Re: EPROMS and EEPROMS

From: Nicolas Welte; address is valid for replies (Re:) only! (welte_spam_at_freenet.de)
Date: 2002-11-30 10:05:09

Niklas Ramsberg wrote:
> Since it can be used to program EEPROMs, I started to think it might be
> a good idea to use EEPROMs instead of EPROMS. That way, I won't have to
> invest in an EPROM eraser. I'll mainly use it to experiment with
> different kernals in my C=s (C64, C128, VIC-20, Plus/4). Is it possible
> to substitute e.g. a 28C256 for the 23256 or 23128 chips in the C128 or
> for the 24 pin ROMs in the C64 and VIC-20 (provided I rewire the pins
> that don't match)?

As far as I know, the 28Cxxx series is completely pin compatible with the 
27Cxxx series. I have an EEPROM programmer for the C64, the DELA EPROMMER II. 
EEPROMs are even programmed with the same programming alghorithm as EPROMs, 
only the erasing of the chip needs a special new alghorithm.

If you need a 28pin to 24pin adaptor (or 32 to 28, 28 to 28, or 32 to 24), 
have a look at my projects page. It also contains a Flash ROM programmer for 
6502 computers. Since its main purpose is not the programming process, only 
very few devices are supported, actually it's only the Atmel 29C010 and 
compatibles. Still, since these chips are much cheaper now than EPROMs, it's 
a better idea to use those to replace a kernal. You can put 16 different 
kernals in one chip :-) Oh, the address: http://people.freenet.de/x1541

There are also simple Flash programmers for the C64, I think there's one on 
Funet and another one on www.6502.org.

Nicolas



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