasic com website 2 Unzip it to a directory on your computer i o GCBC GCBC 3 Open the GCBCIDEVXx folder and you ll see several folders i _Demos i _MyFiles CJ CHIPINO G G Stools an GreatCowBasic i PicKit2 C
80. he waveform display the time difference between the Trigger and each cursor is displayed along with the difference between the triggers The time period between the cursor is also displayed as the related frequency 216 Analyzer Trigger The trigger is a user defined set of events in the monitored signals that causes the capture of a waveform Each channel can be assigned one of the following trigger events Trigger Trigger when Chi 2 DontCare 1 Logic High Ch2 1 0 LogicLow Rising Edge Ch3 Ml Faling Edge occurs 4 times ff 256 ox Don t Care The analyzer channel is ignored for triggering purposes 1 Logic High The channel must be at a logic high state to trigger 0 Logic Low The channel must be at a logic low state to trigger Rising Edge The channel must transition from low to high states to trigger V Rising Edge The channel must transition from high to low states to trigger It s best to set just one trigger at a time but if you set trigger events on all channels they must happen all at once in order for the trigger to activate data capture For example These settings will trigger on the rising edge of Channel 1 Ch 1 rising edge Ch 2 ignore Ch 3 ignore These settings with trigger on the rising edge of Channel 1 and Channel 2 ata high level Ch 1 rising edge Ch 2 1 logic high Ch 3 ignore It is also pos
81. igh bits even where the number of high bits must always be even or none for systems that do not use parity invert can be either normal or invert If it in invert then high bits will be changed to low and low to high Example Please refer to SerSend for an example of InitSer 116 InitTimerO Syntax InitTimerO source prescaler Command Availability Available on all microcontrollers with a Timer 0 module Explanation InitTimerO will set up timer 0 according to the settings given source can be Osc or Ext On a PIC microcontroller prescaler can be one of the following settings PSO_2 PSO_4 PS0 8 ePS0_16 ePS0_32 PS0 64 ePS0_128 ePS0_256 These correspond to a prescaler of between 1 2 and 1 256 the oscillator speed The prescaler will apply to either the oscillator or the external clock input 117 When the timer overflows from 255 to 0 a TimerOOverflow interrupt will be generated This can be used in conjunction with On Interrupt to run a section of code periodically Example This code will use Timer 0 and On Interrupt to generate a Pulse Width Modulation signal that will allow the speed of a motor to be easily controlled chip 16F88 8 config osc int define MOTOR PORTB 0 Call the initialisation routine InitMotorControl Main routine Do Increase speed to full over 2 5 seconds For Speed 0 to 100 MotorSpeed Speed Wait 25 ms Next H
82. in CS2 pin connection define GLCD RS I O pin RS pin connection define GLCD_ENABLE O pin Enable pin Connection define GLCD_DBO NO pin Data pin 0 Connection define GLCD_DB1 NO pin Data pin 1 Connection define GLCD_DB2 N pin Data pin 2 Connection define GLCD_DB3 N pin Data pin 3 Connection define GLCD_DB4 NO pin Data pin 4 Connection define GLCD_DB5 N pin Data pin 5 Connection define GLCD_DB6 O pin Data pin 6 Connection define GLCD_DB7 NO pin Data pin 7 Connection 72 Commands InitGLCD Initialize port pins GLCDCLS Clear screen GLCDPrint In PrintLocX In PrintLocY PrintData As String GLCDDrawChar In CharLocx In CharLocY In CharCode Box In LineX1 In LineY1 In LineX2 In LineY2 Optional In LineColour 1 FilledBox In LineX1 In LineY1 In LineX2 In LineY2 Optional In LineColour 1 Line In LineX1 In LineY1 In LineX2 In LineY2 Optional In LineColour 1 PSet In GLCDX In GLCDY In GLCDState GLCDWriteByte In LCDByte GLCDReadByte 73 5 0 Commands Box Syntax Box LineX1 LineY1 LineX2 LineY2 Optional LineColour 1 Explanation Draws a box on a graphic LCD from the upper corner of X1 Y1 location to X2 Y2 location See also FilledBox command ClearTimer Syntax ClearTimer TimerNo Explanation ClearTimer is used to clear the specified timer Example Please refer to the InitTimer1 article for an example 75 Syntax CLS
83. ine for each call An example of this is the Print routine in the LCD routines There are actually 3 Print subroutines one has a byte parameter one a word parameter and one a string parameter If this command is used Print 100 Then the Print byte subroutine will be called However if this command is used Print 30112 Then the Print word subroutine will be called If there is no exact match for a particular call GCBASIC will use the option that requires the least conversion of variable types For example if this command is used Print PORTB O The byte print will be used This is because byte is the closest type to the single bit parameter 4 7 PS2 Keypad Overview Introduction These routines make it easier to communicate with a PS 2 device particularly a keyboard 55 Relevant Constants These constants affect the operation of the PS 2 routines Constant Name Controls Default Value PS2Data Pin connected to PS 2 N A data line PS2Clock Pin connected to PS 2 N A clock line PS2_DELAY This constant can be set Not set to a delay such as 10 ms If set a delay will be added at the end of every byte sent or received 4 8 Random Overview Introduction These routines allow GCBASIC to generate pseudo random numbers The generator uses a 16 bit linear feedback shift register to produce pseudo random numbers The most significant 8 bits of the LFSR are used to provide an 8
84. ing Dim OldBuffer As String BufferSize 0 Show test messages Print Serial Tester Wait 1s HSerPrint GCBASIC RS232 Test HSerSend 13 HSerSend 10 Wait 1s Main loop 101 Do Get a byte from the terminal HSerReceive Temp If Enter key was pressed deal with buffer contents If Temp 13 Then Buffer 0 BufferSize Try to execute commands in buffer If Not ExecCommand Buffer Then Show message on bottom line last message on top CLS Print OldBuffer Locate 1 0 Print Buffer Store the message for next time OldBuffer Buffer End If BufferSize 0 End If Backspace code delete last character in buffer If Temp 8 Then If BufferSize gt 0 Then BufferSize 1 End If 102 Received ASCII code between 32 and 127 add to buffer If Temp gt 32 And Temp lt 127 Then BufferSize 1 Buffer BufferSize Temp End If Loop Takes a sensor reading and sends it to terminal Sub SendSensorReading HSerPrint Sensor Reading HSerPrint ReadAD10 POT_AN HSerSend 13 HSerSend 10 End Sub Will check the buffer for a command If command found run it and return true If not return false Function ExecCommand CmdIn As String ExecCommand False If received command is pot show potentiometer value Ife mdIn pot Then SendSensorReading ExecCommand True End If End Function 103 HSerReceive Syntax Used as subroutine HSerRecei
85. ing the Analyzer The CHIPINO programming connector pins 4 5 amp 6 are used as the inputs for the three logic channels There are holes in the board where you can solder a header for connecting to the Logic Analyzer or you can route signals to the B7 and B6 pins to display the signal 213 E Cursos X 116 us Y 135 us Y X 19 us 52 63 kHz Zoom Pin Function MCLR VDD GND B7 Channel 1 B6 Channel 2 AUX Channel 3 onahWNM For example to monitor a SPI bus the analyzer channel pins could be connected to monitor the three main bus signals as follows Logic Analyzer Pin SPI Bus Signal Channel 1 SCK bus master clock Channel 2 SDO bus master output Channel 3 SDI bus master input Note Pin 4 and Pin 5 have a 4 7k Ohm pulldown resistor internal This resistor is necessary for the debugger functions but note that this pulldown resistor will affect any digital signal these pins are connected to The Logic Analyzer Window The Logic Tool analyzer window is divided into 3 sections These include 1 Display for viewing and measuring captured waveforms 2 Trigger for setting trigger conditions for a capture 214 3 Acquisition for setting the waveform sample rate and the waveform relation to the trigger sample Analyzer Display The display section of the analyzer window allows the waveform to be viewed zoomed measured and saved as a bitmap file Below is a SPI bus wave
86. ircuits separately if you know how to do that CHIPINO Demo Shield Project 1 Train Crossing Flashing an LED is a great place to start but let s put it to some practical use Have you ever stopped at a train crossing and seen the red lights flash back and forth to indicate a train is coming This can be accomplished real easy with two LEDs This project can also be built into a model train railroad crossing sign to make it a little more realistic Hardware There are two LEDs to control The LEDs are driven on by a high signal on the digital pin that drives them A low shuts them off A resistor is placed in series with the LEDs to limit the current A 1k ohm resistor works fine The left LED is connected to the digital pin number 13 on the CHIPINO The right LED is connected to pin 10 A series resistor is used to limit the current and any value from 220 ohms to 1k ohms can be used Both LEDs are red on the CHIPINO demo shield 190 Drawn with Fritzing org Figure 6 1 Train Crossing Project Software Train gcb A program to flash two red LEDs like a train crossing on Digital pins 10 and 13 red LEDs on Demo Shield Chip model chip 16F886 4 include lt chipino h gt Defines CHIPINO setup Main routine Start Turn one LED on the other off setD100n Left LED on set D13 off Right LED off wait 1 sec 191 Now toggle the LEDs Set D10 OFF Left LED off Set D13 ON right LED on wa
