Home

MODEL 104-AIO16-16E USER MANUAL

1. X X X X X X D1 DO The Board is capable of performing multiple data acquisitions of a single channel very quickly The board uses this ability to perform a unique mode of operation Oversampling Oversampling is a technique wherein the board will sample the current channel within the scan more than one time Oversampling of 1X 2X 8X and 16X are available Write 0x03 for 2X 0x00 for 8X 0x02 for 16X or 0x01 for the normal one conversion per channel Oversampling has no effect on Software Mode nor on Burst Mode operation 31 Manual 104 AlO16 16E Chapter 7 Connector Pin Assignments IDC 26 Pin Header Male 2 26 Connector P1 26 pin IDC header male Analog Inputs MUX DAC Outputs 16 Channel Single Ended Mode 8 Channel Differential Mode Pin Function Pin Function Pin Function Pin Function 1 A D Ch 0 Input 2 A D Ch 8 Input 1 A D Ch 0 Input 2 A D Ch 0 Input 3 Ground 4 A D Ch 9 Input 3 Ground 4 A D Ch 1 Input 5 A D Ch1 Input 6 Ground 5 A D Ch1 Input 6 Ground 7 A D Ch 2 Input 8 A D Ch 10 Input 7 A D Ch 2 Input 8 A D Ch 2 Input 9 Ground 10 A D Ch 11 Input 9 Ground 10 A D Ch 3 Input 11 A D Ch 3 Input 12 Ground 11 A D Ch 3 Input 12 Ground 13 A D Ch 4 Input 14 A D Ch 12 Input 13 A D Ch 4 Input 14 A D Ch 4 Input 15 Ground 16 A D Ch 13 Input 15 Ground 16 A D Ch 5 Input 17 A D Ch 5 Input 18 Gr
2. M 5V Single ended 10 DAC 0 0 10V Range 11 DAC 0 0 5V Range 12 DAC 1 0 10V Range 13 DAC 1 0 5V Range 14 3F unused Write each calibration constant to the correct Digital Calibration Potentiometer Refer to Chapter 6 Base B for more information on writing to the Digital Potentiometers Table C 1 Factory EEPROM Calibration Locations Remember that all of these steps are already encapsulated in a C language DOS compatible Calibration program that ships free with the board For the fastest way to write your own calibration program consider referring to the source code of the Calibration program 45 Manual 104 AlO16 16E Customer Comments If you experience any problems with this manual or just want to give us some feedback please email us at manuals accesio com Please detail any errors you find and include your mailing address so that we can send you any manual updates ACCES 1 0 PRODUCTS INC 10623 Roselle Street San Diego CA 92121 1506 Tel 858 550 9559 FAX 858 550 7322 www accesio com 46 Manual 104 AlO16 16E
3. 16 Program Counter 2 Read Counter 2 17 Set up Counter Control Register n a 18 19 Reset Digital I O to Input Mode 1A Scan Control 1 1B 1C 1D Master Reset 1E Scan Control 2 1F Configure OVERSAMPLING Addresses left blank in the table above are reserved for factory use and should not be accessed by user software programs Table 6 1 Register Definition Map 21 Manual 104 AlO16 16E Base Address 0 Start A D Conversion Read A D Data FIFO Writing any value to this address causes the A D to make one data acquisition and load it into the FIFO This is known as a Software Start Conversion command The channel acquired is the currently selected one in the A D Channel Scan Control register Please refer to the discussion in Base 2 for information on selecting the channels Reading two bytes consecutively from Base O amp Base 1 will retrieve the LSByte and MSByte of the data from the FIFO It is very important to avoid getting out of sync with the data so it is recommended you use 16 bit word reads instead of consecutive byte reads Reading a word value from this base address will automatically grab one conversion s data from the FIFO both bytes It is useful to always use 16 bit reads from this address to ensure the integrity of FIFO data The data is returned in 16 binary coded bits where the hexadecimal value FFFF corresponds to maximum input voltage and hexadecimal 0000 corresponds to minimum input vol
4. 5V or 10V as per range selection As an example to load 7FF midrange into DACO the following writes are required 011111111111 in binary a value of either 2 5V or 5 0V depending on range selected The value 7FF is Write Value Description 1 1xxxxx01 81 Start Bit Always write 81 as the 1 byte 2 Oxxxxx11 03 DAC selection Write 03 for DACO 83 for DAC1 3 1xxxxx11 83 DAC selection Write 83 for DACO 03 for DAC1 4 Oxxxxx11 03 Spacer Bit Always write 03 as the 4 byte 5 Oxxxxx11 03 MSB of data Bit 7 should be 1 or 0 based on the D11 bit of data to be output Always set D1 and DO to 1 6 1xxxxx11 83 Bit 7 should be bit D10 of data Always set D1 and DO to 1 7 1xxxxx11 83 Bit 7 should be bit D9 of data Always set D1 and DO to 1 8 1xxxxx11 83 Bit 7 should be bit D8 of data Always set D1 and DO to 1 9 1xxxxx11 83 Bit 7 should be bit D7 of data Always set D1 and DO to 1 10 1xxxxx11 83 Bit 7 should be bit D6 of data Always set D1 and DO to 1 11 1xxxxx11 83 Bit 7 should be bit D5 of data Always set D1 and DO to 1 12 1xxxxx11 83 Bit 7 should be bit D4 of data Always set D1 and DO to 1 13 1xxxxx11 83 Bit 7 should be bit D3 of data Always set D1 and DO to 1 14 1xxxxx11 83 Bit 7 should be bit D2 of data Always set D1 and DO to 1 15 1xxxxx11 83 Bit 7 should be bit D1 of data Always set D1 and DO to 1 16 1xxxxx11 83 LSB of data Bit 7 should be bit DO
5. 81 Bit 7 should be bit D2 of address Always set DO to 1 8 Oxxxxxx1 01 Bit 7 should be bit D1 of address Always set DO to 1 9 1xxxxxx1 81 LSB of address Bit 7 should be 1 or 0 based on the DO bit of address to be written Always set DO to 1 10 1xxxxxx1 81 MSB of data Bit 7 should be 1 or 0 based on the D15 bit of address to be written Always set DO to 1 11 Oxxxxxx1 01 Bit 7 should be bit D14 of data Alwways set DO to 1 12 1xxxxxx1 81 Bit 7 should be bit D13 of data Always set DO to 1 13 Oxxxxxx1 01 Bit 7 should be bit D12 of data Always set DO to 1 14 1xxxxxx1 81 Bit 7 should be bit D11 of data Always set DO to 1 15 Oxxxxxx1 01 Bit 7 should be bit D10 of data Always set DO to 1 16 1xxxxxx1 81 Bit 7 should be bit D9 of data Always set DO to 1 17 Oxxxxxx1 01 Bit 7 should be bit D8 of data Always set DO to 1 18 Oxxxxxx1 01 Bit 7 should be bit D7 of data Always set DO to 1 19 1xxxxxx1 81 Bit 7 should be bit D6 of data Always set DO to 1 20 Oxxxxxx1 01 Bit 7 should be bit D5 of data Always set DO to 1 21 1xxxxxx1 81 Bit 7 should be bit D4 of data Always set DO to 1 22 Oxxxxxx1 01 Bit 7 should be bit D3 of data Always set DO to 1 23 1xxxxxx1 81 Bit 7 should be bit D2 of data Always set DO to 1 24 Oxxxxxx1 01 Bit 7 should be bit D1 of data Always set DO to 1 25 1xxxxxx1 81 LSB of data Bit 7 should be 1 or O based on the DO bi
6. 8253 Timer 804 2 Keyboard Controller CMOS RAM NMI Mask Reg RT Clock DMA Page Register 8259 Slave Interrupt Controller 8237 DMA Controller 2 Math Coprocessor Math Coprocessor Fixed Disk Controller 2 Fixed Disk Controller 1 Game Port Bus Mouse Alt Bus Mouse Parallel Printer EGA EGA EGA GPIB AT Serial Port Serial Port reserved reserved Hard Disk XT Floppy Controller 2 Parallel Printer SDLC SDLC MDA Parallel Printer VGA EGA CGA Serial Port Floppy Controller 1 Serial Port Table 3 2 Hex Ranges for Standard Computers 11 Manual 104 AlO16 16E IRQ Configuration This board can be software enabled to generate an IRQ when the A D FIFO becomes half full or on the end of a scan The FIFO half full IRQ is one method of taking A D data off the board quickly The End of Scan IRQ allows software to be notified after a full scan of data has be acquired so that this data can be read quickly See Chapter s 4 and 6 for more information on the A D IRQ s and taking data off the board The selection of the Interrupt IRQ to be used is made by selecting one of the IRQ jumpers on the board These jumpers are located adjacent to the 104 connector in three groups The location of these jumpers is shown in the Option Selection map as well as in the Setup Program provided with the board Place a jumper on the posts corresponding to the IRQ you wish to select If you do not intend on using the A D Data FI
7. Aa dee A IDC 8 Pin Header Male 21 DIO10 22 Ground 2 Ga 8 23 DIO11 24 Ground 0 7 25 DIO 12 26 Ground Connector P3 External Power 8 pin Male IDC Header 27 DIO13 28 Ground Pin Signal Pin Signal 29 DIO14 30 Ground 1 Ground Ground 31 DIO 15 32 Ground 33 CtrO Out 34 Ground Ground 12V 2 Ground 4 12V 6 8 NIOJ QW 35 Ground 36 Delayed ExtTrig Ground Ground 37 Ground 38 ScanStart 39 Reserved 40 Ctr 2 Out The board can take 12V power from the PC 104 bus an external source or an optional DC DC converter If the DC DC converter is installed on the board the two jumpers next to P3 should not be installed and their posts may be missing If no DC DC converter is present the jumpers should be installed in their right positions to take 12V power from the PC 104 bus or the left positions toward the edge of the board to take 12V power from an external source provided via P3 Refer to the Option Selection Map in Chapter 3 for more information 33 Manual 104 AlO16 16E Appendix A Technical Specifications A D Inputs Sampling rate A D FIFO Accuracy Ranges Selections of Number of Channels Resolution Input Impedance Overvoltage protection Common Mode Rejection Integral Nonlinearity Conversion Modes Oversampling Modes Counter Timers Type Clock Input Frequ
8. DIO3 DIO2 DIO1 DIOO Reading from Base 10 will return the digital data available on pins DIOO 7 Writing a value to Base 10 will configure the bits as outputs and output the value to the pins Once the bits have been configured as outputs subsequent reads return the most recently written value You can reset all DIOs DIOO 15 to the read function by writing to Base 19 Base Address 11 Digital I O Bits 8 15 Bit 7 Bit 6 Bits Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Read Write DIO15 DIO14 DIO13 DIO12 DIO11 DIO10 DIO9 DIO8 Reading from Base 11 will return the digital data available on pins DIO8 15 Writing a value to Base 11 will configure the bits as outputs and output the value to the pins Once the bits have been configured as outputs subsequent reads return the most recently written value You can reset all DIOs DIOO 15 to the read function by writing to Base 19 Base Address 14 through Base Address 17 Counter Programming For detailed information on programming the 8254 Counter Timer device please refer to Appendix B Counter 0 is used as a frequency generator with its clock input being 10MHz This allows one to generate a desired frequency of 10MHz n where 1 lt n lt 65536 Counter 0 s output resides on connector P2 pin 33 29 Manual 104 AlO16 16E When using Timed Scan Start acquisition it is important that the load value in Counter 1 and 2 be sufficient to give the A D circuit time to f
9. Scan Start Step 5 1 Connect External Scan Start Signal across pin 37 GND and pin 38 HOT See Chapter 3 Power Off Step 5 2 Set Channel Please see Software mode Step 1 1 for information Step 5 3 Set Gain Code Please see Software mode Step 1 2 for information Step 5 4 Configure Oversampling defaults to x1 Please see Timed Scan Start Step 3 5 for information Step 5 5 Enable External Scan Start Write 0x10 to Base 1A and Write 0x40 to Base 1E Step 5 6 External Start Signal may now be started Step 5 7 READ DATA FAST See Burst Mode Step 2 4 Step 5 8 Stop Data Acquisition Write 0x00 to Base 1A and Write 0x00 to Base 1E 18 Manual 104 AlO16 16E READ DATA FAST The board contains a 4096 byte A D Data FIFO configured as a 2048 sample FIFO each sample is 16 bits The FIFO provides two status bits useful when taking data from the board First a Data FIFO Half DFH bit is available This bit indicates the FIFO is now half full This bit can also generate an IRQ when DFH IRQ is enabled An EMPTY bit is provided which indicates the FIFO contains no data Conversely if there is any data in the FIFO the EMPTY bit will not be true Using combinations of these two bits and the DFH IRQ allows several fast and efficient methods of taking the data from the FIFO Perhaps the simplest method of taking data is to read one sample at a time using a 16 bit Word Read of Base 0 In this mode you determine when to read the samp
