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Old 8th Jun 2019, 12:18 am   #82
JohnBHanson
Heptode
 
Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 661
Default Re: Gemini 80-Bus System

Port e1 is status/control
Port e2 is data

If you wanted to you could probably connect an SD card directly to the scsi bus with just some level shifters. Looking at the scsi interface /req, C/D /MSG and /BUSY are input signals.

By tieing I/O you can set D0..D7 to be input or output - best to use them as output.

This provides you with 4 inputs and 8 outputs which should be enough to drive an SD card with some custom software. There are Sd card drivers available on the net for Z80.
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