AVRSimon - Nuts & Volts Magazine
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1. Assembled avrsimon game with custom circuit board A PALAX amp information The Atmel ATtiny2313 microcontroller www atmel com dyn products product_card asp part_id 4660 is an eight bit microcontroller based on the AVR enhanced RISC Reduced Instruction Set Computer architecture It features 2 KB of Flash 128 bytes of in system programmable EEPROM 128 bytes of RAM up to 20 MHz clock speed 1 8V to 5 5V operation and up to 18 general purpose I O pins all in a 20 pin package Peripherals include two timers four PWM channels analog comparator and a Universal Serial Interface UART It is a nice low cost part around 2 in small quantities suitable for many embedded systems projects One side of each button SW1 SW2 SW3 SW4 is connected to Port B 1 4 0 and 3 respectively The other side of the buttons are connected to ground The internal pull up resistor with a value between 20K and 50K ohm according to the ATtiny2313 datasheet is enabled on each of the Port B pins removing the need for four external resistors The buttons are active low so the microprocessor normally sees a high signal 1 due to the pull up resistor when the button isn t being pressed When a button is pressed the microprocessor sees a low signal 0 The cathodes of the four LEDs matching the four colors of the original Simon game D1 red D2 blue D3 on e COON f 1 B Off On gt ad ww ia GT2. 18 OT 600Z v LOTS tASY woo xe Te eda zoddns xere seq hq paamcesnuey w03 oTpmiseap pue nnn otpis espr pueg hq paubtsag ug uang b wzunv uonngusng NS se BBF HEG gee oueg reld A E usang 1eaday pue eztoway TTT 0025 Tonnnsu Arqeossy sapien henveg ZEOZED 2 f 2 ceuondo sapeay Gurewe bo saps green D4 yellow are connected to Port D 0 3 1 and 2 respectively A current limiting resistor R1 R3 R4 R2 connected to VCC is used in series with each LED to limit the amount of current allowed to flow through it which sets the brightness and prevents excessive current from damaging the LED Like the buttons the LEDs are active low and set up in a current sink configuration meaning they will turn on when the output signal on one of the Port D pins is low 0 When we want to turn an LED off we simply set the corresponding pin s output value to high 1 Each port pin on the ATtiny2313 can safely sink 20 mA which is well above what the LEDs on avrsimon require When the red LED is on it requires 1 3 mA the green 3 0 mA blue 0 13 mA and yellow 3 2 mA One side of the piezo buzzer LS1 is connected to ground and the other side is connected to Port B 2 via R6 a current limiting resistor Instead of using the general purpose I O function as with the button inputs and LEDs Port B 2 is used as its special function Output Compare for Timer O which outputs waveforms that w
3. the player s input If the values do not match then the player must have pushed the wrong button and the game will end via the simon_failed_input function If the values do match then the player pushed the correct button and the game proceeds to the next move in the sequence If the player successfully repeats the entire sequence the game jumps back to simon_play_moves to add another move to the sequence and repeats the process until the game is over Sound Tone generation is based on the xyloduino project www rocketnumbernine com 2009 03 27 xyloduino simple arduinopiezo organ and modified to support arrays of octaves notes and durations in order to create melodies Timer 0 a hardware peripheral internal In order to play a melody a sequence of notes stored in an array must be played one after the next for i 4 i oll O i lt STARTGAME_SND_SIZE i 4 octave note length play_note pgm_read_byte startgame_ snd_p i pgm_read_byte startgame_snd_p i 1 pgm_read_word startgame_snd_p i 2 delay_ms 50 pause in between notes The four sounds generated on the original Simon were based on four primary notes of a bugle which sound in tune when played in any order avrsimon closely mimics those notes www waitingforfriday com index php Reverse_engineering_an_MB_Electronic _Simon_game Tone 1 Blue 392 Hz G note Tone 2 Yellow 330 Hz E note Tone 3 Red 2