87. is the trigger position used in all the prior Figure waveforms All the waveform data except for one division is captured after the trigger occurs This is best used when all the waveform data of interest happens after the trigger Center of Data This is best used when all the waveform data of interest happens around the trigger The trigger event is in the middle of the waveform display End of Data All the waveform data except for just over one division is captured prior to the trigger occurs This is best used when all the waveform data of interest happens before the trigger Delay 1 Window Delay 2 Windows Delay 3 Windows In these cases the trigger position is considered Start of Data but the waveform capture is delayed 1000 samples nearly one waveform display after the trigger This allows a user to capture events that occur further out than the display width after a trigger happens without reducing the sample rate In other words when Delay 1 Window is selected the analyzer will wait 1000 samples after the trigger event occurs before it begins recording waveform data When Delay 2 Windows is selected it will wait 2000 samples etc 219 Each waveform display is 1024 samples so the 1000 sample delay increment gives a small overlap between successive delay captures Assuming that the data of interest after the trigger is repeatable and consistent this allows a total waveform of up to 4 times the sample
88. it 1 sec Jump back to the start of the program goto Start How it Works The first section is just a comment header to describes the project Each line is a comment line since it starts with an apostrophe Train gcb A program to flash two red LEDs like a train crossing on Digital pins 10 and 13 red LEDs on Demo Shield The PIC16F886 in the CHIPINO is selected and then a header file with all the nicknames DO D13 and A0 A5 Chip model chip 16F886 4 include lt chipino h gt Defines CHIPINO setup The main loop controls the two separate LEDs by controlling the digital pins they are connected to Setting pin D13 off and pin D10 on lights the left LED A wait command for 1 second creates the flash rate The second section does the opposite and lights the right LED on pin D13 and shuts off the left LED on pin D10 Another wait of 1 second is added Main routine Start Turn one LED on the other off setD100n Left LED on set D13 off Right LED off wait 1 sec Now toggle the LEDs 192 Set D10 OFF Left LED off Set D13 ON right LED on wait 1 sec The program stays in a continuous loop with the goto Start command line creating an alternating lighting of the LEDs to create the train crossing display Jump back to the start of the program goto Start 193 Project 2 Sensing a Switch On many projects you will need some kind of human interface to control the operation A momentary pu
89. l speed Explanation The chip directive is used to specify the chip model and speed that GCBASIC must compile for model is the model of the microcontroller chip something along the lines of 16F819 speed is the speed of the chip in MHz and is required for the delay and PWM routines If speed is omitted GCBASIC will use the highest clock speed that the internal oscillator can support If the chip does not have an internal oscillator then GCBASIC will assume that the chip is being run at its maximum possible clock speed using an external crystal Examples chip 12F509 4 chip 18F4550 48 chip 16F88 0 125 chip tiny2313 1 chip mega8 16 3 2 config Syntax config option option2 optionn Explanation The config directive is used to specify configuration options for the chip There is a detailed explanation of config in the Configuration section of help 3 3 define Syntax define Find Replace 41 Explanation define will search through the program for Find and replace it with the value given for Replace 3 4 if Syntax if Condition endif Explanation The if directive is used to prevent a section of code from compiling unless Condition is true Condition has the same syntax as the condition in a normal GCBASIC if command The only difference is that it uses constants instead of variables Example This program will pulse an adjustable number of pins on PORTB The number of pi
90. l it when you need it Function DecToBed va as Byte DecToBcd va 10 16 va 10 End Function Example BCDNumber DecToBcd number Convert variable number to BCD value 2 6 2 Decimal to BCD Sometimes you need to convert numbers from Binary Coded Decimal format to decimal GCB doesn t have the function built in but you can easily add it with this function below Just add this to your GCB program and then call it when you need it 30 Function BcdToDec va as byte BcdToDec va 16 10 va 16 End Function Example DecNumber BcdToDec number Convert variable number to Decimal value 2 7 String Constants String variables are useful for many communication commands such as send to an LCD Strings are characters placed between quotes If a variable is set equal to a string the ASCII value equivalent will be used A will read as the ASCII value of 65 d will read as the ASCII value of 100 Strings can be combined in a single phrase within quotes For example The string Hello is the same as H e P P o Here is how strings can be useful for sending letters to an LED display This program will show Hello on a LED display The display is connected to PORTB Dim Message As string Message Hello For Counter 1 to 6 DisplayChar 1 Message Counter Wait 250 ms Next You can also combine strings like variables Dim TestString as string DIM OtherString as string
91. le define Blinkl ifdef Blinkl PulseOut PORTB 0O 1 sec Wait I sec endif ifdef Blink2 PulseOut PORTB 1 1 sec Wait 1 sec endif This code will pulse PORTB O but not PORTB 1 This is because Blink1 has been defined but Blink2 has not If the line define Blink2 was added at the start of the program then both pins would be pulsed The value of the constant defined is not important and can be left off of the define 43 Enabling code if a constant is defined and has a given value Syntax Example define PinsToFlash 2 ifdef PinsToFlash 1 2 3 PulseOut PORTB 0O 1 sec endif ifdef PinsToFlash 2 3 PulseOut PORTB 1 1 sec endif ifdef PinsToFlash 3 PulseOut PORTB 2 1 sec endif This program uses a constant called PinsToFlash that controls how many lights are pulsed PORTB 0O is pulsed when PinsToFlash is equal to 1 2 or 3 PORTB 1 is pulsed when PinsToFlash equals 2 or 3 and PORTB 2 is flashed when PinsToFlash is 3 Enabling code if a system variable is defined Syntax Example ifdef NoVar ANSEL SET ADCON1 PCFG3 OFF SET ADCON1 PCFG2 ON SET ADCON1 PCFG1 ON SET ADCON1 PCFGO OFF endif ifdef Var ANSEL ANSEL 0 endif The above section of code has been copied directly from a d h It is used to disable the A D function of pins so that they can be used as standard digital I O ports If ANSEL is not declared as a system variable for a particular chip then the program uses ADCON1 to cont
92. m is used for PORTA DIR PORTA O IN DIR PORTA 1 IN DIR PORTA 2 OUT DIR PORTA 3 OUT DIR PORTA 4 OUT DIR PORTA 5 OUT DIR PORTA 6 OUT DIR PORTA 7 OUT Entire port form used for B DIR PORTB b 00000010 Entire port form used for C DIR PORTC IN 2 2 Configuration Every PIC chip has a CONFIG word This is an area of memory on the chip that stores settings which govern the operation of the chip The following aspects of the chip are governed by the CONFIG word Oscillator selection will the chip run from an internal oscillator or is an external one attached eAutomatic resets should the chip reset if the power drops too low If it detects it is running the same piece of code over and over Code protection what areas of memory must be kept hidden once written to ePin usage which pins are available for programming resetting the chip or emitting PWM signals The exact configuration settings vary amongst chips To find out a list of valid settings please consult the datasheet for the PIC chip that you wish to use This can all be rather confusing hence GCB will automatically set some config settings unless told otherwise eLow Voltage Programming LVP is turned off This enables the PGM pin usually B3 or B4 to be used as a normal I O pin 22 eWatchdog Timer WDT is turned off The WDT resets the chip if it runs the same piece of code over and over this can cause trouble with some of the longer delay r
93. mand sets up the hardware PWM module of the PIC chip to generate a PWM waveform of the given frequency and duty cycle Once this command is called the PWM will be emitted until PWMOff is called If you only need one particular frequency and duty cycle you should use PWMOn and the constants PWM_Freg and PWM_Duty instead 97 channel is 1 or 2 and corresponds to the pins CCP1 and CCP2 respectively On chips with only one CCP port pin CCP or CCP1 is always used and channel is ignored It should be set to 1 anyway to allow for future upgrades to more powerful PIC chips frequency sets the frequency of the PWM output It is measured in KHz The maximum value allowed is 255 KHz The minimum value varies depending on the clock speed 1 KHz is the minimum on chips 16 MHz or under and 2 Khz is the lowest possible on 20 MHz chips In situations that do not require a specific PWM frequency the PWM frequency should equal approximately 1 five hundredth the clock speed of the PIC ie 40 Khz on a 20 MHz chip 16 KHz on an 8 MHz chip This gives the best duty cycle resolution possible duty cycle specifies the desired duty cycle of the PWM signal and ranges from 0 to 255 where 255 is 100 duty cycle Example This program will alter the brightness of an LED using hardware PWM Select chip model and speed chip 16F877A 20 Set the CCP1 pin to output mode DIR PORTC 2 out Main code 98 do Turn up brightness over 2 5 seconds