10. Start Each of these three modes require this bit to be set Refer to the Base 1E section below for further information on enabling the aforementioned modes Always program Counters 1 and 2 before enabling Base 1A bit 4 and Base 1E bit 6 only applies to modes Timed Scan Start and Delayed Timed Scan Start Remember to reset both Base 1A bit 4 and Base 1E bit 6 when disabling Timed Scan Start Delayed Timed Scan Start or External Scan Start Base Address 1E Enable Data Acquisition Write Only Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit O x Enable X X X X X x Disable After bit 4 has been set in base 1A See above bit 6 must be set in base 1E For modes Timed Scan Start and External Scan Start this bit is written by software However Delayed Timed Scan Start sets this bit when the delayed external trigger pin 36 See Figure 3 1 goes low Therefore the Delayed Timed Scan Start does not need software to set this bit Always program Counters 1 and 2 before enabling Base 1A bit 4 and Base 1E bit 6 only applies to modes Timed Scan Start and Delayed Timed Scan Start 30 Manual 104 AlO16 16E Remember to reset both Base 1A bit 4 and Base IE bit 6 when disabling Timed Scan Start Delayed Timed Scan Start or External Scan Start Base Address 1F Configure Oversampling Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Write
11. Until the count is loaded into the counter itself it cannot be read RW1 RWO Read Write command M2 M1 MO Counter mode BCD BCD 0 is binary mode otherwise counter is in BCD mode 38 Manual 104 AlO16 16E If both STA and CNT bits in the readback command byte are set low and the RW1 and RWO bits have both been previously set high in the counter control register thus selecting two byte reads then reading a selected counter address location will yield 1st Read Status byte 2nd Read Low byte of latched data 3rd Read High byte of latched data After any latching operation of a counter the contents of its hold register must be read before any subsequent latches of that counter will have any effect If a status latch command is issued before the hold register is read then the first read will read the status not the latched value 39 Manual 104 AlO16 16E Appendix C Calibration This board features digitally controlled potentiometers which are used to adjust the gain and offset of the A D function and the gain of the DAC function This allows both the analog inputs and outputs to be calibrated from software in the field In order to obtain accurate data the proper values must be loaded into the digital potentiometers each time the board is powered If no constants are loaded the potentiometers will power on to the center of their ranges which will result in a non or poorly calibrated situation When the board ships from th
12. Write 0x40 to Base 1E Setting these two bits will cause the board to initiate one scan of A D data each timeout occurring on Counter 2 It is important that the Start trigger does not occur during a scan When using the counter you must have a long enough timeout period loaded in Counters 1 2 that the board has time to complete Oversample number of conversions on as many channels as you have selected at Base 2 Once this step is performed and the counters have timed out a scan will start READ DATA FAST See Burst Mode Step 2 4 Disable Timed Mode Write 0x00 to Base 1A and Write 0x00 to Base IE 4 Delayed Timed Scan Start Step 4 1 Jumper Pins 38 and 40 Connect External Delayed Signal To Pins 35 GND and 36 HOT See Chapter 3 Power Off Step 4 2 Set Channel Please see Software mode Step 1 1 for information Step 4 3 Set Gain Code Please see Software mode Step 1 2 for information Step 4 4 Configure Counters 1 2 using periodic timed scans using the output of Counter 2 Please see Timed Scan Start Step 3 4 for information Step 4 5 Configure Oversampling defaults to x1 Please see Timed Scan Start Step 3 5 for information Step 4 6 Enable Delay mode Write 0x10 to Base 1A Step 4 7 Data started by External Trigger see Figure 3 1 for connection information Step 4 8 READ DATA FAST See Burst Mode Step 2 4 Step 4 9 Stop Data Acquisition Write 0x00 to Base 1A and Write 0x00 to Base 1E 5 External
13. adjusting the gain a known voltage 5 below the maximum input of the A D converter will result in a good reading across the entire range Alternately calibrating the A D to a voltage near the actual application voltage you ll be expecting in your system results in perfect readings in your specific system In the vast majority of cases either calibration method will result in correct data Continuing our example from above when calibrating the 0 10V range a voltage near 10 Volts is recommended we ll use 9 5 Volts as our Known Voltage Using a calibrated voltage source apply your known voltage to the inputs of at least one A D channel The other channels should not have signals connected or should be grounded To connect a known voltage to channel 0 connect the voltage to P2 Pin 1 and use P2 Pin 3 as the reference ground Acquire the voltage using the A D converter See step 1 1 2 Adjust the value in the digital calibration potentiometer for the A D until the voltage read by the A D matches the input voltage Many methods of determining values for the digital calibration potentiometer exist One possible method Set the Pot to 0 and take a reading If the result is off scale reading 0000 or FFFF counts set the Pot to FF and take another reading One of these two readings will not be railed off scale Increment or decrement the Pot load value until the data read from the A D reads the Known Voltage To convert from counts to voltage use
14. and BIP UNI jumper selected ranges so a total of 4 A D Input calibration data pairs are used Consult the provided calibration program or sample code for information on the locations in the EEPROM used to store the calibration data Although the EEPROM is intended to contain calibration data it is unlikely your program will need to keep calibration data for the ranges you are not going to use In this case you can use those locations in the EEPROM for your own purposes 25 Manual 104 AlO16 16E Writing to the EEPROM Base A In order to write to the EEPROM a start bit must be transmitted then the Write opcode 2 bits 01 followed by the address location of the data to be loaded into the EEPROM 6 bits MSB first followed by the data 16bits MSB first Then the transmission is ended with 0 Therefore to write a value of aa55 to location 5 you would perform the following 26 writes Write Value Description 1 1xxxxxx1 81 Start Bit Always write 81 as the 1 byte 2 Oxxxxxx1 01 opcode bit 1 always write 01 as 2 byte for EEPROM writing 3 1xxxxxx1 81 opcode bit 0 always write 81 as 3 byte for EEPROM writing 4 Oxxxxxx1 01 MSB of address Bit 7 should be 1 or O based on the D5 bit of address to be written Always set DO to 1 5 Oxxxxxx1 01 Bit 7 should be bit D4 of address Always set DO to 1 6 Oxxxxxx1 01 Bit 7 should be bit D3 of address Always set DO to 1 7 1xxxxxx1
15. each time the board is powered Consult Appendix C Calibration for information on how to determine and load appropriate settings 14 Manual 104 AlO16 16E Chapter 4 Analog Digital Converter Operation The A D circuitry on this board forms a very powerful and flexible framework on which you can build a broad array of data acquisition applications The rest of this chapter is broken down into several sections The first section is an Overview which will introduce you to the most common modes of using the A D This will be followed by a Breakdown of the steps recommended to use each of the four modes Next a Step By Step walkthrough is provided Steps are numbered consistently between the three sections so you can easily flip between them to build an understanding of the process Following these discussions of the A D operational modes is some explanation of the various methods of reading the A D off the board Before using any Analog function of the board make sure you ve configured the jumpers as described in Chapter 3 Also make sure the proper calibration constants have been loaded into the calibration potentiometers using the procedures discussed in Appendix C Also Pins 35 through 40 provide the method of connecting triggers and scan start signals and proper configuration of these pins is important to success in using each mode See the detailed mode descriptions for more information Overview A D Operational Modes Five modes of A D o
16. eee 45 4 Manual 104 AlO16 16E Chapter 1 Introduction This board is a high speed 16 bit resolution Analog to Digital A D multifunction board featuring an excellent price performance value It is very useful for precision PC 104 based data acquisition control or signal analysis in applications such as standalone environmental test stations compact production test equipment portable testers avionics and others In addition to direct data transfers the board s ability to trigger the A D in real time assures synchronized sampling that is unaffected by other computer operations This is an essential requirement for signal vibration and transient analysis where high data rates must be sustained for short periods of time This high speed sampling rate is supported by a FIFO for reducing processor overhead and is filtered for an extremely quiet front end Sixteen parallel bits of digital I O and two 12 bit D A outputs allow for a complete high performance data acquisition solution Analog In 16 Single Ended or 8 Differential 16 Bit Analog Inputs are provided Any single channel can be acquired at 250 000 samples second and any range of channels can be acquired at 250 000 samples second divided by the number of input channels your taking data on The Analog Inputs feature hardware I software selectable ranges of 0 1V 0 2V 0 5V 0 10V 0 5V 1V 2V 2 5V 5V and 10V All the data from the A D is placed in a 2KSample FIFO for the
17. fastest possible data transfer Conversions can be started using software commands an internal burst mode or with an external trigger via a pin at the connector Analog Out Two 12 Bit Digital to Analog converter DAC outputs are provided Output ranges of 0 5V and 0 10V are field selectable with jumpers per channel Digital I O 16 Buffered Digital Input Outputs are provided All 16 lines may be programmed as inputs or outputs or 8 lines may be inputs while the other 8 are outputs All lines are pulled up via resistors to 5 Volts Counter Timer The board uses an 82C54 Programmable Interval Timer 3 sixteen bit counters The counters are used to generate frequencies Counter 0 and time various aspects of the A D conversion process Counters 1 2 If you are using non counter timed A D modes Counter 2 becomes available for frequency generation Consult Chapter 4 Chapter 6 and Appendix B for more information on the A D programming and the counter itself Calibration This board features digitally controlled potentiometers which are used to adjust the gain and offset of the A D function and the gain of the DAC function This allows both the analog inputs and outputs to be calibrated from software in the field In order to obtain accurate data the proper values must be loaded into the digital potentiometers each time the board is powered If no constants are loaded the potentiometers will power on to the center of their ranges wh
