3 ms·
Yup, very reliable for low(ish) frequencies around 20MHz. I built 68010 and 68020 prototype systems using the DIL packages. Those were better for wire-wrap than
by nonrandomstring 4y ago
Yup, very reliable for low(ish) frequencies around 20MHz. I built
68010 and 68020 prototype systems using the DIL packages. Those were
better for wire-wrap than the later pin grid versions of the 020
because you didn't get such a density of wires fanning out. A great
text book we used circa 1990 was Alan Clements "Microprocessor Systems
Design" (PWS Kent). It's an almost faultless book based on his
practical systems lectures at Teeside Poly, full of schematics from
which you can build working 68000 computers using pairs of 8 bit DRAM
and EPROMS of the time.
- richrichardsson 4y agoThis is interesting. I presume in the example shown they stuck to 1MHz as it would be more reliable than clocking to the kind of speed you mentioned, again presumably because the nature of a bunch of discrete components meant the switching of logic levels imposed a hard limit? Another sibling mentioned the Amiga prototypes, I'm again presuming that the ~7MHz that that chipset ran at was well within the acceptable ranges for clock speed using discrete components?
- nonrandomstring 4y ago<grabs book and dusts-off failing pages...> On page pp 142-3 is the minimal config schematic that shows "oscillator module" (IC4) but it isn't in the BOM. However pp 108 (fig 4.2) shows it as 8MHz. IIRC it was a MAX 6 pin 4MHz module I used, later I cranked it up to 10MHz on a 8MHz 68k uP and it still worked. Crazy overclocking!
- kjs3 4y agoClements book is indeed excellent. I doubt I'd have been as successful homebrewing a 68k back in the day without it.