Thread: Mk14 vdu
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Old 12th Nov 2020, 7:02 pm   #894
Mark1960
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Join Date: Mar 2020
Location: Kitchener, Ontario, Canada
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Default Re: Mk14 vdu

Quote:
Originally Posted by SiriusHardware View Post
I can't get away with less than 156pF as far as I know (although I could try lowering the values back down in the direction of 100pF). At the moment I'm saying 156pF is the acceptable minimum, at least on my hardware.
An alternate for capacitors that might be a bit more healthy for the devices driving the bus might be to add a 74ls08 on the OrtonView. NENIN from PIC on one input, and NWDS from MK14 on second input, then the output to NENIN on the MK14. This would always allow an NWDS cycle to complete, though possibly not complete enough to avoid retry after release of NENIN. It would delay SCMP release of the bus by as much as 500ns, but I think Karen gave enough margin to allow that.
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