Close

Ø0 FTW!

A project log for ABN6502 SBC R1

Saving the planet, one obsolete chip at a time

anders-nielsenAnders Nielsen 05/11/2022 at 16:030 Comments

I can happily confirm that even on the NMOS 6502 Ø2B can be replaced with Ø0 if Ø1B is replaced with ~Ø0. 

This improves margins a bit and solves an issue on the NMOS 6502 that caused a few spurious writes - I guess my NMOS Ø2-pullup was not quite enough under all conditions. 

Either way - this is why R1 has three of the jumper positions next to the barrel plug. 

For the next revision this means I will probably throw away the buffering and just use Ø0 and it's inverted companion.  I still need the 74'14 for the reset circuit - but having four left over inverters is great!

Discussions