Measurement-computing PC104-DAS16JR/12 Instrukcja Użytkownika Pobierz pdf (Strona 15)

3 REGISTER ARCHITECTURE

3.1 CONTROL & DATA REGISTERS

The PC104-DAS16Jr/xx is controlled and monitored by writing to and reading from

16 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 with a

specific need for low level control. If this is the case for you, use the information that

follows to write your own code. Otherwise, we strongly suggest you consider using

the Universal Library™ instead.

The register descriptions all follow the format:

CH1CH2CH4CH8A/D12

LSB

A/D11A/D10A/D9

01234567

The 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 following weights apply:

Table 3-1. Bit Weights

801287

40646

20325

10164

883

442

221

110

HEX VALUEDECIMAL VALUEBIT POSITION

To write control 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 3-2.

1 2 ... 10 11 12 13 14 15 16 17 18 19 20 ... 31 32

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Measurement-computing PC104-DAS16JR/12 Instrukcja Użytkownika Strona 15