Acqutek - PA-MA12(-H) (details)
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Similar / Related Products PI-IO48A - PA-CP12 - PA-ST12(-H) - PA-MA12(-H) - PA-MD12(16) - PA-AD12(-H) - PA-DA12(16)
XC-IO96 - XC-AD12 - XC-DA12
XI-PI08 - XI-IM04 - XO-RR08 - XO-SRD4/XO-SRA4 - ST-XD02 - ST-DM37 - IC-XCXD

PA-MA12(-H) Brief Description
DMA transfer A/D D/A Card

Description - Model No - Expansion - Block Diagram - A/D - D/A - I/O - Register - Programming - Specifications


    DMA transfer multi I/O Card (A/D , D/A and digital I/O).
    12 bits, 50 KHz DMA data transfer A/D.
    16 single-ended or 8 differential analog inputs (A/D).
    8254 timer provides background conversion.
    One 12-bits analog output (D/A).
    24 programmable digital inputs/outputs.


    The PA-MA12 is a DMA data transfer A/D, D/A, and digital I/O card. This high speed converter performs A/D conversions with DMA transfer. This ensures fast background conversion speeds regardless of the specific computer in use.

    This card provides 16 single-ended or 8 differential 12 bit analog to digital conversions (A/D). The conversion time for PA-MA12 is 20 us; for PA-MA12-H is 10 us. This card uses DMA data transfer, pipe-line technology for switching channels, S/H, conversion and latch conversion results. So, no matter what kind of CPU you use, the conversion speed for PA-MA12 will be 50KHz, and for the PA-MA12-H it will be 100KHz.


    A/DResolution12 Bit12 Bit
    Channels8 diff or 16 s-e8 diff or 16 s-e
    Conversion Time20 us (50KHz)10 us (100KHz)
    Accuracy11 Bit1 Bit
    D/AResolution12 Bit12 Bit
    Conversion time10 us10 us
    Accuracy11 Bit11 Bit
    Digital I/O24 channels total (8255) Input /Output programmable


    All ports can be programmed as inputs or outputs. Both have optional expansion modules (daughter cards) that extend the I/O for interfacing operations. These modules are called XDI expansion boards and include options like reed-relays or photo-coupled input modules.

    Model No. Function
    XI-PI08 3-32V photo-coupled input expansion
    XI-IM04-32 12-32V AC/DC input expansion
    XI-IM04-140 90-140V AC/DC input expansion
    XI-IM04-280 180-280V AC/DC input expansion
    XO-RR08 10VA reed relay output expansion
    XO-SRD4 3A 5-60V DC S.S.R. output expansion
    XO-SRA4 3A 24-280V AC S.S.R. output expansion
    ST-XD02 2 XDI screw terminal board
    IC-XCXD Chassis for XCI/XDexpansion cards



    Analog Input (A/D)

    The PA-MA12(-H) provides 16 single-ended or 8 differential channels, 12 bit, 20/10us analog to digital conversion.

    ADC block diagram

    The signal connector - The connector for the analog input signals is a 37 pin D-type male connector. A screw terminal board and a chassis for the screw terminal board are available as optional products.

    A/D channel selection - The PA-MA12(-H) can be configured for 8 differential inputs or 16 single ended inputs. The configuration is set by an on-board jumper. The channel can be selected by writing the channel limit to channel selection port (base+2).

    Sample and hold - The PA-MA12(-H) uses a sample and hold circuit that depends on the end of conversion (EOC) signal from the ADC. Thus, the input signal will be held during the conversion.

    A/D conversion control - The A/D conversion can be triggered in three ways. They are selected by writing the command to the A/D command port (base+3).

      Trigger method 1 : S/W trigger conversion
      The first type of conversion is software triggered conversion. This method is very easy to implement because the software is directly controlling the A/D conversions. The conversion will be started by writting any data to the S/W trigger port (base+0).
      Trigger method 2 : External clock conversion
      The external clock conversion consists of using an external clock or pulse, longer than 200 nanoseconds, to trigger the A/D conversion. The signal comes in from a jumper connection on the PA-MA12(-H). This gives the user great flexability in providing a trigger signal that enables one to synchronize the A/D with other devices.
      Trigger method 3 : 8254 timer conversion
      The 8254 timer conversion is similar to external triggering except the 8254 timer conversion uses the 8254 timer controller to generate accurate time pulses to trigger and start the conversions. An option that goes with this is to gate the 8254 timer trigger signals with the external signal (from a jumper). In other words, the timer signal and the external signal would be ANDed to give one external control over A/D conversions with the 8254 timer.