18. move both signal wires in the same direction leaving the difference in potential unchanged this is referred to as common mode rejection CMR Differential CMR improves signal to noise characteristics but reduces system input channel count For best results a ground wire should be supplied to limit the system s Common Mode The maximum common mode an input can reject in this manner is defined in the Specifications If no external ground wire is available and two signal wires are floating then two pull down resistors at the inputs of the PGA onboard will keep the common mode within 10V 13 Manual 104 AlO16 16E The gain of the Programmable Gain Amplifier may also be set through software If not programmed the default gain is x1 The board has the capability of storing different gains for A D input channels 0 F There are two addresses used in setting up the gain channel storage base 4 and base 5 The base 4 address is used for setting up the four lower channels 0 through 3 The base 5 address is used for setting up the four upper channels 4 through 7 Channels 8 F use channels 0 7 stored gains respectively Loading Calibration Constants The gain and offset of the signal conditioning circuitry are adjusted by means of digital potentiometers If constants are not loaded the potentiometers will be set to the center of their ranges by default Therefore for maximum accuracy appropriate settings should be entered into them
19. the following equation Volts Span Counts MaxCounts Offset MaxCounts on a 16 bit A D is 65536 and Span and Offset vary with the selected range In any unipolar range Offset is zero and the Span is equal to the maximum voltage In any bipolar range the Span is equal to the maximum input voltage minus the minimum input voltage and Offset is half of this value For example 5Volt range has a Span of 10V and an Offset of 5V If the A D reads FFE9 counts on a 0 10V range the voltage being indicated is 10 FAE9 FFFF 0 or 9 801 Volts Store the value from the digital calibration potentiometer into a spot in the EEPROM for use on the next and subsequent board initializations The correct spot in EEPROM varies with the A D range and single ended differential selection being calibrated We recommend you use the same locations as our provided Calibration program drivers and samples as shown in Table C 1 below For example if you are calibrating the Gain of the 0 10 Volts Single Ended setting of the board we recommend you write the calibration Potentiometer value into the D location of the EEPROM Write the value using the procedure outlined in the description of Base A in Chapter 6 Step 2 Write the Calibration Constants into the Calibration Potentiometers Step 2 applies to both DAC and A D Calibration Step 1 involved applying or measuring voltages connecting pins and sources etc Step 1 only needs to be performed if the data from the A D appear
20. the selected counter to count in binary BCD 0 or BCD BCD 1 37 Manual 104 AlO16 16E READING AND LOADING THE COUNTERS If you attempt to read the counters on the fly when there is a high input frequency you will most likely get erroneous data This is partly caused by carries rippling through the counter during the read operation Also the low and high bytes are read sequentially rather than simultaneously and thus it is possible that carries will be propagated from the low to the high byte during the read cycle To circumvent these problems you can perform a counter latch operation in advance of the read cycle To do this load the RW1 and RW2 bits with zeroes This instantly latches the count of the selected counter selected via the SC1 and SCO bits in a 16 bit hold register An alternative method of latching counter s which has an additional advantage of operating simultaneously on several counters is by use of a readback command to be discussed later A subsequent read operation on the selected counter returns the held value Latching is the best way to read a counter on the fly without disturbing the counting process You can only rely on directly reading counter data if the counting process is suspended while reading by bringing the gate low or by halting the input pulses For each counter you must specify in advance the type of read or write operation that you intend to perform You have a choice of loading reading a the h
21. word at the specified address Read 15 D7 contains bit D1 from the word at the specified address Read 16 D7 contains bit DO from the word at the specified address Write Oxxxxxx0 00 End Always Write 00 as the last step For ease of reference the bits which can change are typeset in bold 27 Manual 104 AlO16 16E Base Address B Calibration Data Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Data x x x x x x SClock The Software Master CD contains sample programs demonstrating the use of the calibration potentiometers in a variety of languages including a driverlet which encapsulates the complexities of the process Using this driverlet is as simple as passing the M and B correction values for A D calibration or the DAC number and M correction values for D A calibration to our functions It is highly recommended that you use the provided source code as a basis for your own programs The board contains 4 digital potentiometers used to calibrate the device The four calibration corrections provided are A D Offset 00 A D Gain 01 Gain for DACO 10 and DAC1 11 These four corrections are internally addressed 0 1 2 and 3 Each calibration correction consists of a value from 0 255 8 bits corresponding to the internal value of the digital potentiometer A D Offset corresponds to the B in a Y mX B equation A D Gain is the m term of the same equation D
22. 1 2 using periodic timed scans using the output of Counter 2 17 Manual 104 AlO16 16E Step 3 5 Step 3 6 Step 3 7 Step 3 8 When using periodically timed scans the counters are configured in Mode 2 with a load value appropriate to the timing you want The input frequency to Counter 1 is 10MHz and the input to Counter 2 is the output of Counter 1 This method of combining Counters 1 and 2 gives a 32 bit counter allowing for finer granularity when generating a scan start rate The equation to determine the needed load value for the 32 bit Counter 1 2 is 10 000 000 ScanRate Hz For example if you want scans to start every 15 milliseconds your equation is 10 000 000 1 0 015 10 000 000 66 67 150 000 This value must then be loaded into the two 16 bit counters The simplest method to do this would be to take the square root of 150 000 and load this value into both counters However because the square root of 150 000 is not an integer one must find two integer factors of 150 000 each smaller than 65 535 and larger than 1 3 and 50 000 work fine load Counter 1 with 3 and Counter 2 with 50 000 and your scan rate is set at 66 67Hz See Appendix B for more information on loading the counters Configure Oversampling defaults to x1 Write to Base 1F allows x1 x2 x8 or x16 samples per channel to be acquired before changing to the next selected channel See Chapter 6 Base IF Enable Timed Mode Write 0x10 to Base 1A and
23. AC Gain represents m in the equation Y mX The nature of the DAC circuitry eliminates the need to provide offset B calibration The value you load into these calibration potentiometers you normally read from the EEPROM and write here during program initialization and only needs to be written once per power on cycle To load one of the calibration correction values you must write the address of the correction you wish to load the 8 bit value you wish to load and an End byte Similar to the operation of the DAC and EEPROM the calibration correction values are loaded serially into the digital potentiometers in the board The steps are outlined in the table below Therefore to load a value of 4F into the A D Gain potentiometer the following writes are performed Write Value Description 1 Oxxxxxx1 01 These two bits are the address of the potentiometer to write 00 is A D offset S 01 is gain 10 is DACO gain 11 is DAC1 gain Write 1 is the MSB Write 2 is 2 1xxxxxx1 81 the LSB 3 Oxxxxxx1 01 MSB of data Bit D7 of Write 3 should be the D7 bit of the calibration correction value you are loading 1xxxxxx1 81 D7 should be bit D6 of the calibration value Oxxxxxx1 01 D7 should be bit D5 of the calibration value Oxxxxxx1 01 D7 should be bit D4 of the calibration value 1xxxxxx1 81 D7 should be bit D3 of the calibration value oo d O Qm A 1xxxxxx1 81 D7 should be bit D2 of the calibration v
24. ACCES 1 0 PRODUCTS INC 10623 Roselle Street San Diego CA 9212 858 550 9559 Fax 858 550 7322 contactus accesio com www accesio com MODEL 104 AlO16 16E USER MANUAL FILE M104 AlO16 16E C4c Notice The information in this document is provided for reference only ACCES does not assume any liability arising out of the application or use of the information or products described herein This document may contain or reference information and products protected by copyrights or patents and does not convey any license under the patent rights of ACCES nor the rights of others IBM PC PC XT and PC AT are registered trademarks of the International Business Machines Corporation Printed in USA Copyright 2006 by ACCES I O Products Inc 10623 Roselle Street San Diego CA 92121 1506 All rights reserved WARNING ALWAYS CONNECT AND DISCONNECT YOUR FIELD CABLING WITH THE COMPUTER POWER OFF ALWAYS TURN COMPUTER POWER OFF BEFORE INSTALLING A CARD CONNECTING AND DISCONNECTING CABLES OR INSTALLING CARDS INTO A SYSTEM WITH THE COMPUTER OR FIELD POWER ON MAY CAUSE DAMAGE TO THE l O CARD AND WILL VOID ALL WARRANTIES IMPLIED OR EXPRESSED 2 Manual 104 AlO16 16E Warranty Prior to shipment ACCES equipment is thoroughly inspected and tested to applicable specifications However should equipment failure occur ACCES assures its customers that prompt service and support will be available Any equipment originally manufactured by AC
25. CES which is found to be defective will be repaired or replaced subject to the following considerations Terms and Conditions If a unit is suspected of failure contact ACCES Customer Service department Be prepared to give the unit model number serial number and a description of the failure symptom s We may suggest some simple tests to confirm the failure We will assign a Return Material Authorization RMA number which must appear on the outer label of the return package All units components should be properly packed for handling and returned with freight prepaid to the ACCES designated Service Center and will be returned to the customer s user s site freight prepaid and invoiced Coverage First Three Years Returned unit part will be repaired and or replaced at ACCES option with no charge for labor or parts not excluded by warranty Warranty commences with equipment shipment Following Years Throughout your equipment s lifetime ACCES stands ready to provide on site or in plant service at reasonable rates similar to those of other manufacturers in the industry Equipment Not Manufactured by ACCES Equipment provided but not manufactured by ACCES is warranted and will be repaired according to the terms and conditions of the respective equipment manufacturer s warranty General Under this Warranty liability of ACCES is limited to replacing repairing or issuing credit at ACCES discretion for any products which are proved to be defec
