EPROMs are programming AOK

[Peter Gargano]

TRAX wrote:

> EPROM, 32KX8 90NS 28CERDIP 27C256-90 $3.99

Can you tell me the manufacturer of this part, please?

> > The problem is that you may have only partially
> > programmed each bit
> 
> Is this possible?  I thought that it was either 0 or 1.  How can a bit be
> partially programmed?

I uploaded the following Nat. Semi. application note about programming
EPROMs. It explains how you can have a partially programmed bit, and how
that bit may read as a 0 or as a 1 under different circumstances.

  ftp://ftp.diy-efi.org/incoming/NatSemiAN472.pdf

It also talks about partially erasing EPROMs, another topic recently
discussed here.

Peter

BTW - I could not convince either Fairchild, or Nat Semi to make the above
PDF available from either of their own web sites (Fairchild now handles
the EPROM business that was Nat Semi's.) So, although the document it 
copyright NatSemi 1995, I'm sure they won't mind it being available here.
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org