    A/D conversion - When the conversion takes place, the EOC (End Of Conversion) line goes high, and the input voltage will be held by the sample and hold circuit. Once the conversion is initiated (EOC goes high), no other start conversion command will be accepted until the completion of the conversion. Upon completion of the conversion, the EOC line goes low, the least significant byte (LSB) and the most significant byte (MSB) of the digital value for the voltage will be stored in a temperary buffer, and the data will not be changed until the completion of next conversion. The data can be read from the data registers. Base+0 and base+1 for 8 bit transfer. For the 16 bit transfer, base+0 is also used --16 bit PC bus only. Upon the end of conversion, the interrupt or DMA request will be issued depending on the selection for reading conversion results.

    Reading conversion result - The PA-MA12(-H) conversion can be processed by the following methods:

      Method 1 : Polling the EOC status
      This method is the simplest method to do A/D conversions and read the data. However, this method ties up the CPU because one must keeping polling the EOC bit in the status register so that one can know when the A/D conversion is completed.
      Method 2 : Interrupt
      This method is more efficient than polling the EOC status, because upon completed conversion, the PA-MA12(-H) interrupts the CPU to read the conversion result. In other words, the conversion is done in the background, leaving the CPU to do more important tasks.
      Method 3 : DMA Transfer
      DMA transfer is the best way to do A/D conversions. This is because using DMA transfer imparts the fastest conversion speeds and does the conversions in the background. This leaves the CPU free to do more important jobs.

    Conversion status -

    Reading status - The status of the A/D can be read from two ports; (base+2 and base+3.) The base+3 port contains critical information for the setup and conditions of the A/D while the base+2 port contains information on the selected channel.

    Maximum conversion speed - The maximum conversion speed for multi-channel conversions are :

    Conversion Method PA-MA12 PA-MA12-H
    Pentium/133 80486/100 8088/8 Pentium/133 80486/100 8088/8
    Polling EOC 20KHz 15KHz 8Hz 25KHz 17KHz 10KHz
    Interrupt 45KHz 40KHz 15KHz 45KHz 42KHz 20KHz
    DMA 50KHz 50KHz 50KHz 100KHz 100KHz 100KHz

    Analog Output (D/A)

    The PA-MA12(-H) provides one voltage output channels 12 bit 10us digital to analog converter.

    DAC block diagram -

    Data register - The PA-MD12(-H) uses 2 I/O ports to control D/A conversions. The ports are base+4 through base+7. Using 2 ports per channel enables the user to send a 12-bit word to the D/A converter using an 8-bit bus without getting glitches on the output. Here is an example of the data register scheme. Say a user wishes to convert the digital value from 1AFH to 1B0H to an analog value. Using the standard approach of sending 8 bits at a time would result in a glitch on the output at the digital values 1AFH-1A0H-1BFH (sending LSB first, then MSB) or 1AFH-1BFH-1B0H (sending MSB first, then LSB). However, using the PA-ST12(-H) one would write the 0H (4 least significant bits) to the temporary register (base+4 ). Next, the user would write 1BH (8 most significant bits) to the output port (base+5). Upon writing the MSB to base+5, the data in the temporary register is automatically sent to the output, thus, both MSB and LSB arrive at the D/A simultaneously (i.e. no glitch).

    D/A conversion - D/A conversion is accomplished using a 12 bit D/A conversion chip. The 12-bit words are sent from the data bus and a temporary register simultaneously. This enables a 12-bit word to be sent from an 8-bit data bus without getting odd glitches on the output.

    The signal connector - The connector for D/A output signals is the same 37 pin male D-type connector used for the A/D. The A/D and D/A share the same connector.

    Digital I/O

    The PA-MA12(-H) features a digital I/O controller - 8255. It has 24 digital I/O lines that are divided into three 8-bit ports. Each port can be programmed as either input or output. All digital I/Os are configured as Expansion Data Interface (XDI). A variety isolated I/O expansion boards are available.

