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Posted By

TLC
on 2007-11-22
08:10:43
 Re: Drean Commodore 16 details -- finally...

About the EPROM chip: back then, mask-programmed ROMs, microcontrollers and other programmable chips were pretty common. As development would have been hard and slow with mask-programmable ROMs, the manufacturers usually offered EPROM-versions of the respective mask-programmable chips (you can check, for example, the Intel 8048 microcontroller, whose EPROM-version is the 8748 and so on)... maybe, the MC68766C is a similar equivalent for the mask-programmed 2364.

(Back then, manufacturers rarely used EPROMs in production machines, as they were expensive).

As far as I know, by that time the industry just had a standard pin-out for ROM and EPROM chips, and only Motorola and MOS manufactured chips like the 2364 (which is a non-standard, 24-pin 8k*8 ROM, unlike the "standard" 2764 which had 28 pins). Later they implemented standard pin-outs, too... (the 23128, the 16k*8 bit mask-programmed ROM that you'd also find in the Plus/4 is fully pin-compatible to the standard 27128 EPROM, at least).



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