4. 62 Hz C note Tone 4 Green 196 Hz G note Development Environment avrsimon was developed on OS X using CrossPack for AVR www obdev at products crosspack download de html Formerly known as AVR MacPack the package contains the core compiler debugger and AVR specific simon_game to U1 is used as an eight bit counter that will toggle the OCOA output pin Port B pin 2 from low to high or high to low when the counter value TCNTO matches the value programmed into the Output Compare Register OCROA The toggling of the output pin will generate a square wave at the desired frequency that is fed into the piezo buzzer LS1 The play_note routine is passed the octave note and length of the sound It configures the Timer Counter Control Register TCCROB and OCROA accordingly waits for the sound to be played and then disables the counter if note TCCROB pre int octave set the prescaler depending on what octave is selected OCROA note gt gt octave 2 there are two octaves for each prescale setting so adjust accordingly delay_ms length play sound for specified length TCCROB 0 turn off sound hardware_init simon_config simon_game FIGURE 3 High level program flow rag pressed Y prepare for gameplay FIGURE 4 Flowchart for the core ong Is move correct N simon_failed_ input Y create the next m
5. The Projects of dvrsimon A Do It Yourself Game Prototype This an engineering entertainment program on Discovery Channel offered a view into the real life process of designing and building unique prototypes In this 13 episode series which was filmed over the course of 18 months and aired starting in October 2008 we set out to tackle the problems of today by creating crazy one of a kind inventions of tomorrow was the team s electrical engineer and hardware hacker and shared the screen with Zoz Brooks a roboticist and software designer specializing in human machine interaction Mike North a material scientist and mechanical engineer and Terry Sandin a special effects veteran We were challenged to build things that had never been done before looked cool on TV and could be completed within the extremely tight financial and time constraints of television production It was a fantastic adventure and great experience to say the least This quarterly series of articles will cover the electronic aspects of some of my favorite projects from the show My hope is that you will be inspired learn something new or use my work as a building block for your own open source project Let s begin All photos and figures by Joe Grand 42 NUTS VOLTS March 2010 With Joe Grand l Launched in 1978 by Milton Bradley the addictive flying saucer shaped memory game of Simon remains an icon of early electronic games The
6. d reduces the length of time allowed for you to repeat the sequence Normally you have five seconds to make a decision for each move In fast mode you re only allowed two SW3 No LED Mode 46 NUTS VOLTS March 2010 No LEDs are illuminated while in this mode You ll have to repeat the pattern based on sound alone e SW4 Reverse Move This mode operates like a FIFO First In First Out stack in which you have to replay the sequence in reverse order instead of repeating the exact order that the game presents To revert back to game s normal mode of operation simply power cycle the unit Enjoy the game NV Joe Grand is an electrical engineer hardware hacker and president of Grand Idea Studio Inc www grand ideastudio com where he specializes in the invention design and licensing of consumer products and modules for electronics hobbyists He can be reached at joe grandideastudio com
7. ill drive the piezo buzzer Turning the game on and off is achieved with a simple slide switch used in an SPST configuration that connects and disconnects the battery supply from the VCC LSI PKMI17EPPH4001 BO R6 330 ohm PAO XTALI PAI XTAL2 e SW3 SKHHAJA010 PBO AINO PCINTO SW_GREEN o o SW1 PBI AINI PCINTI eRe 5 o PB2 OCOA PCINT2 TONE PIN SW_YELLOW SW4 m o o PB3 OC1A PCINT3 i 3 SW2 PB4 OC1B PCINT4 SW_BLUE oO C1 0 luF 4 2 R4 R3 RI 1 3 3k 330 ohm 330 ohm Ik CC D2 D4 D3 DI RS SSL LX5093USBD LTL 307Y LTL 307G LTL 307E 10k 20 vcc pao RESETaw LED_RED 2 PDO RXD LED_GREEN 3 PDI TXD LED_YELLOW 6 pp2 CKOUT XCK INTO LED_BLUE x PD3 INTI 8 Posto CR2032 3V 225mAh AA voc 2 PD5 OCOB T1 BT1 MPD BU2032SM HD G 1 eR PD6 ICP 10 ES SW5 EG1271 GND y Ul A z r ATTINY2313V 10PU FIGURE 2 avrsimon s schematic PBS MOSI DI SDA PCINTS VCC PB6 MISO DO PCINTS mso m T PB7 UCSK SCL PCINT7 SCK I MOSI RST 5 O PI Header 3X2 AVR ISP March 2010 NUTSVOLTS 43 VCC bus of the circuitry The system is powered with a single CR2032 3V lithium coin cell which is easy to obtain from any local drugstore convenience store or electronics outlet The CR2032 has a very nice current capacity for its size 20 mm in diameter of approxi
