EPROM Question

[ECMnut at aol.com]

Thanks Digger!
glad to see you're still out there!
Mike V
 
>  Date: Thu, 26 Oct 2000 23:38:19 EDT
>  From: ECMnut at aol.com
>  Subject: EPROM question
>  
>  I got some 27c128 chips from a friend, for
>  use in our 749 ECMs.  I was previously using
>  27128a-200
>  chips.  Are the 27C128s fast enough or will I be
>  burning "limp home" specials?  They are AMDs
>  and don't have a speed number on them.Thanks,Mike V- 
>  -----
>  
>  Nope, they should work fine, as long as they're not
>  *really* slow. (Which would be odd for CMOS)
>  
>  The C is for CMOS, the transistor technology the chip 
>  is based on. They're normally faster parts than the
>  non-C versions.
>  
>  Due to the technology differences, the C chips have
>  different thresholds for "High" and "Low" than do
>  normal TTL chips. In practice, though, you'll never
>  have issues with it.
>  
>  I've used the following successfully in the 749:
>  
>  27c128
>  27c256
>  27c512
>  27128
>  
>  AMD/TI/National seem to work the best. I have had
>  issues with NEC parts.
>  
>  A side note...
>  
>  I'm having issues trying to get the ATMEL AT29C256s
>  to burn properly on the Pocket Programmer. Shannen
>  and I tried to make them work at the EFI POWWOW, but
>  didn't have much luck. The 512 versions I had worked
>  fine.
>  
>  For those that have used them, what did you use to 
>  program them, and what version was the S/W? The PP
>  seems to have weird version control, as the later 
>  numbered versions have fewer chip types than some 
>  of the earlier ones.
>  
>  Thanks,
>  
>  Dig
>  turbodig at yahoo.com
>  
>  
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