94. n 81 This command will display the given value on a seven segment LED display display is the number of the display to use and data is the value between 0 and 9 to show Example This program will count from 0 to 99 on two LED displays chip 16F819 8 config osc int define DISP_SEG_A PORTB 0 define DISP_SEG_B PORTB 1 define DISP_SEG_C PORTB 2 define DISP_SEG_D PORTB 3 define DISP_SEG_E PORTB 4 define DISP_SEG_F PORTB 5 define DISP_SEG_G PORTB 6 define DISP_SEL_1 PORTA 0 define DISP_SEL 2 PORTA 1 Do For Counter 0 To 99 Get the 2 digits Number Counter Numi 0 82 If Number gt 10 Then Numl Number 10 SysCalcTempX stores remainder after division Number SysCalcTempxX End If Num2 Number Show the digits Q Each DisplayValue will erase the other ioitspteningy Y So they must be called often enough that the f ing cannot be seen oO Repeat 500 DisplayValue 1 Numl 1 Wait 1 ms Ay O DisplayValue 2 Num2 Ay Wait 1 ms oy End Repeat A Next NG 88 Q s Syntax Do While Until condition 83 program code Loop While Until condition Explanation The Do command will cause the code between the Do and the Loop to run repeatedly while condition is true or until condition is true depending on whether While or Until has been specified Note that the While or Until and the condition can only be specified once or not at all If they are not
95. n 255 so we need to define a word variable we named SND short for sound Word variables will hold a number up to 65 535 GCB automatically creates byte variables when you use a variable but for larger than a byte size you need to define it using the DIM command line DIM SND as word Create a word variable Now we enter the main loop A For Next command is used to create the sound producing loop It starts by setting the SND variable to 2000 and then steps down by 5 each loop until SND equals 200 Then Tone command is used to produce the tone in the speaker It produces a frequency in the speaker equal to the value of the SND variable It starts with a 2000 hertz tone and slowly drops down to 200 hertz The speed is set by how long each tone lasts and then is controlled by the value in the Tone command line In this case its set to produce a tone for 10 milliseconds each Start For SND 2000 to 200 step 5 Tone SND 1 Tone with 10 msec delay Next The For Next loop automatically continuously loops but we add a Goto Start at the bottom just in case the software gets lost and has to get back to the beginning Goto Start 199 Project 4 Sensing Light We can use a photo resistor to sense light using an analog pin A photo resistor changes resistance as it is exposed to light By putting a pull up resistor connected to 5v in series with the photo resistor changing light will create a variable voltage The variable voltage can then b
96. ng on the clock speed of the chip I O capabilities e Standard 2x16 LCD routines e Routines for on chip A D PWM SPI USART EEPROM and Timers e RS232 communications rates between 300 and 19200 bps with user configurable parity start and stop bits e PS 2 keyboard reading e 4x4 Keypad Other features e Extensive help file and forum e Several translations e Generates standard MPASM compatible assembly code for PIC e Free both in the free beer way and the free speech way e Open Source Great Cow Basic is created by a group of key contributors including Program Contributors Hugh Considine Main developer of Great Cow Basic Stefano Bonomi Two wire LCD subroutines Geordie Millar Swap and Swap4 subroutines Finn Stokes 8 bit multiply routine program memory access code Translation Contributors We only support English in this manual Stefano Delfiore Italian Pablo Curvelo Spanish Murat Inceer Turkish Other Contributors Russ Hensel Great Cow BASIC Notes Chuck Hellebuyck This manual Frank Steinberg GCB SYN IDE for Great Cow Basic Alexy T SynWrite IDE used for GCB IDE 1 1 Using Great Cow Basic The best way to start using Great Cow Basic is with a complete starter kit You can get the CHIPINO module Great Cow Basic software for Windows USB Programmer cable CHIPINO module sample software projects and this ebook manual in pdf form in one complete starter package Benip Lee 15 With
97. ns is controlled by the FlashPins constant chip 16F88 8 The number of pins to flash define FlashPins 2 Initialise Dir PORTB Out Main loop Do if FlashPins gt 1 PulseOut PORTB 0 250 ms endif if FlashPins gt 2 PulseOut PORTB 1 250 ms endif if FlashPins gt 3 PulseOut PORTB 2 250 ms endif if FlashPins gt 4 PulseOut PORTB 3 250 ms endif Loop 42 3 5 ifdef Syntax ifdef Constant Constant Value Var VariableName endif Explanation The ifdef directive is used to selectively enable sections of code There are several ways in which it can be used eChecking if a constant is defined eChecking if a constant is defined and has a particular value eChecking if a system variable exists Checking if a system bit has been defined The advantage of using ifdef rather than an equivalent series of IF statements is the amount of code that is downloaded to the chip ifdef controls what code is compiled and downloaded IF controls what is run once on the chip ifdef should be used whenever the value of a constant is to be checked GCBASIC also supports the ifndef directive this is the opposite of the ifdef directive it will remove code that ifdef leaves and vice versa Note The code in the following sections will not compile as it is missing chip directives and DIR commands It is intended to act as an example only Enabling code if a constant is defined Syntax Examp
98. old speed Wait 1s 118 Decrease speed to zero over 2 5 seconds For Speed 100 to 0 MotorSpeed Speed Wait 25 ms Next Hold speed Wait 1s Loop Setup routine Sub InitMotorControl Clear variables MotorSpeed 0 PWMCounter Il fo Add a handler for the interrupt On Interrupt Timer0Overflow Call PWMHandler Set up thea ttuter InitTimer0 Osc PS0_1 2 Timer 0 starts automatically on a PIC End Sub PWM sub This will be called when Timer 0 overflows 119 Sub PWMHandler If MotorSpeed gt PWMCounter Then Set MOTOR On Else Set MOTOR Off End If PWMCounter 1 If PWMCounter 100 Then PWMCounter 0 End Sub InitTimer1 Syntax InitTimer1 source prescaler Command Availability Available on all microcontrollers with a Timer 1 module Explanation InitTimer1 will set up timer 1 according to the settings given source can be Osc Ext or ExtOsc ExtOsc is only available on PIC microcontrollers On a PIC prescaler can be one of the following settings ePS1_1 ePS1_2 120 PS1_4 ePS1_8 Example This example will measure that time that a switch stays on for chip 16F819 20 define Switch PORTA 0 Dir Switch In DataCount 0 InitTimer Osc PS1_8 Dim TimerValue As Word Do ClearTimer 1 Wait Until Switch On StartTimer 1 Wait Until Switch off StopTimer 1 Read the timer TimerValue Timerl Log the timer value 121 EP
99. om the receiver before continuing If in master mode 2CSend will send the data immediately If in slave mode 12CSend will wait for the master to request the data before sending Example This program will act as an I2C analog to digital converter When data is requested from address 83 registers 0 through 109 3 it will return the value of ANO through AN3 Chip model chip 16F88 8 I2C settings define I2C_MODE Slave define I2C_CLOCK PORTB 0 define I2C_DATA PORTB 1 Main loop Do Wait for start condition I2CStart Get address I2CReceive Address If Address 83 Then If addressswas this device s address respond I2CReceiv Register OutValue ReadAD Register I2CSend OutValue End If 110 I2CStop Wait 5 ms Loop 12CStart Syntax l2CStart Command Availability Available on all microcontrollers except 12 bit instruction PICs 10F 12F5xx 16F5xx chips Explanation If the 12C routines are operating in Master mode this command will send a start condition If routines are in Slave mode it will pause the program until a start condition is sent by the master It should be placed at the start of every 12C transmission If interrupt handling is enabled this command will disable it Example Please see I2CSend and I2CReceive for an example 111 12CStop Syntax I2CStop Command Availability Available on all microcontrollers except 12 bit instruction
100. onverted into a semi rounded signal to work better with the speaker by placing a 10 uf capacitor in series between pin 5 and the speaker s positive lead The other side of the speaker is then grounded An 8 ohm speaker works fine but a more common approach is a piezo speaker A Piezo speaker from Jameco com under part number DBX05 PN will work well The setup is shown in Figure 6 3 The right side of the capacitor is the positive side and that connects to the digital pin D5 The speaker positive is also on the right side and connects to the negative side of the capacitor The speaker is then grounded to the ground pin on the CHIPINO power header Software tone gcb This program produces a falling sound on Digital Pin 5 connected to Piezo speaker on Demo Shield chip 16F886 4 include lt chipino h gt DIM SND as word Create a word variable define SoundOut D5 Start For SND 2000 to 200 step 5 Tone SND 1 Tone with 10 msec delay Next goto start How it Works The first section is just a comment header to describes the project Each line is a comment line since it starts with an apostrophe tone gcb This program produces a falling sound on Digital Pin 5 connected to Piezo speaker on Demo Shield The PIC16F886 in the CHIPINO is selected and then a header file with all the nicknames DO D13 and A0 A5 198 chip 16F 886 4 include lt chipino h gt The tone command will use a value larger tha
