Measurement Computing CIO-INT-32 - Manual (Page 12)

The first I/O address, or BASE ADDRESS, is determined by setting a bank of
switches on the board.
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
To write a control word 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. It will be covered in most Introduction To Programming books,
available from a bookstore.
In summary form, the registers and their function are listed on the following table.
Each register has eight bits which may constitute a byte of data or eight individual bit
set/read functions.
Control Status BASE + 7
Port A Port A BASE + 6
Port B Port B BASE + 5
Port C Port C BASE + 4
Second Z8536 Processor
Control Status BASE + 3
Port A Output Port A Input BASE + 2
Port B Output Port B Input BASE + 1
Port C Output Port C Input BASE + 0
First Z8536 Processor
WRITE FUNCTION READ FUNCTION ADDRESS
Refer to the Zilog Z8536 manual for programming instructions.
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