26. Differential Channels Bit1 0 Bipolar Operation Bit 2 0 High Gain Jumpered Bit3 0 DACB range 0 to 10V Bit4 0 DACArange 0 to 10V Bit 5 0 FIFO is less than half full Bit6 0O FIFO is not full Bit 7 0 FIFO is not empty 16 Single Ended Channels Unipolar Operation Low Gain Jumpered DAC B range 0 to 5V DAC A range 0 to 5V FIFO is at least half full FIFO is full FIFO is empty m m m m m m m m 23 Manual 104 AlO16 16E Base Address 9 DAC Outputs Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Write Data X X Load SClock DAC data loading Write The Software Master CD contains sample programs demonstrating the use of the DAC in a variety of languages including a driverlet which encapsulates the complexities of the process Using this driverlet is as simple as passing the DAC number and voltage you want to a function It is highly recommended that you use the provided source code as a basis for your own programs This chip is a dual 12 bit DAC with a serial interface In order to load a value into the DAC and have it converted to an analog output 18 successive writes must be made to base address 9 These writes are used to create the signals needed to communicate to the DAC The DACs are jumper configured as 0 5 or 0 10V outputs Writing a code of 0 results in O Volts writing FFF results in either
27. FINDBASE software utility provided on the CD with your board will help you select a base address that does not conflict with other assignments This board requires a block of 32 addresses 20 hex In order to configure the desired address the hexadecimal address must be converted to a binary representation For example as illustrated below jumper selection corresponds to hex 2C0 or binary 10 110x xxxx The Xxxxx represents address lines A4 through AO used on the board to select individual registers as described in Chapter 6 Programming of the manual Hex Representation C Conversion Factors 2 1 8 4 2 Binary Representation 1 0 1 1 0 Jumper Installed NO YES NO NO YES Jumper Label A9 A8 A7 A6 A5 Table 3 1 Address Selection and Hex Conversions Review the Address Selection Table carefully before selecting the board address If you have doubts concerning available addresses in your particular computer use the FINDBASE utility provided to determine available addresses 10 Manual 104 AlO16 16E HEX RANGE USAGE 000 00F 020 021 040 043 060 06F 070 07F 080 09F OAO OBF 0C0 ODF OFO OF1 OF8 OFF 170 177 1F0 1F8 200 207 238 23B 23C 23F 278 27F 2B0 2BF 2C0 2CF 2D0 2DF 2E0 2E7 2E8 2EF 2F8 2FF 300 30F 310 31F 320 32F 370 377 378 37F 380 38F 3A0 3AF 3B0 3BB 3BC 3BF 3C0 3CF 3D0 3DF 3E8 3EF 3F0 3F7 3F8 3FF 8237 DMA Controller 1 8259 Interrupt
28. FO Half Full IRQ do not install a jumper on any IRQ pins DAC Configuration This board provides two analog outputs Each analog output is adjusted by output calibration circuitry including a digital potentiometer The DAC and digital calibration potentiometers are serial devices with data being entered bit by bit Although the details of writing bit by bit are described in Chapter 6 the DAC data will be loaded using a software subroutine In order to obtain correct analog outputs the following operations must be performed 1 The desired output ranges must be selected by means of jumper selections on the board There are two jumpers labeled DA5 and DB5 respectively To select the range for channel A a jumper needs to be installed at DAS To select the 5 Volt range the jumper should be in the position away from the 104 connector To select the 10 Volt range the jumper should be in the position nearer the 104 connector To select the range for channel B a jumper needs to be similarly installed at DB5 The Setup Program and Option Selection Map provide convenient references for setting these options 2 The correct calibration constants must be loaded into the digital potentiometers that adjust the output circuitry This operation is described in Appendix C Calibration Frequency Generator Configuration This board provides a frequency generator output Counter 0 The input clock to Counter 0 is 10MHz and therefore allows a frequency o
29. OM to be Read Always set DO to 1 5 Oxxxxxx1 01 Bit 7 should be bit D4 of address Always set DO to 1 6 Oxxxxxx1 01 Bit 7 should be bit D3 of address Always set DO to 1 7 1xxxxxx1 81 Bit 7 should be bit D2 of address Always set DO to 1 8 Oxxxxxx1 01 Bit 7 should be bit D1 of address Always set DO to 1 9 Oxxxxxx1 01 LSB of address Bit 7 should be 1 or O based on the DO bit of address to be read Always set DO to 1 Read 1 Bit D7 of this Read returns the Most Significant Bit D15 of the 16 bit data stored at the address specified in writes 4 through 9 Read 2 D7 contains bit D14 from the word at the specified address Read 3 D7 contains bit D13 from the word at the specified address Read 4 D7 contains bit D12 from the word at the specified address Read 5 D7 contains bit D11 from the word at the specified address Read 6 D7 contains bit D10 from the word at the specified address Read 7 D7 contains bit D9 from the word at the specified address Read 8 D7 contains bit D8 from the word at the specified address Read 9 D7 contains bit D7 from the word at the specified address Read 10 D7 contains bit D6 from the word at the specified address Read 11 D7 contains bit D5 from the word at the specified address Read 12 D7 contains bit D4 from the word at the specified address Read 13 D7 contains bit D3 from the word at the specified address Read 14 D7 contains bit D2 from the
30. alue 9 1xxxxxx1 81 D7 should be bit D1 of the calibration value 10 1xxxxxx1 81 D7 should be bit DO of the calibration value 11 Oxxxxxx1 00 End Always Write 00 as the last step For ease of reference the bits which can change are typeset in bold 28 Manual 104 AlO16 16E Base Address C Interrupt Enable Write Only Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit O Xx x X Enable Disable X X X Enable Disable DFH EOS The selection of the IRQ used to transmit the interrupt is made by jumper selection on the board This selection is described in Chapter 3 There are two possible IRQ s to enable Data FIFO Half DFH and End of Scan EOS DFH occurs when the data FIFO reaches half full giving you time to take the data out of the FIFO before it reaches full when the FIFO becomes full A D conversions are paused EOS occurs when a scan has completed a data conversion on the last channel within the scan This allows a scan of data to be read immediately after the last channel in the scan has been sampled It is important that only one IRQ be enabled at a time Behavior might become unpredictable otherwise Writing 0x01 enables the EOS IRQ and Writing 0x10 enables the DFH IRQ Writing 0x00 disables IRQ s Base Address 10 Digital I O Bits 0 7 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Read Write DIO7 DIO6 DIOS DIO4
31. another scan can be started 15 Manual 104 AlO16 16E Breakdown A D Operational Modes The following describes the five modes of operation in more detail 1 Software 1 1 Set Channel Scan Limits Write to Base 2 1 2 Set Gain Code Word Write to Base 4 1 3 Start Conversion by writing to Base 0 1 4 Wait for FIFO not empty Read Base 8 Bit 7 low 1 5 Read Data Word Read Base 0 1 6 Until done Burst 2 1 Set Burst Channel Write to Base 2 lower nybble 2 2 Set Gain Code Word Write to Base 4 2 3 Start Burst Write 0x01 to Base 3 2 4 READ DATA FAST 2 5 Disable Burst Write 0x00 to Base 3 Timed Scan Start 3 1 Jumper Pins 38 and 40 See Chapter 3 Power Off 3 2 Set Channel Scan Limits Write to Base 2 3 3 Set Gain Code Word Write to Base 4 3 4 Configure Counters 1 and 2 Base 14 17 3 5 Configure Oversampling defaults to x1 Write to Base 1F 3 6 Enable Timed Mode Write 0x10 to Base 1A and Write 0x40 to Base 1E 3 7 READ DATA FAST 3 8 Disable Timed Mode Write 0x00 to Base 1A and Write 0x00 to Base 1E Delayed Timed Scan Start 4 1 Jumper Pins 38 and 40 Connect External Delayed Signal to Pins 35 and 36 See Chapter 3 Power Off 4 2 Set Channel Scan Limits Write to Base 2 4 3 Set Gain Code Word Write to Base 4 4 4 Configure Counters 1 and 2 Base 14 17 4 5 Configure Oversampling defaults to x1 Write to Base 1F 4 6 Enable Delay
32. at Base 8 Chapter 6 The correct spot in EEPROM varies with the DAC number being calibrated and the currently selected range see note 1 Please note you could use any location in the EEPROM you want as long as you always use the same location We recommend you use the same locations as our provided Calibration program drivers and samples as shown in Table C 1 below Step By Step Calibrating the DACs Now lets describe these steps in detail 1 1 Output a known value to the DAC You should determine the maximum range of the DAC using Base 8 see Chapter 6 Pick a value approximately 5 lower than this maximum By using a value lower than the maximum you avoid calibrating off the end of the range Alternately choose the voltage most likely to be output by your application in your own use For example if you re going to be using primarily voltages near 6 2 Volts you may want to calibrate it at that voltage Just substitute whatever voltage you choose in the math that follows Output this value to the DAC using the process described at Base 9 For example if your DAC is jumpered for the 0 10 Volt output range a value of 9 5 Volts 95 of 10 Volts would be a good choice Convert this voltage to a 12 bit digital count value Counts Volts MaxVolts MaxCounts so Counts 9 5 10 2412 1 0 95 4095 3890 25 Only a 12 bit integer numbers can be written to the DAC so we ll use 3890 as our count value Thi
33. cedure Step 1 Determine the calibration constants Step 2 Write the calibration constants into the calibration potentiometers Step 1 only needs to be performed if the board s data begins to appear out of calibration A good rule of thumb is to determine new calibration constants every six to twelve months of regular use If your environment undergoes frequent environmental changes more frequent calibration may be indicated When the board ships from the factory it already has a valid set of calibration constants preloaded into the EEPROM for your immediate use Step 2 writing the calibration constants into the digital calibration potentiometers must occur each time the board is powered up or reset Typically each time your program executes you ll write these values even if the program was run before Many devices using digital potentiometers require the software to load the calibration coefficients from a file on disk matching the file to the board based on a manually entered serial number or some similarly complex method This board instead contains EEPROM to store the calibration constants This makes it very simple the board remembers its own constants there s no need for a file on disk or serial number lookup databases etc The details are different between A D calibration and DAC calibration and are discussed separately below 40 Manual 104 AlO16 16E Breakdown Calibrating the DACs DAC calibration is very simple and
34. could select either GNH Bipolar or GNL Bipolar although GNH Bipolar would be simpler from a software perspective as the software programmable gain selection defaults to 0 the correct value for this range 1 The maximum span of the A D circuitry is selected by choosing the GNH high gain or GNL low gain jumpers located at the right edge of the board Note that there are two jumpers that must be installed in parallel one beside the other Another pair of jumpers must be installed to determine whether the ranges are unipolar e g 0 10V or bipolar e g 5V These jumpers are located above the gain jumpers at the right edge of the board The pair must be installed in parallel one beside the other 2 The Diff SE mode of the multiplexer and the A D circuitry is selected by installing two jumpers Two jumpers must be installed to select the mode of the multiplexer 8 channels of differential inputs or 16 channels of single ended inputs This pair of jumpers is located above and to the right of P1 Both jumpers must be installed one below the other in either the 16 CH SE or 8 CH BAL positions The Single Ended Mode requires two connections per channel A ground wire and a signal wire The differential Mode requires two signal connections the input to the A D is the difference in potential between the two signal wires rather than the amplitude of either or both of them In Differential modes pickup interference will usually