101. ossible for location depends on the amount of program memory on the PIC which is given on the datasheet This command must be called before writing to a block of memory It is slow in comparison to other GCBASIC commands Note that is erases memory in 32 byte blocks see the relevant PIC datasheet for more information This is an advanced command which should only be used by advanced developers Care must be taken with this command as it can easily erase the program that is running on the PIC ProgramRead Syntax ProgramRead ocation store Command Availability Available on all PIC chips with self write capability Explanation ProgramRead reads information from the program memory on chips that support this feature location and store are both word variables meaning that they can store values over 255 The largest value possible for location depends on the amount of program memory on the PIC which is given on the datasheet store is 14 bits wide and thus can store values up to 16383 This is an advanced command which should only be used by advanced developers 149 ProgramWrite Syntax ProgramWrite location value Command Availability Available on all PIC chips with self write capability Explanation ProgramWrite writes information to the program memory on chips that support this feature location and value are both word variables The largest value possible for location depends on the amount of p
102. outines in GCBASIC Master Clear MCLR is disabled where possible On many newer chips this allows the MCLR pin often PORTA 5 to be used as a standard input port It also removes the need for a pull up resistor on the MCLR pin eAn oscillator mode will be selected based on the following rules in this order of priority 1 If the PIC has an internal oscillator and the internal oscillator is capable of generating the speed specified in the chip line then the internal oscillator will be used 2 If the clock speed is over 4 Mhz the external HS oscillator is selected 3 If the clock speed is 4 MHz or less then the external XT oscillator mode is selected Note that these settings can be individually overridden whenever needed For example if the Watchdog Timer is needed adding the line below will enable the watchdog timer without affecting any other configuration settings config WDT ON Using Configuration Once the necessary CONFIG options have been determined adding them to the program is easy On a new line type config and then list the desired options separated by commas such as in this line config OSC RC BODEN OFF GCB also supports this format on 10 12 16 series chips config INTOSC_OSC_NOCLKOUT BODEN_OFF However for upwards compatibility with 18F chips you should use the first config settings option It is possible to have several config lines in a program for instance one in the main program
103. pts manually It is also essential that your code clears the flag bits or else the interrupt routine will be called repeatedly Some combination of these two methods is also possible the code generated by On Interrupt with check to see if the interrupt is one it recognises If the interrupt is recognised On Interrupt will deal with it if not the Interrupt subroutine will be called to deal with the interrupt 125 The recommended way is to use On Interrupt as it is both more efficient and easier to set up During some sections of code it is desirable not to have any interrupts occur If this is the case then use the IntOff command to disable interrupts at the start of the section and IntOn to re enable them at the end If any interrupt events occur while interrupts are disabled then they will be processed as soon as interrupts are re enabled If the program does not use interrupts IntOn and IntOff will be removed automatically by GCBASIC IntOff Syntax IntOff Command Availability Available on PIC microcontrollers with interrupt support Will be automatically removed on chips without interrupts Explanation IntOff is used to disable interrupts on the microcontroller It should be used at the start of code whichis timing sensitive and which would not function correctly if paused and restarted It is essential that IntOn is used to turn interrupts on again after the timing sensitive code has finished running If not
104. rd variable is being set word mode will be used If a byte is being set but the calculation involves numbers larger than 255 word mode can be used by adding WORD to the start of one of the values in the calculation This is known as casting If you prefer you can add LET to the start of the line It will not alter the execution of the program but is included for those who are used to including it in other BASIC dialects Example This program is to illustrate the setting of variables Chipmunk 46 Sets the variable Chipmunk to 46 Animal Chipmunk Sets the variable Animal to the value of the variable Chipmunk 27 Bear 2 3 5 Sets the variable Bear to the result of 2 3 5 17 Sheep 2 3 5 Sets the variable Sheep to the result of 2 3 5 25 Animal 2 Bear Sets the variable Animal to twice the value of Bear LargeVar 321 LargeVar must be set as a word see DIM Temp LargeVar WORD 5 Note the use of WORD to ensure that the calculation is performed correctly 2 4 Casting Casting changes the type of a variable or value Placing the type that the value should be converted to in square brackets will tell the compiler to convert it For example this will cause two byte variables to be treated as word variables by the addition code Dim MyWord As Word MyWord word ByteVar AnotherByteVar Why do this If there are no casts then GCBASIC will add the two values using the byte addition code
105. rogram memory on the PIC which is given on the datasheet value is 14 bits wide and thus can store values up to 16383 This is an advanced command which should only be used by advanced developers ProgramErase must be used to clear a block of memory BEFORE ProgramWrite is called PS2ReadByite Syntax output PS2ReadByte Explanation 150 PS2ReadByte will read a byte from the PS 2 bus It will return the byte or 0 if no data was returned by the PS 2 device The PS 2 bus will normally be held in the inhibit state PS2ReadByte will uninhibit the bus for 25 ms If a response is received it will be read Then the bus will be placed back in the inhibit state Example For an example please refer to the INKEY function in the ps2 h file PS2SetKBLeds Syntax PS2SetKBLeds LedStatus Explanation This routine will turn the status LEDs on a keyboard on or off LedStatus is a variable of which the lower 3 bits correspond to the 3 LEDs Bit 0 is for Scroll Lock bit 1 controls Num Lock and bit 2 controls Caps Lock Note that this routine does not alter the status variables within the INKEY routine so even if the Caps Lock LED is turned on Caps Lock will stay off Example A spinning LED program for a keyboard Will flash Num Lock then Caps Lock then Scroll Lock Hardware settings chip 16F88 8 151 define PS2Clock PORTB 2 define PS2Data PORTB 3 define PS2_DELAY 10 ms Main Loop gt o
106. rol the port modes If ANSEL is defined then the chip is newer and its ports can be set to digital by clearing ANSEL Enabling code if a system bit is defined Similar to above except with Bit and NoBit in the place of Var and NoVar respectively 44 3 6 ifndef Syntax ifndef Constant Constant Value Var VariableName endif Explanation The ifndef directive is used to selectively enable sections of code It is the opposite of the ifdef directive it will delete code in cases where ifdef would leave it and will leave code where ifdef would delete it 3 7 include Syntax include filename Explanation include tells GCBASIC to open up another file read all of the subroutines and constants from it and then copy them into the current program There are two forms of include absolute and relative Absolute is used to refer to files in the C Program Files GCBASIC include directory The name of the file is specified in between lt and gt symbols For instance to include the file srf04 h the directive is include lt srf04 h gt Relative is used to read files in the same folder as the currently selected program Filenames are given enclosed in quotation marks such as include mycode h where mycode h is the name of the file that is to be read It is not essential that the include file name ends in h the important thing is that the name given to GCBASIC is the exact name of the file to be included
107. roller Potential uses include e Displaying debug text output from the microcontroller e Logging microcontroller data to a text file e Developing and debugging a microcontroller UART interface e Interfacing with and sending commands to the microcontroller during development The tool supports full duplex asynchronous serial communications from 150 to 38400 baud including custom non standard baud rates The PICkit 2 connects via the CHIPINO ICSP connector directly to microcontroller pin RB7 PICkit 2 RX and pin RB6 PICkit 2 TX at logic levels No transceiver is needed 204 _ Pin 1 Indicator N Pin Description 1 No Connect 2 VoD Target 3 Vss ground 4 RX PICkit 2 In 5 TX PICkit 2 Out J 6 No Connect OomhWh The 6 pin header 0 100 spacing accepts 0 025 square pins L Connecting the UART Tool The CHIPINO pins B6 and B7 are not connected to the headers These pins have holes located near the programming connection You can solder a three pin header there to make connecting easier Any pin you want to send data through can be connected to the B7 pin to send data to the PICkit 2 Terminal Software Any pin you want to receive data from the PICkit 2 terminal can be connected to the B6 pin An easier way though is to just route those signals through software to the B7 and B6 pins This way you have full access to the CHIPINO header pins for signals and use B7 and B6 for