8. imeout counting used during gameplay and enables the Pin Change Interrupt Then simon_config is called which sets the gameplay mode based on the combination of pushbuttons SW1 SW4 held down during power up If no buttons are pressed during power up then the game will play in the normal mode Other modes include no sound mode fast mode no LED mode and reverse mode and serve as an additional challenge for advanced users Details of each special mode are discussed in the How to Play section of this article After all configurations are complete we move into the core simon_game routine Immediately after entering simon_game the system is configured to enter a low power sleep mode and to awake on a button press from any of the four buttons Sleep mode is attained by calling a specific sequence of functions macros which define the type of sleep mode we want to enter configure the interrupts and then go to sleep prepare to go to sleep idle mode set_sleep_mode SLEEP_MODE_PWR_DOWN Cla hy disable global interrupts sleep_enable sei enable global interrupts sleep_cpu now go to sleep to save power Sleep mode conserves a significant amount of power by shutting down all unused modules of the microcontroller and only keeping the absolute essential features awake In our selected Power Down Mode SLEEP_MODE_PWR_DOWN all clocks and oscillators are disabled all peripheral modules are tur
9. mately 225 mAh although the lithium battery chemistry works best for applications requiring very low current discharge tenths of mA over months or years of use Its maximum recommended continuous discharge is 3 mA which is what avrsimon draws during gameplay When the game is not being used and while the system is waiting for a button press to begin a new game U1 is placed into a sleep mode and current consumption is reduced to a scant 19 5 uA With typical gameplay of a few hours a day a single battery should last over a month There are a few other discrete components used in this design C1 is a standard bypass decoupling capacitor connected close to the VCC input of U1 R5 is a pull up resistor connected to the active low RESET line of U1 that keeps the microcontroller operating properly e g not resetting unless the pin is intentionally pulled low P1 is the standard six pin AVR In System Programming ISP header This is an optional part that is only required if you plan on making changes to the firmware and want to reprogram U1 while it is in circuit Firmware At the highest level the operation of avrsimon s firmware is straightforward Upon power up the hardware is initialized within the aptly named hardware_init function which brings the system into a known state The function configures the I O pins LED pins as outputs switch pins as inputs sets up the timers Timer O is used for tone generation and Timer 1 for t
10. ned off and the only ways to awaken the device are via specific resets external watchdog or brown out serial interface or INTO external interrupts or a Pin Change Interrupt generated on specific port pins For more details on sleep mode implementations see www nongnu org avr libc user manual group__avr__sleep html With avrsimon when a button press is detected via the Pin Change Interrupt on Port B O 1 3 or 4 corresponding to SW3 SW1 SW4 SW2 respectively the system springs to life and begins the game The game itself is comprised of two core functions simon_play_moves and simon_read_moves simon_play_moves first pulls a number from rand a linear feedback shift register used as a pseudo random number generator http en wikipedia org wiki PRNG which is seeded at the beginning of each game with the current value of U1 s Timer 1 counter and whatever Qty Reference Description Distributor Part BT1 Battery holder CR2032 Lithium coin cell SMT Digi Key BU2032SM HD GCT ND www digikey com C1 0 1 u 50V 10 bypass capacitor ceramic axial X7R Digi Key 1109PHCT ND D1 5 mm LED red high efficiency diffused 19 mcd 2 0V Digi Key 160 1705 ND D2 5 mm LED blue diffused 300 mcd 3 5V Digi Key 67 1751 ND 7 2 p D3 5 mm LED green diffused 19 mcd 2 1V Digi Key 160 1706 ND eee pee D4 5 mm LED yellow diffused 29 mcd 2 1V Digi Key 160 1703 ND Be eal eA a LS1 Piezoelectric buzzer 72 dB 25V pp 4 kHz PCB moun
11. ove and add to sequence March 2010 NUTSVOLTS 45 tools and integrates seamlessly with Apple s Xcode In circuit device programming was achieved using an adafruit industries USBtinylSP interface www adafruit com index php main_page product_info amp cPath 16 amp products_id 46 If you choose to modify avrsimon s firmware you ll need to recompile the code and reprogram it into the microcontroller To reprogram the microcontroller hook up the USBtinylSP to P1 insert and solder this optional six pin male header onto avrsimon if you haven t done so already locating pin 1 by its square pad on the backside of the circuit board Then open a Terminal window and go to your firmware directory Finally run the make install command which launches the avrdude application twice with different parameters once to load the compiled Hex file into Flash memory and once to set the device s configuration fuses defined in the Makefile 1 avrdude c usbtiny p attiny2313 U flash w main hex i 2 avrdude c usbtiny p attiny2313 U hfuse w 0xd1 m U Ifuse w 0xe4 m For more information on Atmel AVR development see AVR Freaks web page www avrfreaks net e adafruit industries AVR Tutorial web page www ladyada net learn avr How to Play In a nutshell avrsimon gameplay is as follows e Turn On Play Game e Memorize and Repeat Pattern e Score Given When Game Over When you first power up the game a start up