35. data using the EMPTY bit to indicate when data is available Software gain at Base 4 should be configured for whichever range you ll actually be using or the Gain x1 setting The software gain amplifier is a laser trimmed part and does not need separate calibration per setting For optimum results data should be heavily averaged to eliminate any noise from the computations 43 Manual 104 AlO16 16E mb LG N 1 2 4 Adjust the value in the digital calibration potentiometer for the A D until the voltage read by the A D is correct Probably the best way to quickly find the correct value is to initialize the potentiometer with half its maximum value use 80 hex then increment or decrement the value until the A D reads accurately Store the value from the digital calibration potentiometer into a spot in the EEPROM for use on the next and subsequent board initializations The correct spot in EEPROM varies with the A D range and single ended differential selection being calibrated We recommend you use the same locations as our provided Calibration program drivers and samples as shown in Table C 1 below For example if you are calibrating the Offset of the 0 10 Volts Single Ended setting of the board we recommend you write the calibration Potentiometer value into the 5 location of the EEPROM Write the value using the procedure outlined in the description of Base A in Chapter 6 Gain Adjust Apply a known voltage to the A D Input When
36. e Start channel Each subsequent conversion will increment the channel number until it has acquired the End Channel It will start over at the Start Channel The current channel can be read at Base A bits 0 3 Any time you write to Base 2 the current channel is set to the Start Channel Step 1 2 Set Gain Code This step allows you to configure a different gain code per channel allowing for different input ranges on each channel of the board To set the gain code Word write to Base 4 Refer to Table 3 3 in Chapter 3 for a quick range gain reference Also see Chapter 6 Step 1 3 Start Conversion Writing any value to Base O will start a conversion on the current channel When the conversion is completed the data will be moved into the A D Data FIFO Step 1 4 Wait for FIFO not empty By checking the EMPTY bit in Base 8 determine when the FIFO has received the A D data While you are waiting your program can perform other operations such as DAC outputs without disturbing the A D Step 1 5 Read Data Read a 16 bit Word value from Base 0 to retrieve the results of the conversion from the A D Data FIFO Once you have the data you can store it on disk display on screen or whatever else your system requires Step 1 6 Until Done Repeat from 1 3 until you don t need any more data If start end channels and or gains need to be changed repeat steps 1 1 and 1 2 2 Burst Step 2 1 Set Channel Burst mode only takes data from one channel Wr
37. e factory it already has a valid set of calibration constants preloaded into the EEPROM for your immediate use The various calibration steps are all wrapped up in a calibration program for your use This program runs in DOS and compatible environments only and is written in Borland C C 3 1 with source code provided You will need a DVM and a calibrated voltage source to run the program The following steps are only necessary if you are writing your own calibration program e g for a new operating system If you are unable to run the provided calibration program it is recommended you examine its source code for details on performing the calibration in your own code The rest of the chapter is broken down into several sections First is an overview a kind of executive summary describing the two major steps involved in calibrating the board Following this is a breakdown of the 5 calibration steps for the DAC This breakdown is an engineering summary providing enough detail that someone very familiar with the board could proceed Last an in depth step by step walkthrough is provided Steps are numbered consistently between the overview breakdown and step by step sections of this section so you can easily flip between them to build an understanding of the process Overview Calibrating without using the provided calibration program Two parts exist to the calibration process and understanding these two parts is key to the entire pro
38. eeeceeeeeeeeeseeeaeceeeeeeeesesseaes 12 ADO COMIGUIAUON ae AAA sal sahs 13 Table 3 3 Gain Range Selection sr sa ss ka aaa EEE erev 13 Range Mode Selection uri 308282822808 13 Loading Calibration Constant sss eee 14 Chapter 4 Analog Digital Converter Operation sese 15 Overview A D Operational Modes eee 15 eU Ta ea naar ar SLED SETS RANE SES e NESAS EL SENSE LESS ER eee 15 POURS a ENDEN AAA A AA AE AA REESE ESS TREERE E 15 TINA SCAM SA AS TAG 15 Delayed Timed Scan Stall ini ii iia 15 EXTeENal SBan Stance oie ala neue A A A A A EA 15 Breakdown A D Operational Modes sese 16 Step By Step A D Operational Modes esse 17 READ DATA RA o Oi 19 Chapter 5 Digital Input Output u uue e aa aa 20 C hapler 6xPr gramming 2 2 2222 a aah ete ere 21 Table 6 1 Register Definition Map cocoa dncoco conca dacicn as 21 DAG data loading Write ee re ee iii caos 24 Chapter 7 Connector Pin Assignments een 32 Connector P1 26 pin IDC header male Analog Inputs MUX DAC Outputs 32 Connector P2 40 pin IDC Header Male sse 33 Connector P3 External Power 8 pin Male IDC Header sss sse 33 Appendix A Technical SpecificatiONS oooonnnnncnncccccnnccononnnnnnnnnnonononnnnnnnnnnnnonnnnnnannnnnnnos 34 Appendix B 82C54 Counter Timer Operation sss eee eee eee 36 Appendix E Cal DOM A 40 Table C 1 Factory EEPROM Calibration Locations sss eee eee eee eee
39. ency A D ScanStart Max Divisor Freg Generator Max Divisor D A Analog Outputs Number of Channels Resolution Ranges Safety Feature Accuracy Nonlinearity Update Rate Settling time Output current 250KHz in Burst mode single channel 250KHz in Scan mode 1 to 16 channels 2048 16 bit wide samples Requires two 8 bit reads or a 16 bit word read FIFO upgrades of 4K 8K 16K 32K samples available Automatic Calibration Offset and Gain Calibration Values stored in EEPROM individually for each range Software Programmable Gain Channel by Channel during Scan Unipolar Bipolar Single Ended Differential by jumper 0 5V 1V 2V 2 5V 5V 10V 0 1V 0 2V 0 5V 0 10V 16 single ended or 8 differential 16 bit successive approximation 1 Megohm 40V 75 84 dB depending on instrumentation amplifier gain 4 LSB typical Software Command Burst Timed Scan Start Delayed Timed Scan Start External Scan Start 2 samples channel 8 samples channel 16 samples channel software selectable 82C54 10MHz 32 bit 16 bit Two 12 bit 0 5V 0 10V via jumper selection Automatically set to zero on power up Automatic Gain Calibration Gain Values stored in EEPROM individually for each range and channel 0 2 LSB typical 10us 5KHz 8us 5mA source 34 Manual 104 AlO16 16E Digital I O Number of I O Programmable as Inputs Logic low Logic high current Outputs Logic low Logic high curre
40. er The input of counter 1 is fixed at 10MHz Counter 2 s output is at P2 Pin 40 Enable Counters 1 and 2 s gates via software at Base 1E OPERATIONAL MODES The 8254 modes of operation are described in the following paragraphs to familiarize you with the versatility and power of this device For those interested in more detailed information a full description of the 8254 programmable interval timer can be found in the Intel or equivalent manufacturers data sheets The following conventions apply for use in describing operation of the 8254 Clock A positive pulse into the counter s clock input Trigger A rising edge input to the counter s gate input Counter Loading Programming of a binary count into the counter Mode 0 Pulse on Terminal Count After the counter is loaded the output is set low and will remain low until the counter decrements to zero The output then goes high and remains high until a new count is loaded into the counter A trigger enables the counter to start decrementing Mode 1 Retriggerable One Shot The output goes low on the clock pulse following a trigger to begin the one shot pulse and goes high when the counter reaches zero Additional triggers result in reloading the count and starting the cycle over If a trigger occurs before the counter decrements to zero a new count is loaded Thus this forms a re triggerable one shot In mode 1 a low output pulse is provided with a period equal to the counter count down
41. h a Write of 0x00 to Base 3 Usually you ll be using the FIFO Half full IRQ or polling its status bit to time when to take data out of the FIFO ensuring it never reaches full See Base Address 8 for more information Base Address 4 Base Address 5 Software Programmable Gain Select 0 F Word Write Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Ch7 and 15 Ch6 and 14 Ch5 and 13 Ch4 and 12 Ch3 and 11 Ch2 and 10 Ch1 and 9 ChO and 8 Gain Code Gain Code Gain Code Gain Code Gain Code Gain Code Gain Code Gain Code The full scale range of the board depends on the settings of the Bipolar Unipolar and GNH GNL jumpers as described in Chapter 3 A gain code of 0 provides an amplifier gain of x1 1 provides a gain of x2 2 provides a gain of x5 while 3 provides a gain of x10 To quickly set all channels to the same gain multiply the gain code by 5555 hex then word write the result to Base 4 Please refer to Table 3 3 in Chapter 3 of this manual for a detailed breakdown of the effect of these bits Each time the A D changes to a new channel the A D gain will change according to the gain code configured here Base Address 8 Jumper Configuration Status Read Only Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EMPTY DFF DFH DASV DB5V GNH BIPOLAR SE Bit0 0 lt B
42. he known output voltage store it in the EEPROM for later use Doing so allows you to re write the value into the calibration potentiometer on the next board initialization without resorting to storing the values in a reference database or calibration configuration files on a hard disk or floppies etc The location into which you store the value varies based on the DAC number you re calibrating and the range you have selected on the board via jumpers Consult Table C 1 for a list of the locations the provided Calibration software samples and drivers use Repeat these steps for the other DAC Doing so means switching pins that you re reading on the DVM changing the channel select bits in the writes to Base 9 and changing the location you re writing the correct value into as described in the above steps When you ve finished these steps the DACs are calibrated The next time the board is reset only Step 2 needs to be performed In brief this involves reading the value out of the correct EEPROM location and writing it to the calibration potentiometer The details of Step 2 are described near the end of this appendix below 42 Manual 104 AlO16 16E Breakdown Calibrating the A D A D Calibration while fundamentally different than the DAC calibration process described above is also very similar In the A D calibration you are determining the amount of calibration error adjusting the digital potentiometers until the error is eliminated and st
43. ich will result in a non or poorly calibrated situation The calibration values are stored in an on board EEPROM allowing simple re use of calibration data from one boot to the next 5 Manual 104 AlO16 16E VREF 16 S E 8 DIFF L CHO HI SIGNAL COND 16 BIT A D CONVERTER CHO LOc INCL CALADJ 500 KSamples Second EEPROM CAL DATA eee AID DATA FIFO 8 DIFF L ANALOG MUX INPUTS CONTAINED STATUS IN CPLD REGISTER CH15 o INTERRUPT CONTROL MUX INCREMENT REGISTERS amp CONTROL LOGIC CONTROL a x 4 x P 16 BITS A K 4 v Moon E HE 16 BITS EAE K INTERNAL DATA BUS gt C Da zu EDNA OUTPUT BUFFERS Y d TRIGGER 10 MHz 10MHz SELECT B SCAN START LOGIC y A D TRIGGER o gt ADDRESS Sr DECODE K y K SIGNAL COND y i 7 amp DAC A o INCL CALADJ vv yy SELECT DUAL 12 ds E __ SIGNAL COND BACHE INCL CAL ADJ GTR STR ETR CTRO CTR2 OUT OUT Figure 1 1 Block Diagram 6 Manual 104 AlO16 16E Chapter 2 Installation ENSURE YOU HAVE APPROPRIATE POWER IN YOUR PC 104 STACK TO OPERATE THIS DATA ACQUISITION BOARD It requires 5V and 12V to operate properly unless you purchased the board with a DC DC converter The paper label on the board will indicate DC if a DC DC converter is instal