108. s And Or Xor Ouron gt There are several modes in which variables can be set GCBASIC will automatically use a different mode for each calculation depending on the type of variable being set If a byte variable is being set byte mode will be used if a word variable is being set word mode will be used 36 If a byte is being set but the calculation involves numbers larger than 255 word mode can be used by adding WORD to the start of one of the values in the calculation This is known as casting section 2 4 If you prefer you can add LET to the start of the line It will not alter the execution of the program but is included for those who are used to including it in other BASIC dialects Example This program is to illustrate the setting of variables Chipmunk 46 Sets the variable Chipmunk to 46 Animal Chipmunk Sets the variable Animal to the value of Chipmunk Bear 2 3 5 Sets the variable Bear to the result of 2 3 5 17 Sheep 2 3 5 Sets the variable Sheep to the result of 2 3 5 25 Animal 2 Bear Sets the variable Animal to twice the value of Bear LargeVar 321 LargeVar must be set as a word see DIM Temp LargeVar WORD 5 LargeVar is a word size variable Note the use of WORD to ensure that the calculation is performed correctly 2 10 Conditions In GCBASIC and most other programming languages a condition is a statement that can be either true or false Conditions are
109. s connected to ground if not used 4 17 Tone Overview Introduction These routines generate tones of a given frequency and duration Note lf an exact frequency is required or a smaller program is needed these routines should not be used Instead you should use code like this Repeat count PulseOut SoundOut period us Wait period us End Repeat Set count and period to the appropriate values eperiod to 1000000 desired frequency 2 ecount to desired duration period Relevant Constants These constants are used to control settings for the tone generation routines To set them place a line in the main program file that uses define to assign a value to the particular constant 70 Constant Name Controls Default Value SoundOut 4 18 SPI Overview Command Availability The output pin to produce N A Must be set sound on Available on PIC microcontrollers with Synchronous Serial Port SSP module These commands control the SPI communication Syntax SPIMode Mode SPIMode sets the mode of the SPI module within the PIC chip These are the possible SPI Modes Mode Name Description MasterSlow Master mode SPI clock is 1 64 of the frequency of the PIC Master Master mode SPI clock is 1 16 of the frequency of the PIC MasterFast Master mode SPI clock is 1 4 of the frequency of the PIC Slave Slave mode SlaveSS Slave mode with the Slave Select pin enabled
110. s a comment line since it starts with an apostrophe light gcb This program monitors a photoresistor connected to the AN1 pin If it s in the dark it will light the LED on D13 If it s in the light then LED is shutoff Written for the CHIPINO Demo Shield The PIC16F886 in the CHIPINO is selected and then a header file with all the nicknames DO D13 and A0 A5 chip 16F 886 4 include lt chipino h gt 201 The A1 analog pin is set to an input to read the light sensor voltage The port direction for the D13 pin is also defined as an output The Digital pins don t need this since the GCB compiler automatically sets pins to outputs but added it here to show how to setup the output pin if you wanted to define it Dir A1 In Make Analog 1 pin input Dir D13 out Make D15 pin output Now we enter the main loop In this case it s an actual Do Loop command instead of the Lable Goto Lable I ve used previously The Do Loop will run whatever is between Do and Loop continuously added a Start label just to indicate where the main loop starts but it really serves no purpose to the program The ReadAD command is used to read the voltage on the A1 pin of the CHIPINO It will use the internal Analog to Digital Converter ADC built into the analog pins of the CHIPINO to convert the voltage at A1 to a value of 0 to 255 We can then compare that to a value in this case 150 to determine if the LED should ligh
111. s a matter of using the define directive Here are some examples of defines define Line 34 Line is a simple constant GCBASIC will find Line in the program and replace it with the number 34 This could be used in a line following program to make it easier to calibrate the program for different lighting conditions define Light PORTB O Light is a port it represents a particular pin on the PIC chip This would be of use if the program had many lines of code that controlled the light and there was a possibility that the port the light was attached to would need to change in the future define LightOn Set PORTB O on 29 LightOn is a define used to make the program more readable Rather than typing Set PORTB O on over and over it would then be made possible to type LightOn and have the compiler do the hard work 2 6 Numeric Constants GCB allows numeric constants to be defined in three bases decimal binary and hexadecimal Decimal are the default and require no prefix Binary and Hex numbers can be written in a couple formats but each requires a prefix Decimal 170 Binary 0610100101 Binary equivalent to 170 or b 10100101 Hex H AS Hex equivalent to 170 or OxA5 2 6 1 BCD to Decimal Sometimes you need to format numbers in Binary Coded Decimal format GCB doesn t have the function built in but you can easily add it with this function below Just add this to your GCB program and then cal
112. s is a purely arbitrary value here Loop Random Syntax var Random Explanation The Random function will generate a pseudo random number between 0 and 255 inclusive The numbers generated by Random will follow the same sequence every time until Randomize is used Example Set chip model chip tiny2313 1 Use randomize with the value on PORTD as the seed 159 Randomize PORTD Generate random numbers and output on PORTB Do PORTB Random Wait 1s Loop Randomize Syntax Randomize Randomize seed Explanation Randomize is used to seed the pseudo random number generator so that it will produce a different sequence of numbers each time it is used If no seed is specified then the RANDOMIZE_SEED constant will be used as the seed If seed is specified then it will be used to seed the generator It is important that the seed is different every time that Randomize is used If the seed is always the same then the sequence of numbers will always be the same It is best to use a running timer an input port or the analog to digital converter as the source of the seed since these will normally provide a different value each time the program runs Example Set chip model 160 chip tiny2313 1 Use randomize with the value on PORTD as the seed Randomize PORTD Generate random numbers and output on PORTB Do PORTB Random Wait 1 s Loop ReadAD Syntax var Read
113. s it appears on the display Click Log to File to bring up a Save File dialog Specify the file location and name and click Save While the terminal display is being saved to the log file the Log to File button will turn green and display the text Logging Data 208 Send Hex Sequences Wrap Text Gear Screen wn w w 4 Eat UART Tool To stop logging data from the display and close the log file click Logging Data Clear Screen Click the Clear Screen button to clear all text or data from the terminal display window If data is being logged to a file clearing the screen will not affect the log file Exit UART Tool Click Exit UART Tool to close the UART Tool window and return to the PICkit 2 Programmer application main window The UART Tool terminal display data and settings will be preserved during any programming operations until the UART Tool is re entered If the PICkit 2 application is closed the UART Tool settings including String Macros and Hex Sequences will be saved and restored for the next time the UART Tool is used The terminal display buffer text and data is not saved when the application is closed Logic Tool The PICkit 2 Logic Tool allows the PICkit 2 ICSP connector pins to be used for stimulating and probing digital signals in the CHIPINO and as a simple 3 channel logic analyzer The Logic Tool is opened by selecting Tools gt Logic Tool in the main PICkit 2 application window 209 The
114. s message Wait 10 ms Loop 106 I2CReceive Syntax I2CReceive data I2CReceive data ack Command Availability Available on all microcontrollers except 12 bit instruction PICs 10F 12F5xx 16F5xx chips Explanation The l2CReceive command will send data through the 12C connection If ack is TRUE or no value is given for ack then I2CReceive will send an ack If in master mode I2CReceive will read the data immediately If in slave mode I2CReceive will wait for the master to send the data before reading Example This program reads an I2C register and sets an LED if it is over 100 It_ will read from address 83 register 1 Chip settings chip 18F2620 8 I2C settings 107 define I2C_MODE Master define I2C_DATA PORTC 0 define I2C_CLOCK PORTC 1 Misc settings define LED PORTB 0 Main loop Do Send start I2CStart Request value I2CSend 83 I2CSend 1 Read value I2CReceive ValuelIn Send stop I2CStop Turn on LED if received value gt 100 Set LED Off If ValueIn gt 100 Then Set LED On 108 Delay Wait 20 ms Loop 12CSend Syntax l2CSend data l2CSend data ack Command Availability Available on all microcontrollers except 12 bit instruction PICs 10F 12F5xx 16F5xx chips Explanation The l2CSend command will send data through the 12C connection If ack is TRUE or no value is given for ack then 2CSend will wait for an Acknoledge bit fr
115. s of code if you want just by placing an apostrophe at the beginning of each line The SynGCB IDE has a feature to do this automatically It will coment out or comment in blocks of code that you highlight There is a comment out and comment in icon in the center toolbar jij me i Comment and Uncomment Icons 39 In some GCB sample programs you may also see comment lines starting with a semi colon or the term REM chip settings Rem This is a comment line Neither of these are automatically recognized by the IDE auto formatting so they will look like command lines but the Great Cow Basic compiler will recognize them as commented lines and not include them in the final compile It s best to just use the apostrophe for all commented lines so the IDE will show them as non highlighted comment lines This will make your code easier to read The comment uncomment toolbar icons will add apostrophes or remove them Example The number of pins to flash define FlashPins 2 You can create a header using an apostrophe before each line This is a great way to describe your program You can also use it to describe the hardware connections You can place comments above the command or on the same line Dir PORTB Out Initialise PORTB to all Outputs Main loop do PORTB 0 All Pins off Wait 1 S Delay 1 second PORTB OxFF All pins on Wait 1 s Delay 1 second Loop 40 3 0 Directives 3 1 chip Syntax chip mode
