Sinclair ZX80 / ZX81 Forums

[sirmorris]

Should an add-on always have buffers on the address and data lines?

I hope the answer's 'not always'. I don't want to add any more chips to my design because it's quite cosy enough as it is... I only have a small fan-out on the address and data lines but how much can be gotten away with?? I have RAM and EPROM, and the data lines also feed a microcontroller.

I can't afford to suck it and see. Once the boards are committed to fibreglass that's it. Does the panel think that a breadboard-built prototype would show any problems up? I have a gut feeling that if it works on a breadboard then it's certainly going to work on a PCB.

C

[KnightFire]

Does the panel think that a breadboard-built prototype would show any problems up? I have a gut feeling that if it works on a breadboard then it's certainly going to work on a PCB.

I would tend to believe that the resistance of the breadboard would be higher than the copper on a PCB; so yes, I believe your assumption to be correct.

However I tended to buffer all my add-ons anyway.

--
KnightFire
trying to remember what was 2nd nature some 26 years ago.

[sirmorris]

That's reassuring