44. igh byte of the count b the low byte of the count or c the low byte followed by the high byte This last is of the most general use and is selected for each counter by setting the RW1 and RWO bits to ones Of course subsequent read load operations must be performed in pairs in this sequence or the sequencing flip flop in the 8254 chip will get out of step The readback command byte format is B7 B6 B5 B4 B3 B2 B1 BO 1 1 CNT STA C2 C1 CO 0 CNT When 0 latches the counters selected by bits CO C2 STA When 0 returns the status byte of counters selected by CO C2 CO C1 C2 When high select a particular counter for readback CO selects Counter 0 C1 selects Counter 1 and C2 selects Counter 2 You can perform two types of operations with the readback command When CNT 0 the counters selected by CO through C2 are latched simultaneously When STA 0 the counter status byte is read when the counter I O location is accessed The counter status byte provides information about the current output state of the selected counter and its configuration The status byte returned if STA 0 is B7 B6 B5 B4 B3 B2 B1 BO OUT NC RW1 RW2 M2 M1 MO BCD OUT Current state of counter output pin NC Null count This indicates when the last count loaded into the counter register has actually been loaded into the counter itself The exact time of load depends on the configuration selected
45. inish acquiring all the channels specified in Base 2 l e if you are acquiring 8 channels of data you need at least 8 2 5 uSec 20 20 microseconds between Counter 1 and 2 timeouts Please refer to Appendix B for information on programming the 8254 Counter Timer chip Data acquisition is continuous When the FIFO is filled data storage pauses It resumes when data is read from the FIFO thereby changing its FULL state It is expected that when operating in this mode the application program will be reading data from the FIFO as it is being written by the A D preventing the FIFO from filling during data acquisition This is normally accomplished by reading data equal to half of the FIFO capacity whenever the FIFO half full flag is used to generate an interrupt See READ DATA FAST in Chapter 4 for more information on various ways to get data from the board NOTE Program Counters 1 and 2 before using Base 1A and Base 1E to start Data Acquisition Base Address 19 Reset Digital I O to Input Mode Write Any write to this address results in both Digital I O Blocks being put into the input read mode Refer to Base 10 and Base 11 for more information Base Address 1A Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit O x x X Enable X X X X Disable Bit 4 of Base 1A is used in conjunction with bit 6 of Base 1E to enable modes Timed Scan Start Delayed Timed Scan Start and External Scan
46. ite the channel you want to take data from to bottom nybble of Base 2 Step 2 2 Set Gain All of the data taken will be at the same gain code range Specify the range you want by Word writing to Base 4 Refer to Table 3 3 in Chapter 3 for a quick range gain reference Step 2 3 Start Burst Write 0x01 to Base 3 to start Burst Mode As soon as the byte is written data will be taken at the 250KHz rate As each conversion completes the data will be moved into the A D Data FIFO If any data is in the FIFO the EMPTY bit bit 7 0 for NOT EMPTY will so indicate and if the FIFO reaches half full the DFH bit bit 5 1 for HALF FULL or MORE will so indicate when reading from Base 8 Step 2 4 READ DATA FAST Various methods for reading the data are explained in the section READ DATA FAST The maximum read rate same as conversion rate every conversion requires a read 250KHz is fast If you fail to take the data out of the FIFO fast enough it will fill If the FIFO reaches full the burst will pause until some data has been removed from the FIFO to make room for more Step 2 5 Disable Burst Whenever you have enough data for your needs Write 0x00 to Base 3 to stop the A D conversions 3 Timed Scan Start Step 3 1 Jumper Pins 38 and 40 See Chapter 3 Power Off Step 3 2 Set Channel Please see Software mode Step 1 1 for information Step 3 3 Set Gain Code Please see Software mode Step 1 2 for information Step 3 4 Configure Counters
47. le by polling the EMPTY bit When the FIFO is not empty you read one sample This method is simple to program but not very resource efficient reading the status register and the FIFO for every sample can result in a very busy computer Despite the drawbacks this method is often the best when data rates are very slow or the only goal is to quickly test operation of the card The fastest method is to INSW 1024 samples from Base 0 every time the DFH bit indicates the FIFO is half full A slightly slower method is to enable the DFH IRQ This will generate an IRQ each time DFH is true and have an ISR respond to the IRQ by using INSW to read 1024 samples To enable the DFH IRQ write the value 0x10 to Base C Write value 0x00 to Base C to disable DFH IRQ operation NOTE Since this is an 8 bit PC 104 bus board and the A D Data is 16 bits wide two sequential reads are necessary to retrieve the 16 bits of the converted Data However by assuming the data can be read as a 16 bit value and issuing a word read instead of two byte reads the bus controller on the computer will optimize the operation and reduce the overhead associated with reading the data 19 Manual 104 AlO16 16E Chapter 5 Digital Input Output The use of the Digital Input Output function is completely controlled by application software There are two independent Digital I O ports Each port consists of 8 bits The external connections are via connector P2 and are listed in Chapte
48. led Boards with the DC option only require 5V at about 250mA A printed Quick Start Guide QSG is packed with the board for your convenience If you ve already performed the steps from the QSG you may find this chapter to be redundant and may skip forward to begin developing your application The software provided with this PC 104 Board is on CD and must be installed onto your hard disk prior to use To do this perform the following steps as appropriate for your operating system Substitute the appropriate drive letter for your CD ROM where you see d in the examples below CD Installation The following instructions assume the CD ROM drive is drive D Please substitute the appropriate drive letter for your system as necessary DOS 1 Place the CD into your CD ROM drive 2 Type Je to change the active drive to the CD ROM drive 3 Type J s allen to run the install program 4 Follow the on screen prompts to install the software for this board WINDOWS 1 Place the CD into your CD ROM drive 2 The system should automatically run the install program If the install program does not run promptly click START RUN and type JJUNSTAUJU click OK or press Ex 3 Follow the on screen prompts to install the software for this board LINUX 1 Please refer to linux htm on the CD ROM for information on installing under linux 7 Manual 104 AlO16 16E Installing the Hardware Before installing the board carefully read Cha
49. locked please cut these two pins as shown from the solder side of this board It is not necessary to block the holes on the component side of the board O Pin 1 Figure 2 1 PC 104 Key Information 8 Manual 104 AlO16 16E Chapter 3 Option Selection Jumpers are available on the board to setup the following selections 12V Source Select Base address IRQ level DAC output voltage ranges A D input mode single ended or differential Input Voltage Range A D start operational mode Please refer to the Setup Program on the Software Master CD for details on selecting the appropriate options for your application EXTERNAL SCAN TRIGGER 38 GND 37 EXTERNAL SCAN START MODE DELAYED EXTERNAL USES EXT SIGNAL TO START EACH SCAN TRIGGER 36 GND 35 N DELAYED TIMED SCAN START MODE WAITS FOR EXT SIGNAL THEN USES 8254 CTR TIMED SCAN START MODE USES 8254 CTR TO TIME A D SCANS 12V SOURCE SELECT LOOR OO BBBBB DODDI OOOOO Taa UNIPOLAR BEBBE ILLIA POLOO WAON Figure 3 1 Option Selection Map 9 Manual 104 AlO16 16E Address Selection The board s Base Address is set by jumpers labeled BOARD ADDR The jumpers are marked A5 through A9 and A5 is the least significant bit of the address The base addresses can be selected anywhere within the I O address range 000 3E0 provided that they do not overlap with other functions The
50. mode Write 0x10 to Base 1A 4 7 Data started by External Trigger See Figure 3 1 for connection 4 8 READ DATA FAST 4 9 Stop Data acquisition Write 0x00 to Base 1A and Write 0x00 to Base 1E External Scan Start 5 1 Connect External Scan Start signal to pins 37 and 38 See Chapter 3 Power OFF 5 2 Set Channel Scan Limits Write to Base 2 5 3 Set Gain Code Word Write to Base 4 5 4 Configure Oversampling defaults to x1 Write to Base 1F 5 5 Set Enable code Write 0x10 to 1A and Write 0x40 to Base 1E 5 6 External Start Signal should be started 5 7 READ DATA FAST 5 8 Set disable code Write 0x00 to Base 1A and Write 0x00 to Base 1E 1 Software start conversion mode is the most efficient way to achieve different gains channel In other modes timing the gain changes involves obscure operations related to Base A Read Several methods exist to read the data quickly from the board Consult the section READ DATA FAST 16 Manual 104 AlO16 16E Step By Step A D Operational Modes Now let s describe these modes in detail All Base xx offsets are in hexadecimal Please refer to Chapter 6 Programming for more information on these Base xx registers 1 Software Step 1 1 Set Channel Scan Limits Base 2 contains the Start and End Channel Scan Limit register The top nybble is the End Channel and the bottom nybble is the Start Channel In this mode the A D will take its first conversion on th
51. nt Logic low Logic high Update rate Pull Up Resistor General Power required Operating Temperature Storage Temperature Humidity Size and Bus Type I O Connectors Cable Accessories Screw Terminal Boards 16 Inputs or Outputs in groups of 8 0 0V min 0 8V max 2 0V min 5 0V max 1HA max 0 0V min 0 55V max 2 4V min 5 0V max 24mA max sink 24mA max source up to 1 MHz 10K each I O line 5VDC 100mA typical 12VDC 50mA typical each With DC DC Converter 5V 250mA typical no 12VDC is used 0 to 70 degrees C 50 to 120 degrees C 5 to 90 RH non condensing PC 104 compliant 8 Bit PC 104 with 16 Bit pass through connectors and extended IRQ s 26 and 40 Pin right angle header with 0 1 spacing Cable Part Numbers C104 26F X and C104 40F X X length in inches Part Numbers STB 26 and STB 40 also 104 STA 16E 35 Manual 104 AlO16 16E Appendix B 82C54 Counter Timer Operation The board contains one type 8254 programmable counter timer The 8254 is a flexible but powerful device that consists of three independent 16 bit presettable down counters Each counter can be programmed to any count between 2 and 65 535 in binary format depending on the mode chosen On the board these three counters are designated Counter 0 Counter 1 and Counter 2 Counter 0 s input clock is fixed at 10MHz The gate to Counter 0 is always enabled Counters 1 and 2 are concatenated by the board to form a single 32 bit count
