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APPENDIX C
CIU-930 COMPUTER INTERFACE UNIT
GENERAL
The CIU-930 provides the interface for the DATANET-30 and a Compatibles/200 information
processing system and is used to transfer 21-bit words between them. The words are transferred
in parallel.
The CIU-930 connects into any channel of the DATANET-30 buffer selector in the
same manner as any other DATANET-30 buffer.
On the processor side, the CIU-930 connects
into any priority control channel.
The buffer selector address of the CIU is specified by the
wiring of the buffer selector address plug for the CIU module. There is no DATANET-30 hard-
ware restriction on the number of CIU' s which may be used, other than the physical space
occupied.
Each CIU-930 occupies one module.
The CIU is asynchronous.
It
has no service
rate and is program controlled.
CIU-930 INSTRUCTIONS
Following are the CIU-930 instructions:
Register Transfer
TRAR, B
Five things are accomplished (see illustration below):
1.
The data word contained in the CIU data register is transferred to
B:
CIU (18 - 1)
to
B
(18 - l), CIU (19) to control bit 1 flip-flop, CIU (20) to control bit 2 flip-flop and
CIU (21) to control bit 3 flip-flop.
2.
The CIU data register is reset.
3.
The address register is increased by 1 and transmit mode is set (DEF2).
4.
The transfer of another word is initiated.
5.
The CIU is put in the busy condition.
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C-1
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