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Posted By

Hypex
on 2017-08-07
10:40:24
 Re: Possible 8501 replacement kit?

The only concern is the missing port line that is worked around in custom ROM. That said, I wonder if an 8502 converter would be feasible? This has the 7 lines we need and there are sources of 8502 which may be cheaper. But the the odd placement of port bit 5 missing on the 8501 may disrupt this arrangement with bit 5 existing on the 8502 but missing bit 7. So that might be better than a 6510 but still not perfect.

Given that WDC looks like they still produce 6502 derived CPUs maybe it would be best to simply adapt one of those and put it on a compatible PCB. Since it would be a new source. Should be easier than trying to do an FPGA based 8501. Though WDC do provide HDL files.

I have found replacement PLAs here:
http://www.ebay.com.au/itm/C16-4-or-1551-PLA-Commodore-16-plus-4-chip-251641-02-251641-03-equivalent-/191782739112?hash=item2ca7245ca8:g:XJ0AAOSwHnFV03nj

http://www.ebay.com.au/itm/PLA-251641-02-for-Commodore-Plus-4-Commodore-16-and-Commodore-116/182691475391?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

If only one of these could be made up to replace the CPU. Like you said there is a WIP for the TED. The FPGATED.

I have a C16 here that is socketed on CPU but didn't know some Plus/4's has it soldered on board.



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