Measurement Computing CIO-DAC02/16 - Manual (Page 10)

5 DATA REGISTERS
The CIO-DAC02/16 has four analog-output data registers. There are two for each
channel, one for the lower eight bits and one for the upper eight bits. The first address
(BASE ADDRESS) is determined by setting a bank of DIP switches on the board.
The information presented in this chapter is intended for experienced programmers. If
you are not familiar with register manipulation, we encourage you to use the Universal
Library.
To write to or read from a register in decimal or HEX, the following weights apply:
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
The registers and their function are listed on Table 5-1.
Table 5-1. Data Registers
Initiate simultaneous update. D/A 1 Most Significant Byte BASE + 3
Initiate simultaneous update. D/A 1 Least Significant Byte BASE + 2
Initiate simultaneous update. D/A 0 Most Significant Byte BASE + 1
Initiate simultaneous update. D/A 0 Least Significant Byte BASE + 0
READ FUNCTION WRITE FUNCTION ADDRESS
The bits of the registers are labeled as follows:
BASE + 0 and BASE +2 (LEAST SIGNIFICANT BYTE)
DA16
(LSB)
DA15 DA14 DA13 DA12 DA11 DA10 DA9
0 1 2 3 4 5 6 7
BASE + 1 and BASE +3 (MOST SIGNIFICANT BYTE)
DA8 DA7 DA6 DA5 DA4 DA3 DA2 DA1
(MSB)
0 1 2 3 4 5 6 7
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