12 Aug
2010
12 Aug
'10
12:22 p.m.
From: ian_primus at yahoo.com
---snip---
So, carefully reading the datasheet, I notice that the 27c160 wants a program pulse of
50us. The chip that the programmer thinks it's programming, a 27c040, uses a
programming pulse of 100ns. The programming waveforms between a 27c160 and a 27c040 look
the same to me, besides that. But it would seem that my problems lie with the waveform
being incorrect, and newer chips being less picky about it than the older chips of the
same part number.
Now, I'm stumped. I *really* want to make this programmer program these chips. It
does everything else properly, including program 27c322's with this adapter. Now, I
know the adapter is wired correctly, because I have programmed newer rev 27c160's
properly, and they have worked perfectly in their intended purpose. The adapter is wired
up such that in 27c322 mode, the programmer is used as if it were a 27c080, and in 27c160
mode the programmer is used as if it were a 27c040. I did it this way due to the pinouts
of the devices and the required programming algorithms.
Basically, I am wondering if any of our resident gurus have seen behavior like this with
EPROMs, and if there may be anything I can do to shorten pulses, buffer, or something to
get this to program... or, if anyone just *happens* to have the source code to the EMP
software laying around somewhere...
Hi
I was giving this some thought.
What problem are you actually having? Are you getting cells that
don't program or are you seeing cells that are being programmed without
there bing a bit '0' in that location.
One thing to check is the quality of the socket used. Most older
Zero insertion sockets use metal that does corrode over time. These
do need bernishing.
This usually causes failures in connecting address or data line.
If it is failing to program, increase the voltage a little ( worst you can do
is blow out the part ).
If you are seeing bit that are programmed to zeros that shouldn't be,
try reducing the voltage.
Also turn off any manuufacture recognition and use generic programming.
As I said, the most common problem is bad contact on the pins. The socket
could have corrosion and the sides of the pins could also have corrosion.
Doing a dump after a programming error can show quite a bit about what
was happening.
Dwight