Diamond Systems 16-Channel 12-Bit Analog Output PC/104 Module, RUBY-MM-1612 Ruby-MM-1612 I/O Map

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6. I/O MAP

Ruby-MM-1612 occupies 8 consecutive 8-bit locations in I/O space. For example, the default base address is 300 Hex (768 Decimal); in this case the board occupies addresses 300 - 307 (768 - 775). The first 2 locations are used individually for each analog output channel. Since analog output data is 12 bits wide, it is broken into two bytes. The first byte contains the 8 least significant bits (called the LSB) of the D/A data, and the 4 lowest bits of the second byte contain the 4 most significant bits (called the MSB) of the D/A data. The 4 highest bits of the second byte are not used.

The DACs are updated all at once when Base or Base+1 is read. The value read from these locations is not predictable and not meaningful. Only the act of reading from the board is required to perform the update.

 

Ruby-MM-1612 I/O Map

Base +

Write Function

Read Function

 

0

DAC LSB (all DACs)

Update all DACs simultaneously

1

DAC MSB (all DACs)

Update all DACs simultaneously

2

DAC channel register

NA

3

External trigger enable

NA

4

Digital I/O port A data

Digital I/O port A data

5

Digital I/O port B data

Digital I/O port B data

6

Digital I/O port C data

Digital I/O port C data

7

Digital I/O control register

Digital I/O control register

Reset information:

A system hardware reset will also reset the board.

During a reset, the following occurs:

∙All analog outputs are set to mid-scale (0V for bipolar ranges and 1/2 full-scale for unipolar ranges).

∙The external trigger register is set to 0, disabling external trigger.

∙All digital I/O lines are set to input mode.

The next chapter describes all registers on the board. You should familiarize yourself with these registers in order to get a complete understanding of the board’s operation.

Copyright 2001 Diamond Systems Corp.

Ruby-MM-1612 User Manual V1.1 P. 9

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Contents
RUBY-MM-1612 Table of Contents Description O Header Pinout Signal Name DefinitionBoard Configuration Base Address Configuration Header J5 Position Hex DecimalBase Address Adjustable Reference Voltage Analog Output Range ConfigurationOn-Board Reference Full-Scale Voltage Selection Full-Scale VoltageAnalog Output Configuration Header J4 Range RUBY-MM-1612 Board Drawing Reset information Ruby-MM-1612 I/O MapBase + Write Function Read Function Register Definitions Base + 0 or 1, Read Update DACsBase + 0, Write DAC LSB register Base + 1, Write DAC MSB registerBase + 3, Write External trigger register 82C55 Digital I/O Chip Operation Configuration Register82C55 Register Map DefinitionsAnalog Output Ranges and Resolution Full Scale 1LSBFull Scale 10. D/A Code Computation Offset Binary Coding for bipolar output ranges LSB = 1/2048 x Full-Scale VoltageOutput Code Explanation Output Voltage for ±5V Range HOW to Generate AN Analog Output Hardware Update CommandTo generate an analog output on one or more channels Two channel output Examples Single channel outputCalibration Procedure Miscellaneous SpecificationsOrdering Information FeaturesDescription Pinouts82C55A Pin Description Functional DiagramData Bus Buffer 82C55A Functional DescriptionRead/Write and Control Logic Group a and Group B Controls82C55A Mode SelectionOperational Description Ports A, B, and COperating Modes Single Bit Set/Reset Feature FigureInterrupt Control Functions Inte Flip-Flop DefinitionMode 0 Basic Input Mode 0 Basic OutputMode 0 Configurations Control Word #4 Control Word #8 Input Control Signal Definition STB Strobe InputIBF Input Buffer Full F/F Intr Interrupt Request Output Control Signal DefinitionBi-Directional Bus I/O Control Signal Definition Mode 2 Strobed Bi-Directional Bus I/OOutput Operations Input OperationsMode Control Word Mode 2 Combinations Current Drive Capability Special Mode Combination ConsiderationsReading Port C Status Figures 15 Applications of the 82C55A