3: REGISTER ARCHITECTURE
All of the programmable functions of the CIO-DAS801 and 802 are accessible through the control and data registers.
3.1 REGISTER LAYOUT
The CIO-DAS801 / 802 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 Uni-
versal Library routines.
To write to or read from a register in decimal or hexadecimal, 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
Each register has eight bits which may be a byte of data or eight individual bit
read/write functions. 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 is 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. Summaries of the registers and
their read and write functions are given on Tables 3-1 through 3-6.
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