Measurement Computing CIO-DAS16 - Manual (Page 22)

4 CIO-DAS16 CONTROL & DATA REGISTERS
4.1 INTRODUCTION
The CIO-DAS16 is controlled and monitored by writing to and reading from 20 consecutive 8-bit I/O addresses
(registers). The first address, or BASE ADDRESS, is determined by setting a bank of switches on the board.
Register manipulation is best done by experienced programmers since most of the CIO-DAS16 functions are
implemented in easy-to-use Universal Library™ routines.
The register descriptions all follow the format:
CH1 CH2 CH4 CH8 A/D12
LSB
A/D11 A/D10 A/D9
0 1 2 3 4 5 6 7
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 4-1):
Table 4-1. Register Bit Weights
80 128 7
40 64 6
20 32 5
10 16 4
8 8 3
4 4 2
2 2 1
1 1 0
HEX VALUE DECIMAL VALUE BIT 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 4-2. Within each register are eight bits which may
constitute a byte of data or eight individual bit read/write functions.
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