116. s of sensor readings ranging from 0 to 255 String A series of letters numbers Messages that are to be shown and symbols on a screen Using Variables Byte variables are automatically created in Great Cow Basic Just put the name of the variable in to the command where the variable is needed and the compiler will create the variable automatically Other types of variable must be dimensioned first This involves using the DIM commana to tell Great Cow BASIC that it is dealing with something other than a byte variable 24 Dim Var as Word Variable VAR can now hold 0 to 65 535 Dim Flag as Bit Flag variable will hold a 0 or 1 A key feature of variables is that it is possible the have the microcontroller check a variable and only run a section of code if it is a given value This can be done with the IF command Variable Aliases Some variables are aliases which are used to refer to memory locations used by other variables These are useful for joining predefined byte variable together to form word variables Alias are not like pointers in many languages they must always refer to the same variable or variables and cannot be changed One useful Alias is the the HighByte Low Byte for word variables Example Dim BigVar As Word Alias HighByte LowByte HighByte 2 LowByte 100 You can also access bits of a variable like this Remember though that the first bit is bit O not bit 1 So all eight bits of a byte variabl
117. s to connect the display s in whatever way is easiest and then set the DISP_SEG_x and DISP_SEL_x constants The first option setting DisplayPortx and DispSelectn will generate slightly more efficient code Configuration using DISP_SEG_x and DISP_SEL_x When setting up the 7 segment code with DISP_SEG_x constants these must be set Constant Name Controls Default Value DISP_SEG_x Controls the output ping used to control segment x of the displays There are 7 of these constants named DISP_SEG_A through DISP_SEG_G One must be set for each segment N A DISP_SEG_DOT Specifies the output pin used to control the decimal point on the displays N A DISP_SEL_x The command used to select display n Used to control addressing pins when several displays are multiplexed N A Note Instead of setting DISP_SEL_x it is possible to set DispSelectn and use these in conjunction with DISP_SEG_x 59 Configuration using DisplayPortn and DispSelectn To set the 7 Segment display routines supplied with GCBASIC using DisplayPortn it is necessary to set these constants Constant Name Controls Default Value DisplayPortn Controls the output port N A used to control display n nis A B C or D corresponding to displays 1 2 3 and 4 respectively DispSelectn The command used to nop select display n Used to control addressing pins wh
118. sc Settings define SCROLL_DELAY 250 ms General hardware configuration chip 16F877A 20 LCD connection settings define LCD_IO 8 define LCD_DATA_PORT PORTC define LCD_RS PORTD 0 define LCD_RW PORTD 1 define LCD_Enable PORTD 2 Main routine For StarPos UIO 16 If StarPos 0b Then Put 04 6 32 Put 0 0 42 Else Put 0 StarPos 1 32 Put 0 StarPos 42 End If 155 Wait SCROLL_DELAY Next PWMOff Syntax PWMOff Command Availability Only available on PIC microcontrollers with Capture Compare PWM CCP module Explanation This command will disable the output of the PWM module on the PIC chip Example This program will enable a 76 Khz PWM signal with a duty cycle of 80 It will emit the signal for 10 seconds then stop define PWM_Freq 76 Set frequency in KHz define PWM_ Duty 80 Set duty cycle to 80 PWMOn Turn on the PWM WAIT 10 s Wait 10 seconds PWMOff Turn off the PWM 156 PWMOn Syntax PWMOn Command Availability Only available on PIC microcontrollers with Capture Compare PWM CCP module Explanation This command will enable the output of the PWM module on the PIC chip Example This program will enable a 76 Khz PWM signal with a duty cycle of 80 It will emit the signal for 10 seconds then stop define PWM_Freq 76 Set frequency in KHz define PWM_Duty 80 Set duty cycle to 80 PWMOn Turn on the PWM WAI
119. sh button switch is a very common way to do that It can start and stop the operation or it could speed up or slow down what the microcontroller is controlling In order to do that though the software needs to recognize that a switch was pressed This project shows a simple method of sensing a momentary push button switch The software will have to monitor the switch continuously as part of the main loop of code and then respond In this project the software will light one LED until the switch is pressed at which point the LED will shut off and a second LED with light As long as the switch is pressed the first LED will stay off and the second LED will stay on As soon as the switch is released the first LED will once again light up and the second LED will shut off The completed project is shown in Figure 6 2 Jj a EL Ad Drawn with Fritzing org Figure 6 2 Switch Control 194 Hardware The hardware uses the same two Red LED connections as the train crossing project in Chapter 3 The addition of the switch is shown in Figure 6 2 The switch is wired as a low side switch meaning the circuit has a pull up resistor to 5 volts so the input the micro is high when the switch is not pressed and low when the switch is pressed This is known as a low side switch If the parts were reversed and the switch was connected to 5 volts and the resistor to ground then it would be a high side switch The software will change pin 8 to an input
120. sible to specify how many times the trigger condition must occur before waveform capture is initiated up to 256 times maximum For example suppose we wanted to capture the 16th byte of a long SPI transmission sequence If we triggered on the first clock edge of the first byte we probably wouldn t be able to see the 16th byte as the analyzer would stop 217 sampling before it occurred However we can set the analyzer to pass up the first 15 bytes by setting the trigger count to 15 bytes 8 clocks 1 121 times This way it will start counting clock edges on the first byte but it won t trigger the data capture until the 16th byte is transmitted Analyzer Acquisition The Acquisition section of the analyzer window is used to set the waveform sample rate the position of the trigger relative to the captured waveform and to start or run the analyzer Aquisition Sample Rate 1 MHz 1 ms Window v NOTE Signals greater than 500 kHz will alias RUN Trigger Position Start of Data Delay 1 Window D Center of Data Delay 2 Windows End of Data Delay 3 Windows 7 Window 7000 samples Sample Rate The sample rate is how often the analyzer channels are looked at Each waveform capture is only 1024 samples long so if we want to look at a longer period of time in the waveform display we have to sample less often The trade off is that at higher sample rates we can see more detail and faster sign
121. sorReading ExecCommand True End If End Function 174 SerReceive Syntax SerReceive channel output Explanation This command will read a byte from the RS232 channel given by channel according to the rules set using InitSer and store the received byte in the variable output Example This program will read a byte from PORTB 2 and set the LED on if the byte is more than 50 This can be used with the SerSend example program chip 16F88 8 config Osc Int define RecAHigh PORTB 2 ON define RecALow PORTB 2 OFF define LED PORTB 0 Dir PORTB 0O Out Dir PORTB 2 In 175 InitSer 1 r9600 1 WaitForStart 8 Do SerReceive 1 Temp If Temp lt 50 Then Set LED Off If Temp gt 50 Then Set LED On Loop SerSend Syntax SerSend channel data Explanation 1 none normal This command will send a byte given by data using the RS232 channel referred to as channel according to the rules set using InitSer Example This program will send a byte using PORTB 2 depends on whether a button is pressed example for SerReceive chip 16F819 8 config Osc Int 176 the value of which This can be used with the define SendAHigh Set PORTB 2 ON define SendALow Set PORTB 2 OFF define Button PORTA 0 Dir Button In Dir PORTB 2 Out InitSer 1 r9600 1 WaitForStart 8 1 none normal Do If Button On Then Temp 100 If Button Off Then Temp 0 S
122. splay a new line the CHIPINO must transmit the character values 0x0D carriage return and OxOA line feed in sequence If one of these values is sent or they are sent in reverse order the character s will appear as an unprintable character box in the display Bytes may be transmitted in three ways 1 Click on the terminal display to select it Any characters typed on the PC keyboard will be immediately transmitted out of PICkit 2 2 Right click on the terminal display and select Paste from the pop up menu to paste any previous copied or cut text lt Ctrl gt lt v gt may also be used Any pasted data will immediately be transmitted out of PICkit 2 3 Use the String Macros at the bottom of the window The String Macros allow up to four strings of characters to be entered Each string can be up to 60 characters long When Send is clicked the entire string will be transmitted in sequence out of the PICkit 2 The String Macros strings are saved even when the UART Tool is not in use When checked the Append CR LF checkbox above the string macro boxes will automatically transmit the carriage return OxOD and line feed Ox0A characters at the end of a string When unchecked nothing is transmitted after the string characters No transmitted characters will be displayed if the Echo On checkbox is unchecked Check this box to display transmitted characters along with received characters in the terminal display Text in the termin
