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