52. ock period when the terminal count is reached The counter is retriggerable The output will not go low until the full count after the rising edge of the trigger 36 Manual 104 AlO16 16E PROGRAMMING On this board the 8254 counters occupy the following addresses hex Base Address 14 Read Write Counter 0 Base Address 15 Read Write Counter 1 Base Address 16 Read Write Counter 2 Base Address 17 Write to Counter Control register The counters are programmed by writing a control byte into a counter control register The control byte specifies the counter to be programmed the counter mode the type of read write operation and the modulus The control byte format is as follows B7 B6 B5 B4 B3 B2 B1 BO SC1 SCO RW1 RWO M2 M1 MO BCD SC0 SC These bits select the counter that the control byte is destined for SC1 SCO Function 0 0 Program Counter 0 0 1 Program Counter 1 1 0 Program Counter 2 1 1 Read Write Cmd See section on READING AND LOADING THE COUNTERS RWO RW1 These bits select the read write mode of the selected counter RW1 RWO Counter Read Write Function 0 0 Counter Latch Command 0 1 Read Write LS Byte 1 0 Read Write MS Byte 1 1 Read Write LS Byte then MS Byte MO M2 These bits set the operational mode of the selected counter MODE M2 M1 MO 0 0 0 0 1 0 0 1 2 X 1 0 3 x 1 1 4 1 0 0 5 1 0 1 BCD Set
53. of data Always set D1 and DO to 1 17 Oxxxxx00 00 Update DAC Always write 00 as the 47 byte 18 Oxxxxx10 02 End Always write 02 as the 18 byte As you can see from the table the only writes that can vary from one output to the next are the DAC channel number in bytes 2 and 3 and the data in bytes 5 through 16 The only valid values for these bytes are 03 or 83 Byte 1 must always be 81 Byte 4 must always be 03 Byte 17 must always be 00 and Byte 18 must always be 02 For ease of reference the bits which you can change are typeset in bold The behavior of the DAC is undefined if these guidelines are not followed 24 Manual 104 AlO16 16E Base Address A EEPROM Data Write and Read bit 7 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit1 Bit O Write Data X X X X X X SClock Read Data X X X X X X X The Software Master CD contains sample programs demonstrating the use of the EEPROM in a variety of languages including a driverlet which encapsulates the complexities of the process Using this driverlet is as simple as passing the address and data in the EEPROM you wish to write or the address from which to read to our functions It is highly recommended that you use the provided source code as a basis for your own programs The EEPROM is intended to hold calibration data for the A D Gain and Offset correction and the Gain Correction data for both DACs Calibration is only needed for GNL GNH
54. oring the adjustment for later use Unlike the DAC there are two digital potentiometers for the A D offset adjust and gain adjust The same two steps apply Step 1 Determine the calibration constants Step 2 Write the calibration constants into the calibration potentiometers First let s expand Step 1 into its component sub steps for the A D Step 1 Determine the Calibration Constants for the A D 1 1 XX A n A 1 2 3 1 1 4 gt m x NRK WN 1 2 4 Offset Adjust Apply a known low voltage to the A D input Acquire the voltage using the A D converter Adjust the value in the digital calibration potentiometer for the A D until the voltage read by the A D matches the input voltage Store the value from the digital calibration potentiometer into a spot in the EEPROM for use on the next and subsequent board initializations Gain Adjust Apply a known voltage to the A D Input Acquire the voltage using the A D converter Adjust the value in the digital calibration potentiometer for the A D until the voltage read by the A D matches the input voltage Store the value from the digital calibration potentiometer into a spot in the EEPROM for use on the next and subsequent board initializations Step 2 Write the Calibration Constants into the Calibration Potentiometers For details on step 2 please refer to the section Step 2 near the end of this appendix Note 1 The known voltage to use varies wi
55. ound 17 A D Ch 5 Input 18 Ground 19 A D Ch 6 Input 20 A D Ch 14 Input 19 A D Ch 6 Input 20 A D Ch 6 Input 21 Ground 22 A D Ch 15 Input 21 Ground 22 A D Ch 7 Input 23 A D Ch 7 Input 24 Ground 23 A D Ch 7 Input 24 Ground 25 DAC 0 Output 26 DAC 1 Output 25 DAC 0 Output 26 DAC 1 Output 32 Manual 104 AlO16 16E IDC 40 Pin Header Male aaa aaa 90 ld E Bei E a E E al Wl E RANA EA al EEN i Connector P2 40 pin IDC Header Male Digital I O 8254 Counter and A D Trigger Input The connections for the Digital Input Output Signals are provided on the odd numbered pins from 1 to 31 The Digital I O are 1 DIO 0 2 Ground configured in blocks of 8 Pin Function Pin Function E 20 i lale The Delayed external trigger input pin 36 may be used to provide 5 DIO 2 6 Ground an external trigger source for the Delayed Time Scan Start If this option is used the board must be configured 7 DIO 3 8 Ground appropriately as described in Chapter 3 9 DIO 4 10 Ground A i The other connections involve the counter 11 DIO 5 12 Ground Counters 1 and 2 are concatenated internal to the board For normal counter driven A D timing operation please connect Ctr2 Out pin 40 to pin 38 Scan Start 13 DIO 6 14 Ground 15 DIO 7 16 Ground See Chapter 4 and 6 for more information on A D Timing Modes ae le E Ground See Appendix B for details on programming the counter circuit
56. peration are available Software Burst Timed Scan Start Delayed Timed Scan Start External Scan Start 1 Software In this mode conversions are started by the software command A write to base O takes data from one channel entry beginning at the starting address from base 2 If more than one channel is selected in base 2 ie start and end address are different each write to base 0 increments to the next sequential channel This mode is used primarily for test and development 2 Burst Takes data at 250KHz from the starting channel in base 2 Started and stopped by software command 3 Timed Scan Start Takes one scan of data each time the output of counter2 goes low Each scan consists of data beginning at the starting channel from base 2 and finishing at the ending channel from base 2 Furthermore the value from base 1F oversample value determines how many times data is taken from each channel within the scan Oversampling and channel switching within the scan happen at 250KHz This mode is setup and started by software 4 Delayed Timed Scan Start Same as Timed Scan Start except data is taken only after a single falling edge of the external delayed input pin refer to Figure 3 1 for pin configuration 5 External Scan Start Same as Timed Scan Start except that each scan is started by a falling edge of the external scan input pin refer to Figure 3 1 for pin configuration A scan must be complete before
57. provides a clear introduction to several of the concepts used in calibrating the A D The process is designed to evaluate the differences between what you ve asked the DAC to output and what it really produces This difference is the amount the board is out of calibration By adjusting digital potentiometers in the DAC circuit you reduce this calibration error by successive approximation until it reaches zero When it is zero and the board is calibrated you store the amount of adjustment for later use First let s expand Step 1 mentioned above into its component sub steps for the DAC Step 1 Determine the Calibration Constants for the DAC 1 1 Output a value corresponding to a known voltage on aDAC 1 2 Measure the output value of the DAC with a DVM 1 3 Adjust the value in the digital calibration potentiometer for that DAC until the voltage read by the DVM matches the known value being output 1 4 Store the value from the digital calibration potentiometer into a spot in the EEPROM for use on the next and subsequent board initializations 1 5 Repeat steps for the other DAC Step 2 Write the Calibration Constants into the Calibration Potentiometers For details on Step 2 please refer to section Step 2 near the end of this appendix 1 The value corresponding to a known voltage to output depends on the range of the DAC as selected by jumpers on the board Software can determine the current jumper configured range using the status register
58. pter 3 and Chapter 4 of this manual and configure the board according to your requirements The SETUP Program can be used to assist in configuring jumpers on the board Be especially careful with Address Selection If the addresses of two installed functions overlap you will experience unpredictable computer behavior To help avoid this problem refer to the FINDBASE EXE program installed from the CD The setup program does not set the options on the board these must be set by jumpers To Install the Board 1 Install jumpers for selected options and base address according to your application requirements as mentioned above 2 Remove power from the PC 104 stack Assemble standoff hardware for stacking and securing the boards 4 Carefully plug the board onto the PC 104 connector on the CPU or onto the stack ensuring proper alignment of the pins before completely seating the connectors together 5 Install I O cables onto the board s I O connectors and proceed to secure the stack together or repeat steps 3 5 until all boards are installed using the selected mounting hardware 6 Check that all connections in your PC 104 stack are correct and secure then power up the system 7 Run one of the provided sample programs appropriate for your operating system that was installed from the CD to test and validate your installation ga If you are installing this board into a PC 104 Pin 0 g stack that has the holes for Pin C19 and BC a B10 b
59. r 7 Port 0 is located at Base Address 10 and reads writes pins DIOO through DIO7 Port 1 is located at Base Address 11 and reads writes pins DIO8 through DIO15 Both ports default to input read mode Each remains in that mode until written to When written to that port will switch to and remain in output write mode Both ports may be reset to the input mode by writing anything to Base Address 19 Please refer to the appropriate section of Chapter 6 for more information 20 Manual 104 AlO16 16E Chapter 6 Programming The following table shows the register definition map All offsets are in hexadecimal Note Word Read Writes are helpful and preferred for reading A D data writing A D gains Digital I O Offset Write Function Read Function 0 Start A D Conversion Read A D Data FIFO LSB 1 A D Data FIFO Reset Read A D Data FIFO MSB 2 A D Channel Scan Control 3 A D Burst Mode Control 4 A D Software Gain Select Ch 0 3 8 11 5 A D Software Gain Select Ch 4 7 12 15 6 7 Reset Software A D Gain to ONE 8 Jumper Configuration Status 9 DAC Outputs A EEPROM Data Write EEPROM Read B Calibration Data Write C Enable Disable IRQ D E F 10 Digital Outputs O 7 Digital Inputs 0 7 11 Digital Outputs 8 15 Digital Inputs 8 15 12 13 14 Program Counter O Read Counter 0 15 Program Counter 1 Read Counter 1
60. ress for the scan and the E entries refer to the ending address for the scan The scan is performed on each channel between the starting and ending address inclusively Write same address in both nybbles to sample one channel When the board is operated in the Differential mode E S MA3 is ignored When the board is operated in the Single Ended mode E S MA3 is the most significant bit of the input address Notes The selection of Single ended or Differential inputs must be made by properly installing jumpers on the board Please refer to Chapter 3 or the Setup program for details Since the MUX addresses do not advance during the burst mode the ending address EMA3 EMAO is ignored and all conversions occur on the channel specified in SMA3 SMAO 22 Manual 104 AlO16 16E Base Address 3 A D Burst Mode Control Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 x x x x x x x Start Stop This register enables burst mode Write 0x01 to start 0x00 to stop Set desired channel using Base 2 Burst Mode operation acquires data on the start channel stored in Base 2 SMA3 SAMO at the maximum speed of the A D approximately 4 microseconds per conversion 250KHz This data is stored in the FIFO Conversions pause when the FIFO is full Conversions resume when a FIFO read command removes data from the FIFO Base 0 thereby removing the FIFO full state Alternatively operation can be stopped wit