123. steps it takes 114 Set pin directions Dir GLCD_RS Out Dir GLCD_RW Out Dir GLCD_ENABLE Out Dir GLCD_CS1 Out Dir GLCD_CS2 Out Dir GLCD_RESET Out Reset Set GLCD_RESET Off Wait ms Set GLCD_RESET On Wait ms Select both chips Set GLCD_CS1 On Set GLCD_CS2 On Set on Set GLCD_RS Off GLCDWriteByte 63 Set Z to 0 GLCDWriteByte 192 Deselect chips Set GLCD_CS1 Off Set GLCD_CS2 Off Clear screen GLCDCLS 115 InitSer Syntax InitSer channel rate start data stop parity invert Explanation This command will set up the serial communications The parameters are as follows channel is 1 2 or 3 and refers to the I O ports that are used for communication rate is the bit rate which is given by the letter r and then the desired rate in bps Acceptable units are r300 r600 r1200 r2400 r4800 r9600 and r19200 start gives the number of start bits which is usually 1 To make the PIC wait for the start bit before proceeding with the receive add 128 to start Note it may be desirable to use the WaitForStart constant here data tells the program how many data bits are to be sent or received In most situations this is 8 but it can range between 1 and 8 inclusive stop is the number of stop bits If start bit 7 is on then this number will be ignored parity refers to a system of error checking used by many devices It can be odd in which there must always be an odd number of h
124. t gt 0 Condition is true if Sensor is not 0 Reading1 gt Reading2 True if Reading1 is more than Reading2 Mode 1 AND Time gt 10 True if Mode is 1 and Time is more than 10 Heat gt 5 OR Smoke gt 2 True if Heat is more than 5 or Smoke is more than 2 Light gt 10 AND NOT True if Light is 10 or more and Time is 7 or less Time gt 7 Temp 0 ON True if Temp bit 0 is on 2 11 Combining Multiple Instructions It is possible to combine multiple instructions on a single line by separating them with a colon For example this code 38 Set PORTB O On Set PORTB 1 On Wait 1 sec Set PORTB O Off Set PORTB O Off Could also be written as Set PORTB O On Set PORTB 1 On Wait 1 sec Set PORTB O Off Set PORTB 0O Off In most cases it will make no difference if commands share a line or not However special care should be taken with IF commands as this code Set PORTB O Off Set PORTB 1 Off If Temp gt 10 Then Set PORTB O On Set PORTB 1 On Wait 1s Will be equivalent to this Set PORTB O Off Set PORTB 1 Off If Temp gt 10 Then Set PORTB O On Set PORTB 1 On End If Wait 1s Also the commands used to start and end subroutines data tables and functions must be alone on a line For example this is WRONG Sub Something Set PORTB 0 Off End Sub 2 12 Comments Adding comments to your GCB program is done with an apostrophe before the comment line You can also comment out section
125. t or not If the value converted by the ReadAD command is less than 150 dark then the D13 LED is turned on If the value is greater than 150 light then the D13 LED is turned off Start Do Light LED if in the dark If ReadAD A1 lt 150 Then set D13 on Sensor is Dark else set D13 off Bright light on sensor end if Loop 202 Appendix A PICkit 2 GUI Features The PICkit 2 Programmer from Microchip is an open source hardware programmer The Great Cow Basic CHIPINO USB Programming cable is actually a PICkit 2 Programmer shrunk down to a cable The PICkit 2 USB Programming Cable can do more than program the CHIPINO module It can also receive signals for a terminal program called the UART Tool and display signals in digital mode or in a logic analyzer graphic mode with the Logic Tool This appendix will cover those features You can launch the PICkit 2 GUI from the GCB IDE toolbar by clicking on the PICkit2 Icon ti i oe ih Note When using the PICkit 2 GUI features you can t program the CHIPINO using the built in PICkit 2 programmer application associated with the Blue Arrow compile and program icon You ll need to shut down the PICkit 2 GUI then reprogram the CHIPINO then relaunch the PICkit 2 GUI UART Tool The PICkit 2 Programmer GUl includes the UART Tool feature This feature allows the CHIPINO USB Progarmmer cable to be used as a serial UART terminal interface for communicating with a PIC microcont
126. the direction which is either In or Out The entire port form is similiar to the TRIS instruction offered by some PIC chips To use it give the name of the port ie PORTA and then a byte is to be written into the TRIS variable This form of the command is for those who are familiar with the PIC chip s internal architecture WARNING PICs use 0 for out and 1 for in When IN and OUT are used there are no compatibility issues 79 Example This program sets PORTA bits 0 and 1 to in and the rest to out It also sets all of PORTB to output except for B1 Individual form is used for PORTA DIR PORTA O IN DIR PORTA 1 IN DIR PORTA 2 OUT DIR PORTA 3 OUT DIR PORTA 4 OUT DIR PORTA 5 OUT DIR PORTA 6 OUT DIR PORTA 7 OUT Entire port form used for B DIR PORTB b 00000010 Entire port form used for C DIR PORTC IN DisplayChar Syntax DisplayChar display character Explanation 80 This command will display the given ASCII character on a seven segment LED display display is the number of the display to use and character is the ASCII character to show Example This program will show Hello on a LED display The display should be connected to PORTB chip 16F877A 20 define DisplayPortA PORTB Dim Message As String Message Hello For Counter 1 to 6 DisplayChar 1 Message Counter Wait 250 ms Next DisplayValue Syntax DisplayValue display data Explanatio
127. the variable a byte Alias creates a variable using the same memory location as one or more other variables It is mainly used internally in GCBASIC to treat system variables as a word For example this command is used to create a word variable made up from the two memory locations used to store the result of an A D conversion A variable can be placed at a specific location in the data memory of the chip using the At option location will be used whether it is a valid location or not but a warning will be generated if GCBASIC has already allocated the memory or if the memory does not appear to be valid This can be used for peripherals that have multi byte buffers in RAM Dim ADResult As Word Alias ADRESH ADRESL Example This program will set up an array and a word variable dim DataList 10 dim Reading as word Reading 21978 DataList 1 15 78 Dir Syntax Dir port bit In Out Individual Form Dir port In Out DirectionByte Entire Port Form Command Availability Available on all microcontrollers However some low end PIC microcontrollers 10F 12F5x and 16F5x chips will only accept the entire port form Explanation The Dir command is used to set the direction of the ports of the microcontroller chip The individual form sets the direction of one pin at a time whereas the entire port form will set all bits in a port In the individual form specify the port and bit ie PORTB 4 then
128. this setup all you need is a PC running Windows XP Vista or Win7 or a Mac running Parallels or VMWare and Windows The CHIPINO makes it easy for a beginner to use Great Cow Basic because of all the pre built plug in shields thatstack on top There are numerous code examples for this starter kit at www greatcowbasic com LCD Shield and Demo Shield You can also use it with a CHIPINO Breadboard Module You can also use Great Cow Basic with the CHIPAXE modules from Howtronics com These modules make it easy to use GCB with 8 pin 14 pin 18 pin 20 pin and 28 pin Microchip PICs You can also use Great Cow Basic to program an 8 pin PIC Microcontroller and use it with Snap Circuits There are also adapters to plug a CHIPAXE module into a Snap Circuits module 10 Minimum Required All you really need to use Great Cow Basic is a Microchip PIC Microcontroller and a programmer It works great with a Microchip PICkit2 or one of the many PICkit 2 clones since the PICKit 2 design is also open source ow MICROCHIP PICkit Original PICkit 2 PK2 Clone PICkit 2 Clone 11 The Great Cow Basic Compiler supports all the 8 bit Microchip PICs including all the parts that start with PIC18F PIC16F PIC12F and PIC10F A very common part to start with is the PIC16F886 It s a 28 pin part that has most of the features all the other PICs have including Internal Oscillator Internal MCLR resistor option 10 bit Analog to Di
129. tines A subroutine is a small program inside of the main program Subroutines are typically used when a task needs to be repeated several times in different parts of the main program There are two main uses for subroutines Keeping programs neat and easy to read Reducing the size of programs by allowing common sections of code to be reused When the PIC comes to a subroutine it saves its location in the current program before jumping to the start of or calling the subroutine Once it reaches the end of the subroutine it returns to the main program and continues to run the code where it left off previously 51 Normally it is possible for subroutines to call other subroutines There are limits to the number of times that a subroutine can call another sub which vary from chip to chip PIC Family Instruction Width Number of subs called 10F 12C5 12F5 12 1 16C5 16F5 12C 12F 16C 16F except those above 18F 18C These limits are due to the amount of memory on the PIC which saves its location before it jumps to a new subroutine Some GCBASIC commands are subroutines so you should always allow for 2 or 3 subroutine calls more than your program has Another feature of subroutines is that they are able to accept parameters These are values that are passed from the main program to the subroutine when it is called and then passed back when the subroutine ends Using Subroutines To call a subroutine
