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Old 16th Apr 2018, 1:31 pm   #9
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,287
Default Re: MK14 schematic revisions

Quote:
So, will you now work these changes into your replica?
To be honest I'd worked out how they might have done it whilst not getting to sleep (insomnia isnt all bad!) before I read your document, but it confirmed my thoughts.

I'd like to roll these changes in, as I might as well build a rev 5, but I might need one of the AND gates for the RAM enable line, actual MM2111 ram chips are proving hard to find and the pin-compatible(ish) IM65X62 that I have managed to acquire from Poland requires the enable pin to be pulled low in read and write cycles. Unless I can liberate another of the inverters from the reset logic and invert the 'rds or wds' line, but I'm not sure the SCMP will like a slow rising reset pulse!
I might have to breadboard up a test circuit to check it can be made to work timing wise!
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