[Coco] What do you use for pull-up and pull-down TTL resistor values? (LS series) (coco related project but possibly OT)

[Joel Rees]

2019年4月23日(火) 10:28 James Ross <jrosslist at outlook.com>:

> ...


I did actually buy a couple of Z80's (along w/ the Motorola CPUs) that can
> be clocked at 20 MHz which I want to play with (Oh no, heresy, not zed
> 80's!)!


Thumbs-up on that. Good to know different ways to do things.

IF I keep at it, eventually, I want to play w/ the MC68000 series starting
> w/ the 68008 ...
>

That's backwards. In fact, ... well, at any rate, do the 68K before the
68008.

Motorola really should have made a 16 bit 6809 instead of an 8 bit 68K,
years before some manager at Hitachi hinted to an intern while at a
business meeting at a bar that hidden extensions to the 6809 would be a
good study project.

I am really doing this so I can create that ultimate Real Time Clock! (RTC)
> ... (Insert evil laugh, here!) :)
>
> James
>

If you want to do that with a CPU, the 6801, or (if you can find them) the
6805 or its descendants (68HC08, not 6808) would do quite nicely.
Everything on one chip.

Or just do a clock without CPU in programmable logic.

>