After looking at datasheets for the 273 latches used and 74act74 flipflop used, the worst case propagation delay is something like 12.3ns. But my NAND gate ACT00 logic which is triggered by the same CAS signals has a...
Latest articles
PCBs have arrived!
Just in time for Christmas, the PCBs have arrived from China. I used Seeed Studio (Fusion PCB Service) and they look pretty good. Here’s the first look at them. I’m just about to solder one up, so wish me...
Found problems with incorrect footprints used for some chips
So I received all of the SMT parts today, and attempted to verify that I’ve used the right footprints for the parts. This was a worthwhile effort because I found a few different problems. Also, digi-key shipped me...
Moving from prototype on a solderless breadboard to PCB soon
So I’ve got a reasonable number of memory tests passing with the prototype solderless breadboard. There are some minor issues that are mostly related to the stability: Sometimes my memory board steps on the built...
Testing shows databit 10 is always stuck high on commodore amiga expansion
With help from Ralf on this comment I was able to Disable the memory by no-longer grounding PIN 32, and sometimes forcing CE high on the SRAM chip. Boot a workbench disk, and then break it on startup. Insert a disk...