130. trols Default Value I2C_MODE Mode of 12C routines Master Master or Slave I2C_DATA Pin on microcontroller N A connected to 12C data l2C_CLOCK Pin on microcontroller N A connected to 12C clock I2C_BIT_DELAY Time for a bit used for 2 us acknowledge detection I2C_CLOCK_DELAY Time for clock pulse to 1 us 57 remain high I2C_END_DELAY Time between clock 1 us pulses I2C_USE_TIMEOUT Set to true if slave mode Not Set I2C routines should stop waiting for the master and exit after a timeout occurs 4 10 Timer Overview Several functions are provided to read the current timer value They are eTimerO eTimer1 eTimer2 eTimer3 eTimer4 eTimer5 Not all of these functions are available on all chips For example if a chip only has 3 timers then only TimerO Timer1 and Timer2 will be available TimerO and Timer2 return byte values while Timer1 Timer3 Timer4 and Timer5 will return words Please refer to the datasheet for your microcontroller to determine the number and size of the timers available 4 11 Seven Segment Overview Introduction The 7 segment display routines make it easier for GCBASIC programs to display numbers and letters on 7 segment LED displays 58 There are two ways that the 7 segment display routines can be set up One option is to connect the wires from the display s in a particular order and then to set the DisplayPortn and DispSelectn constants The other option i
131. ue in brackets immediately after the name of the array Examples of array names are Array Index Meaning Fish 10 Element 10 of an array called Fish DataLog 2 The second number in an array named DataLog ButtonList Temp An element in the array ButtonList that is selected according to the value in the variable Temp Using Arrays To use an array its name is specified then the index Arrays can be used everywhere that a normal variable can be used Setting an entire array at once It is possible to set several elements of an array with a single line of code This short example shows how Dim TestVar 10 TestVer 1 2 3 4 5y 6 7 S39 Element 0 of TestVar will be set to the number of items in the list which in this case is 9 Each element of the array will then be loaded with the corresponding value in the list so in the example TestVar 1 will be set to 1 TestVar 2 to 2 and soon If there are many items in the array it may be better to use a Lookup Table to store the items and then copy some of the data items into a smaller array as needed 47 4 2 Functions Functions are a special type of subroutine that can return a value This means that when the name of the function is used in the place of a variable GCBASIC will call the function get a value from it and then put the value into the line of code in the place of the variable Functions may also have parameters these are treated
132. ule If the RS232 lines are connected elsewhere or the microcontroller has no RS232 module then the software based routines must be used 63 Relevant Constants These constants affect the operation of the hardware RS232 routines Constant Name Controls Default Value USART_BAUD_RATE Baud rate in bps for the N A routines to operate at USART_BLOCKING If set this constant will Not set cause the USART routines to delay until data can be sent or received If not set then the data will be buffered and send by the hardware when possible 4 15 Keypad Overview Introduction The keypad routines allow for a program to read from a 4 x 4 matrix keypad There are two ways that the keypad routines can be set up One option is to connect the wires from the keypad in a particular order and then to set the KeypadPort constant The other option is to connect the keypad in whatever way is easiest and then set the KEYPAD_ROW_x and KEYPAD_COL_x constants The first option setting KeypadPort will generate slightly more efficient code Configuration using KEYPAD_ROW_x and KEYPAD_COL_x These constants must be set Constant Name Controls Default Value KEYPAD_ROW_1 The pin on the N A microcontroller that connects to the Row 1 pin on the keypad KEYPAD_ROW_2 The pin on the N A microcontroller that connects to the Row 2 64 pin on the keypad
133. used when the program must make a decision A condition is generally given as a value or variable a relative operator such as or gt or another value or variable Several conditions can be combined to form one condition through the use of logical operators such as AND and OR GCBASIC supports these relative operators Symbol Meaning Equal lt gt Not Equal lt Less Than 37 gt Greater Than Less than or equal to Equal to or greater than In addition these logical operators can be used to combine several conditions into one Name Abbreviation Condition true if AND amp both conditions are true OR at least one condition is true XOR one conditionis true NOT the condition is not true NOT is slightly different than the other logical operators in that it only needs one other condition Other arithmetic operators may be combined in conditions to change values before they are compared GCBASIC has two built in conditions TRUE whichis always true and FALSE which is always false These can be used to create infinite loops It is also possible to test individual bits in conditions To do this specify the bit to test then 1 or 0 or ON and OFF respectively Presently there is no way to combine bit tests with other conditions NOT AND OR and XOR will not work Example conditions Condition Comments Temp 0 Condition is true if Temp 0 Sensor l
134. ve output Used as function output HSerReceive Command Availability Available on all microcontrollers with a USART or UART module Explanation This command will reada byte from the hardware RS232 module It can be used either as a subroutine or as a function If used as a subroutine a variable must be supplied to store the received value in If used as a function it will return the received value Example This program will read a value from the USART and display it on PORTB chip 16F877A 20 USART settings 104 define USART_BAUD_RATE 9600 Set PORTB to input Dir PORTB Out Set USART receive pin to input Dir PORTC 7 In 4 Main loop Do oO Get and display value If there is no new data HSerReceive will etuEn old value HSerReceive PORTB Could also write Ld Loop P a PORTB HSerReceive ao Syma HSerSend data Command Availability Available on all microcontrollers with a USART or UART module 105 Explanation This command will send a byte given by data using the hardware RS232 module Example This program will send the status of PORTB through the hardware serial module chip 16F877A 20 USART settings define USART_BAUD_RATE 9600 Set PORTB to input Dir PORTB In Set USART transmit pin to output Dir PORTC 6 Out Main loop Do Send PORTB value through USART HSerSend PORTB Short delay for receiver to proces
135. y byte or word variable or a fixed number between 0 and 65535 inclusive The string variable stringvar will contain the same number represented as a string This function is especially useful if a number needs to added to the end of a string or if a custom data sending routine has been created but only supports the output of string variables Syntax stringvar Str number Example Take an A D reading SensorReading ReadAD AN0 Create a string variable Dim OutVar As String Fill string with sensor reading OutVar Str SensorReading Send HSerPrint OutVar HSerPrintCRbF 2 8 7 Retrieve String Characters Left The Left function will extract the leftmost count characters from the input string source and return them in a new string Syntax output Left source count Example Dim TestData As String TestData Hello world 34 Display the leftmost 5 characters Will display Hello HSerPrint Left TestData 5 2 8 8 Retrieve String Characters Middle The Mid function is used to extract characters from the middle of a string variable source is the variable to extract from start is the position of the first character to extract and count is the number of characters to extract If countis not specified all characters from start to the end of the source string will be returned Syntax output Mid source start count Example Extract cat The c is at position 5 and 3 letters are needed
136. y digital signal it is connected to Generally this is only an issue when using Pin 4 or Pin 5 as an input 211 When a pin is selected as an Output the pin will drive the logic level shown in the read Outputs box Toggle the output state by clicking on the Output state box Alternatively a keyboard shortcut key can used for each pin to toggle the output The shortcut keys are Pin Shortcut Key 1 lt A gt 4 lt S gt 5 lt D gt 6 lt F gt 212 Logic Analyzer Mode The Analyzer mode of the PICkit 2 Logic Tool enables using the PICkit 2 GUI as a simple three channel logic analyzer to capture view and measure the digital waveforms of up to three signals EE PICKit 2 Logic Tool Ch1 amp Ch2 inputs have 4 7k Ohm pull down resistors PICkit 2YDD MUST connect t circuit VDD Set VDD Votage On O in main form Help Enable Disable N Cursors 50 us J Div X Cursor Left click mouse Trigger Trigger when w Don t Care Mode Logic 0 Analyzer Sample Rate 1 MHz 1 ms Window v RUN 1 Logic High NOTE Signals greater than 500 kHz will alias 0 Logic Low Tri Position Rising Edge SES are lt Start of Data Delay 1 Window Center of Data Delay 2 Windows End of Data D Delay 3 Windows 7 we Ti Exit Logic Tool Time difference from Time delta between cursors cursor to trigger period frequency J Y Cursor Right click mouse Connect

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GCBC Starter Kit User Manual