Retromaster’s Electronics Projects

…related to old computers and other assorted stuff…

Amstrad CPC6128 with UFE

Posted by retromaster on June 12, 2010

Before moving on to manufacturing the new PCB revision, I wanted to make sure that there were no showstoppers that could prevent operation with the major target hosts of the UFE. Or, that if I encountered any problems, I could fix them in the next PCB.

So, enter my tests with the CPC6128. The video is working fine. I’ve added .DSK read support to the firmware, which also seems to work fine, but the diversity of the .DSK images out there (including those with copy-protection) necessitates more testing. But the basic functionality is working. After a few small modifications to the firmware, dual drive support also works fine. In the UFE settings menu, the user needs to choose the CPC mode for correct handling of SEL lines.

Amstrad engineers made some interesting design choices with the CPC6128. The internal floppy connector is not standard. None of the connectors have SEL lines for both drives, and according to the schematics, SEL0 is actually SEL1 inverted. Nevertheless, UFE operation turned out to be a little problematic with the SEL1 connection from the external connector, so I took the SEL0 line from the internal connector with a patch cable. The same will need to be done for the MOT line.

Write support for .DSK images is missing at the moment and since there is no keyboard daughterboard for the CPC6128 yet, I’ve used my previous button interface to test things. Both of these features will need to wait until after I am done with the next PCB revision.


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