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A project log for 74HCT6526

Building a Drop-In Replacement for the MOS6526. Sponsored by PCBWay

daniel-molinaDaniel Molina 05/14/2023 at 16:450 Comments

As this project is nearing its fifth anniversary, some celebration was in order. But before that, I needed to make it look prettier.

What you are looking at is B3. It houses both ICR and SDR and is both the densest packed board and the trickiest one to get 100% correct. You can see there are several connections amended, but it was for a good reason.

The 74HCT6526 is now passing some tests of the VICE Test Suite. This is a nice indication that it is cycle-exact! I can also switch it from OLDCIA to NEWCIA with the flick of a switch.

There are still some tests that are failing, but I'm pretty much there.

Also, B4, housing TOD, has been completely designed now. We're still waiting for production though.

Stay tuned!

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