Measurement-computing CIO-DAS08-AOH Manuel d'utilisateur télécharger pdf (Page 13)

6 CIO-DAS08-AOx ARCHITECTURE

All of the programmable functions of the CIO-DAS08-AOx are accessible through the control and data registers, which are

explained here.

6.1 REGISTER LAYOUT

The CIO-DAS08-AOx 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.

Register manipulation is best left to experienced programmers as most of the possible functions are implemented in easy to

use Universal Library™.

The register descriptions use the following 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 hexadecimal, the bit weights in Table 6-1 apply:

Table 6-1. Byte 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. Data read

from registers must be analyzed to determine which bits are on or off.

The method of programming required to set/read bits from bytes is beyond the scope of this manual. It will be covered in

most Introduction To Programming books, available from a bookstore.

In summary form, the registers and their function are listed on Table 6-2. Within each register are eight bits which may

constitute a byte of data or they may be eight individual bit set/read functions.

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 31 32

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Measurement-computing CIO-DAS08-AOH Manuel d'utilisateur Page 13