Measurement-computing PC104-DAS08 Bedienungsanleitung PDF herunterladen (Seite 12)

3 REGISTER ARCHITECTURE

3.1 CONTROL & DATA REGISTERS

The PC104-DAS08 is controlled and monitored by writing to and reading from eight

consecutive 8-bit I/O addresses. The first address, or BASE ADDRESS, is

determined by setting a bank of switches on the board.

Most often, register manipulation is best left to experienced programmers as most of

the PC104-DAS08 possible functions are implemented in easy to use Universal

Library functions.

The register descriptions follow the format:

CH1CH2CH4CH8A/D12

LSB

A/D11A/D10A/D9

01234567

Numbers along the top row are the bit positions within the 8-bit byte and the

numbers and symbols in the bottom row are the functions associated with that bit.

To write to or read from a register in decimal or HEX, the weights in Table 3-1

apply:

Table 3-1. Bit Weights

801287

40646

20325

10164

883

442

221

110

HEX VALUEDECIMAL VALUEBIT POSITION

To write control words or data to a register, the individual bits must be set to 0 or 1

then combined to form a byte.

The method of programming required to set/read bits from bytes is beyond the scope

of this manual.

In summary form, the registers and their function are listed on Table 4-2. Within

each register are eight bits which either constitute a byte of data or eight individual

bit set/read functions.

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 23 24

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Measurement-computing PC104-DAS08 Bedienungsanleitung Seite 12