Modes 1-6 & 8.
PSI BOX Reference
Addressed Operation.
___________________
The PSI BOX acts as the IEEE controller and is the source
of all IEEE commands. It controls the flow of data on the IEEE
bus by addressing and un-addressing devices. Only one IEEE
device can be accessed when in this mode.
The address of the IEEE device that the PSI BOX accesses
is as set on the IEEE address DIP switches. The PSI BOX sends
a LISTEN command to the IEEE bus before each data byte is
sent.
If the Centronics input buffer of the PSI BOX becomes
full then it will hold the BUSY line high until the IEEE device
accepts data from the PSI BOX.
In Mode 5 the whole of the PSI BOX ram acts as the
Centronics input buffer.
Chapter 6
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