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SiriusHardware · 10th Nov 2020, 9:58 am

It's a good idea to put the latch into the upper range of the I/O port block as the 8154 only really uses a handful of addresses in that range but then the address decoding for the 8154 would have to be intercepted on the MK14 itself, requiring mods to the MK14. That's why I suggested knocking out one byte of the extra-extra RAM (0200-07FF) instead, so that it could be incorporated into the address decoding for that section which is off-board.

Capacitor placement: Yes, sort of, but since Tim's build and mine are physically different it's impossible for us to place them in exactly the 'same' place but I put mine on the threshold of the PIC PCB as he did, ie, the point where A8-A10 exit the PIC PCB.

10th Nov 2020, 9:58 am	#864
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,547	Re: Mk14 vdu It's a good idea to put the latch into the upper range of the I/O port block as the 8154 only really uses a handful of addresses in that range but then the address decoding for the 8154 would have to be intercepted on the MK14 itself, requiring mods to the MK14. That's why I suggested knocking out one byte of the extra-extra RAM (0200-07FF) instead, so that it could be incorporated into the address decoding for that section which is off-board. Capacitor placement: Yes, sort of, but since Tim's build and mine are physically different it's impossible for us to place them in exactly the 'same' place but I put mine on the threshold of the PIC PCB as he did, ie, the point where A8-A10 exit the PIC PCB.