Programming 2708's

[Dwight K. Elvey]

>From: "Randy McLaughlin" <cctalk at randy482.com>
>
---snip---
>Intel changed the specifications of the 2708 a couple of times, later docs 
>state it does not require programming from address 0.
>
>I have changed individual bits (only from a high to low, to go from low to 
>high the entire chip must be erased).
>
>The later docs still state sequential writing but no longer require starting 
>at 0 but I have written non sequentially and can swear by that.  I wrote a 
>program that verified before writing to speed up programming, this skipped 
>many bytes and I used it to modify previously written EPROM's.  The buffer 
>in RAM was sequentially read but the writing was NOT sequential it would 
>skip bytes when a write was not needed.
>
>Any byte can have high bits changed to low even if they were previously 
>programmed.
>

Hi Randy
 I recall the primary reason they wanted one to go through
the entire cycle was that it gave the particular spot
that was programmed a chance to cool down. I'm not sure if this
was actually a real problem or just a suspected problem.
I may have been an electrical issue with space charge as well.
 Technically, you could skip locations that didn't need
programming but you should insert a delay equal to the
normal total time before programming the same location
again.
 Anyway, that is what I remember.
Dwight