Measurement Computing CIO-DAC16-I - Manual (Page 11)

4 REGISTER ARCHITECTURE
The CIO-DAC##-I is a simple board to understand. All control and data is
read/written with simple I/O read and write commands. No interrupt or DMA
control software is required. Thus, the board's outputs are easy to control directly
from BASIC, C or PASCAL.
The CIO-DAC##-I has two control and analog output registers.
The first address, or BASE ADDRESS, is determined by the setting of a bank of
switches on the board.
The register descriptions all follow the format:
A0 A1 A2 A3 A4 A5 A6 A7
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 each bit.
To write to or read from a register in decimal or HEX, the following weights apply:
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
7