    The digital I/O connectors - There are three connectors for the digital I/O. Each consists of a 20 pin dual-in-line box header.


    Port Default Direction Function
    +0 02E0H I/O read A/D LSB data
    I/O write Start A/D conversion
    +1 02E1H I/O read A/D MSB data
    I/O write None
    +2 02E2H I/O read A/D channel select
    I/O write
    +3 02E3H I/O read A/D status
    I/O write A/D command
    +4 02E4H I/O write D/A 1 LSB data
    +5 02E5H I/O write D/A 2 MSB data
    +8 02E8H I/O read Digital I/O 1 (8255 Port PA)
    I/O write Digital I/O 1 (8255 Port PA)
    +9 02E9H I/O read Digital I/O 2 (8255 Port PB)
    I/O write Digital I/O 2 (8255 Port PB)
    +10 02EAH I/O read Digital I/O 3 (8255 Port PC)
    I/O write Digital I/O 3 (8255 Port PC)
    +11 02EBH I/O read 8255 Status Register
    I/O write 8255 Command register
    +12 02ECHI/O read8254 counter 0 data
    I/O write
    +13 02EDHI/O read8254 counter 1 data (A/D timer conversion)
    I/O write
    +14 02EEHI/O read8254 counter 2 data (A/D timer conversion)
    I/O write
    +15 02EFHI/O read8254 read-back status
    I/O write8254 command


    Shipped with this board are Utility, Library and Sample Programs. These programs are included at no additional expense with this product.

    Utility Program - This program will provide comprehensive testing of various functions of the board to ensure proper operation.
    Library And Sample Programs - The library program provides the interface to Turbo-C, Microsoft Quick Basic, Microsoft Quick C, Microsoft GW-BASIC, IBM BASIC and Assembler.
    Labtech Notebook Driver - A Labtech's Notebook driver interface is available as an optional product.
    Window Driver - Window 3.1 and Window NT driver interface is available as an optional product.


    Analog Input (A/D)
    Resolution 12 bits
    Input channel 16 channels (single-ended)
    8 channels (differential)
    Input voltage range -5V to +5V, -10Vto +10V
    0V to +5V, 0Vto +10V
    Accuracy 1 Bit
    Conversion time 20us, 50KHz (PA-ST12)
    10us, 100KHz (PA-MA12-H)
    Overvoltage 35V
    Gain controller 1, 2, 5, 10, 20, 50 or user define by
    H/W jumper setting
    Conversion method S/W trig
    External clock trig
    Internal 8254 timer trig
    Connector 37 pins D-type male connector
    Analog Output (D/A)
    Resolution 12 bits
    Channel l2
    Output voltage range -5V to +5V, -10V to +10V
    0V to +5V, 0V to +10V
    Accuracy 1 bit
    Conversion time 10us
    Connector 37 pins D-type male connector
    Digital I/O
    Controller 8255
    Number of input lines 24 lines total
    Logic family LSTTL
    Fanin load 1/8 LSTTL load
    Fanout drives 10 LSTTL loads
    Counter Timer (CLK)
    Controller 8254
    Counters 3 16-bit down counter
    2 for A/D timer conversion
    Clock source 4 MHz
    Input/output type TTL
    Interface Characters
    Compatible bus IBM PC and compatibles
    Data path 8 bits or 16 bits
    Interface type 12 Bit I/O mapped
    I/O location occupied 16
    Port address range 100H to FF0H
    Interrupt IRQ2,3,4,5,7,10,11,12,14,15
    Interrupt source A/D end of conversion (EOC)
    DMA DRQ 0,1,3 (8 bit)
    DRQ 5,6,7 (16 bit)
    DMA Source A/D end of conversion (EOC)
    Power requirement/consumption 1.1A /+5V)
    Operating temperature +5 ° C to +5 ° C
    Storage temperature -25 ° C to +85 ° C
    Humidity 0 to 90% non-condensing
    Weight 270 g
    Dimension 33.6 x 12.6 x 2.0 cm

Copyright © 1996 - 2000 by Acqutek Corporation, Inc.