I installed all the fixes into the PCB design, and decided that, just maybe, I should check to see if it worked as Central Memory.

Arrgggghhh! It doesn’t.

I noticed yesterday that address bit 10 & 11 LED’s were backwards, and I just found that I had swapped them at the module pins. It is fixed on the next revision.

OK, now I am really confused: when I have the new memory in 5A01, bit 2 in bank 10 doesn’t work well. Swapping sense amps does nothing. Moved it from 5A01 to 5D01 and it works fine. I have seen it fail there, but not in the last half hour. I may need to decrease the output limiting resistors to help the sense ampllifiers.

A weekend has passed, and the new module still seems to work in 5D01. I may finish the layout, and build another round of boards. I am pretty sure I can fix the sense problems with resistor value changes.

Here is a closer view of the module as it currently exists:

Bruce Sherry 4/3/2017 8:22:32 AM