61. s equates to F32 hex which we ll write to the DAC as described at Base 9 Its important that you are precise when calibrating so don t forget about that 0 25 count we threw away If we run the equation backwards to determine what voltage F32 counts equates to we don t get 9 5 volts Let s run the math Volts Counts MaxCounts MaxVolts so Volts F32 FFF 10 0 9499 10 9 499 Volts Not quite 9 5 volts 41 Manual 104 AlO16 16E 1 2 1 3 1 4 1 5 Measure the output value of the DAC with a DVM Now that we know precisely what output voltage to expect connect a DVM to the DAC output pin on P1 pin 25 or pin 26 for DAC 0 or DAC 1 respectively Use Pin 24 for ground The DVM should be set for DC voltage measurement Once connected the DVM should read 9 499 Volts but may not be exactly correct Remember if you re using a different known output value you should see a number near it not near 9 499 Adjust the value in the digital calibration potentiometer for the DAC you re calibrating until the reading on the DVM shows your known output value You adjust this potentiometers value using the process described in Base B in Chapter 6 Probably the best way to quickly find the correct value is to initialize the potentiometer with half its maximum value use 80hex then increment or decrement the value until the DVM reads accurately Once you ve determined the value that correctly adjusts the DAC output to match t
62. s to be out of calibration or approximately every 6 12 months depending on environmental and usage considerations Step 2 however needs to be performed every time the board is reset In Step 2 you merely perform a read from the EEPROM and write the value to the digital calibration potentiometers for each of the digital pots 2 1 2 2 Determine the location in the EEPROM for the calibration constants The register at Base 8 Chapter 6 indicates the currently jumper selected range for both the A D and the DAC Read this register Software should not assume the user has left the range setting where it was Read the correction constants from the EEPROM Correlate the jumper settings as read with the Table C 1 and read the EEPROM entries for the A D Offset A D Gain and the DAC 0 and DAC 1 corrections Base A in Chapter 6 describes the process of reading from the EEPROM 44 Manual 104 AlO16 16E 2 3 EEPROM Location Calibration Value Stored 0 unused 1 unused 2 Offset B 10V Differential 3 Offset B 10V Single ended 4 Offset B 0 10V Differential 5 Offset B 0 10V Single ended 6 Offset B 5V Differential 7 Offset B 5V Single ended 8 unused 9 unused A Scale M 10V Differential B Scale M 10V Single ended C Scale M 0 10V Differential D Scale M 0 10V Single ended E Scale M 5V Differential F Scale
63. t of data written Always set DO to 1 26 Oxxxxxx0 00 End Always write 00 as the 26 byte For ease of reference the bits which can change are typeset in bold Please note it is not possible to write to the EEPROM until an EEPROM WRITE ENABLE EWREN sequence has been written to Base A The EWREN sequence consists of the following bytes in order 81 01 01 81 81 01 01 01 01 00 Once the EWREN sequence has been written it is possible to write to the EEPROM as desired If you wish to subsequently disable writes to the EEPROM a disable sequence of bytes may be written to Base A as follows 81 01 01 01 01 01 01 01 01 00 26 Manual 104 AlO16 16E Reading from the EEPROM Base A Similarly reading a word takes 10 writes start bit read opcode 2 bits 1 0 and the address 6 bits MSB first followed by 16 reads to acquire the data from the eeprom followed by one write to terminate communication with the eeprom Therefore to read from address 4 the following reads and writes are performed Write Value Description 1 1xxxxxx1 81 Start Bit Always write 81 as the 1 byte 2 1xxxxxx1 81 Opcode Bit 1 Always write 81 as the 2 byte for reading 3 Oxxxxxx1 01 Opcode Bit 0 Always write 01 as the 3 byte for reading 4 Oxxxxxx1 01 MSB of address Bit 7 should be 1 or 0 based on the D5 bit of address in the EEPR
64. tage based on the jumper and software selected A D input range Refer to Chapter 3 for information on range selection and Base 4 for more information on software selectable gains Please note in bipolar ranges the value 0000 corresponds to maximum negative voltage For example if the board is configured for a 2V range FFFF is 2V 0000 is 2V and 8000 is OV Consult the sample code on the provided CD for examples of algorithms to convert the hexadecimal return value to voltage for any arbitrary range Base Address 1 A D Data FIFO Reset Writing any value to this address resets the FIFO This will empty the FIFO of any data that remains It is a good idea to reset the data FIFO before you start any data acquisition process to ensure you re in good sync with the data that will be acquired Make sure the A D isn t currently acquiring data before issuing this command Chapter 4 and the descriptions of Base 3 Base 1C Base 1D Base 1E have more information on various ways acquisition could be happening Base Address 2 A D Channel Scan Control write only Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EMA3 EMA2 EMA1 EMAO SMA3 SMA2 SMA1 SMAO This register controls the channel scan limits for the A D input multiplexer Specify a channel number from 0 to 15 0 F in each nybble for the start and end limit of the auto incrementing mux channel number The S entries refer to the starting add
65. th the jumper selected A D input range For best results apply a voltage within 5 of the minimum scale most negative voltage for your selected range Note 2 The correct spot in EEPROM varies with the A D range and single ended differential selection being calibrated We recommend you use the same locations as our provided Calibration program drivers and samples as shown in Table C 1 following Note 3 The known voltage to use varies with the jumper selected A D input range For best results apply a voltage within 5 of the full scale voltage for your selected range Step By Step Calibrating the A D Step 1 Determine the Calibration Constants for the A D 1 1 1 1 1 Offset Adjust Apply a known low voltage to the A D input For best results all channels should have this voltage but any single channel would also work The voltage should be 5 above the minimum scale most negative voltage for your selected range For example in the 10V range this would be 9V and in the 0 10V range this would be 0 5V Acquire the voltage using the A D converter The simplest way is using the Software Mode Software mode is described in Chapter 4 In essence it consists of five steps Set Channel Set Gain Start Conversion Wait for End of Conversion Read Data For calibration purposes the Channel should be whichever channel has the known voltage applied The Channel Scan Limits register at Base 2 should contain only that one channel Read the
66. time Mode 2 Rate Generator This mode provides a divide by N capability where N is the count loaded into the counter When triggered the counter output goes low for one clock period after N counts reloads the initial count and the cycle starts over This mode is periodic the same sequence is repeated indefinitely until the gate input is brought low Mode 3 Square Wave Generator This mode operates periodically like mode 2 The output is high for half of the count and low for the other half If the count is even then the output is a symmetrical square wave If the count is odd then the output is high for N 1 2 counts and low for N 1 2 counts Periodic triggering or frequency synthesis are two possible applications for this mode Note that in this mode to achieve the square wave the counter decrements by two for the total loaded count then reloads and decrements by two for the second part ofthe wave form Mode 4 Software Triggered Strobe This mode sets the output high and when the count is loaded the counter begins to count down When the counter reaches zero the output will go low for one input period The counter must be reloaded to repeat the cycle A low gate input will inhibit the counter This mode can be used to provide a delayed software trigger for initiating A D conversions Mode 5 Hardware Triggered Strobe In this mode the counter will start counting after the rising edge of the trigger input and will go low for one cl
67. tive during the warranty period In no case is ACCES liable for consequential or special damage arriving from use or misuse of our product The customer is responsible for all charges caused by modifications or additions to ACCES equipment not approved in writing by ACCES or if in ACCES opinion the equipment has been subjected to abnormal use Abnormal use for purposes of this warranty is defined as any use to which the equipment is exposed other than that use specified or intended as evidenced by purchase or sales representation Other than the above no other warranty expressed or implied shall apply to any and all such equipment furnished or sold by ACCES 3 Manual 104 AlO16 16E Table of Contents Chapter Is IMMOCUCION nennen 5 Analog AU ac rare 5 A O 5 Digital O Atl ceeded ad NE 5 Counter Time rar rare er le a rer URL eee ER I ONE 5 CAMION AA aeg 5 Figure 1 1 Block Diagram sss sss 6 Chapter 2 Installation 222 od O ARA A AA tote A A re 7 BBnstallation ass id a a 7 Installing the Marware tdci idas 8 To lnstallthe Board IEA RAE AAA AAA 8 Chapter 3 Option Selection it A RA ARA AAA 9 Figure 3 1 Option Selection Map sese eee 9 Address ele A DE DE Bieta aap pees 10 Table 3 1 Address Selection and Hex Conversions sese 10 Table 3 2 Hex Ranges for Standard Computers sss eee eee 11 IRO Configuration 0 SAA AAA AA AAA AA AAA 12 DAG CONQUE MON ducati 12 Frequency Generator Configuration ccccccccccceeeeeeeeeeeeeeeeeae
68. ut of 10MHz n where 1 lt n lt 65536 The output of Counter 0 is seen on connector P2 pin 33 Also note that if you are using non counter timed A D modes Counter 2 becomes available for frequency generation A frequency of 10MHz n where 1 lt n lt 2 can be generated The output of Counter 2 is seen on connector P2 pin 40 Consult Chapter 4 Chapter 6 and Appendix B for more information on the A D programming and the counter itself 12 Manual 104 AlO16 16E A D Configuration In order to use the A D properly the following operations must be completed 1 The range of the A D must be set by selecting jumpers on the board 2 The mode single ended or differential of the A D input must be selected by jumpers on the board 3 The appropriate calibration constants should be loaded into the digital calibration potentiometers used with the A D Jumpers Prog Gain 0 Prog Gain Prog Gain 2 Prog Gain 3 1 GNH Unipolar O 10V 0 5V 0 2V 0 1V Bipolar 5V 2 5V 1V 0 5 GNL Unipolar invalid invalid invalid invalid Bipolar 10V SV 2V 1V Table 3 3 Gain Range Selection Range Mode Selection Carefully plan which range to select on the board by examining Table 3 3 Only the ranges shown in a single row are available simultaneously via software control For example if you want to use both 5V and 2V inputs you must select GNL Bipolar range if you re using only 5V inputs you

MODEL 104-AIO16-16E USER MANUAL

Contents

Download Pdf Manuals

Related Search

Related Contents