EEPROM Wiring

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EEPROM Wiring
by Dendy on 2011-08-03 (#82429)
Just a quick question... Does an EEPROM needs a different wiring than an EPROM when used on a nes board? And if it does where can I find the pinout info?

Thanks!

by tokumaru on 2011-08-03 (#82432)
That depends on the chip... AFAIK, not even all EPROMs have the same pinout, so it's always a good idea to check pages like http://datasheetcatalog.com/ for the chips you have.

by koitsu on 2011-08-03 (#82436)
Generally speaking yes, they have different pinouts. You should always assume everything has a unique/different pinout and check pinout documentation before wiring things up (vs. just assuming).

by Dendy on 2011-08-03 (#82440)
Thanks guys, I just checked the data sheet and the pinout for SST27SF020 EEPROM seems to be the same as for EPROM 27C020...
So I think it should work...
Thanks for help!

by qbradq on 2011-08-04 (#82443)
Are you sure they are the same? Generally EEPROM's have a Write Enable line that EPROM's do not. You need to make sure on this point and tie the Write Enable line to Vcc, otherwise bad things might happen.

Also, this should be moved to the Hardware board.

by Dendy on 2011-08-04 (#82450)
qbradq wrote:
Are you sure they are the same? Generally EEPROM's have a Write Enable line that EPROM's do not. You need to make sure on this point and tie the Write Enable line to Vcc, otherwise bad things might happen.



Not very sure about that, but it looks very similar to 27C020 schematics

Image

by koitsu on 2011-08-05 (#82482)
Topic moved to NES Hardware and Flash Equiment forum.

by qbradq on 2011-08-05 (#82486)
Check pins 1 and 31 on your EPROM pinout. Those are the ones that are most often different.

by Dendy on 2011-08-05 (#82504)
qbradq wrote:
Check pins 1 and 31 on your EPROM pinout. Those are the ones that are most often different.


Here are two together: left EEPROM and right EPROM
Only difference is 32d pinout notation, on EEPROM is it Vdd and on EPROM Vcc. But both are 5V... Don't know if it make any difference. Next week I'll get the chips and will test them...

Image Image

by Dendy on 2011-08-26 (#83138)
UPDATE:
I finally got the SST chips today, and just made SMB2j repro with succes.
It works fine just as with normal EPROM chips! So, from now on I'm going to use EEPROM's!