12. premise is simple Repeat the sequence of lights and tones This article presents my Simon clone running on an Atmel ATtiny2313 an eight bit AVR microcontroller Figure 1 My implementation of the game combines a number of basic microcontroller functions such as reading switch inputs and turning LEDs on and off with more complicated ones such as using sleep modes to extend battery life and playing sounds I ve also designed in a few gameplay enhancements such as no sound mode fast mode no LED mode and reverse mode Details of the original Simon design can be found in US Patent 4 207 087 entitled Microcomputer controlled game www google com patents about id MAlyAAAAEBAJ amp dq 4207087 Full engineering documentation including source code and PCB Gerber plots is available on my website www grandideastudio com portfolio avrsimon If you don t want to build the circuit from scratch a kit is available from Parallax www parallax com and includes all of the necessary components including a pre programmed microcontroller and custom circuit board The only additional items you ll need to build the kit are a soldering iron solder wire snips and a battery Hardware Like the original game avrsimon s user interface is simple comprising of four buttons four LEDs and a piezo buzzer for playing sounds Refer to the schematic Figure 2 and bill of materials Table 1 for specific component FIGURE 1
13. t Digi Key 490 4694 ND Header 3x2 vertical male PCB mount 1 0K ohm 5 1 4W R2 3 3K ohm 5 1 4W P1 optional R1 T G a aaa ae A a eS R3 R4 R6 330 ohm 5 1 4W R5 10K ohm 5 1 4W SW1 SW2 SW3 SW4 SPST momentary pushbutton switch 100 gf PCB mount SW5 SPDT slide switch 300 mA PCB mount L 2 mm U1 AVR microcontroller DIP20 Socket DIP20 Printed circuit board U1b optional PCB 44 NUTS VOLTS March 2010 Digi Key 3M9459 ND Digi Key 1 0KQBKND Digi Key 3 3KQBK ND Digi Key 3300BK ND Digi Key 1OKQBK ND Mouser 688 SKHHAJ www mouser com Digi Key EG1918 ND Mouser 556 ATTINY2313V10PU Digi Key 3M5465 ND Parallax pushbutton was pushed to start the game The number from rand is limited from O to 3 corresponding to one of the four possible LED colors on avrsimon and then stored in U1 s internal EEPROM a non volatile storage container with individual byte addressing at the memory address equal to the current length of the sequence The game then plays the entire sequence that is currently in its EEPROM contiguously from address O until the end of the sequence is reached For more details on EEPROM handling see www nongnu org avr libc user manual group__avr__eeprom html The game then enters the simon_read_moves routine which waits for the player to begin replaying the sequence For each move in the sequence the corresponding address of the EEPROM is read and compared with
14. tune will welcome you Press any of the pushbuttons to start playing The game will generate a sequence of lights and sounds that you are to repeat starting first with a single element After the sequence has been presented simply press the button s corresponding to the LED that was illuminated and repeat the pattern The sequence length will increment each time you successfully repeat the pattern making the game increasingly more difficult as you go The maximum sequence length is 255 When your game is over a short tune will be played the correct LED in the sequence that you were supposed to have entered will be illuminated and your score will be given by a series of blinking LEDs The green LED corresponds to hundred the red LED to ten and the blue LED to one For example if you failed after a 13 element sequence the red LED will first blink once and then the blue LED will blink three times avrsimon has a few optional twists to make gameplay more fun and interesting for advanced players These special modes are selected by holding down one of the pushbuttons SW1 SW4 while first turning on the game multiple pushbuttons can be held down at one time to create various combinations e SW1 No Sound Quiet Mode No sounds are generated while in this mode making it perfect for gameplay late at night in a library conference session or classroom e SW2 Fast Mode This mode increases the speed of which the LED sequence is played an
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