tac@sei.cmu.edu (Timothy Coddington) (09/16/88)
I'm trying to copy a set of debug ROMs (Part # Motorola 133ABUG) and I've
had no success. Is there something I've missed?
The ROMs are for a single board computer (Motorola MVME133A-20). This is
how I judge success/failure: if I remove the ROMs, copy them, install the copied
version in the board and it doesn't go into halt state and I get the debugger
prompt, then I've succeeded. Otherwise, something went wrong.
The originals have the following part number: Fairchild MBM27C512-20
I've tried copying to both of the following parts without success:
Toshiba TMM27512D-20
and
NEC D27C512D-15 both pgm @12.5V
I'm using the following programmer: Data I/O 201. I know the Toshiba part
has been successfully programmed with downloaded data before. This is the
first time I've tried to do anything with the NEC part on this programmer.
Yes I do have permission to copy these chips!!
When the data is "L"oaded off the original I get a checksum. After I've
"P"rogrammed the blank (which I've checked to make sure is blanked) I get
the same checksum result.
Since the exact device setups are not available in the programmer for any
of the above parts I've tried the only two *512 device setups available.
Data I/O didn't promise anything when I called them, but they did say which
one should work (remember the toshiba part has been programmed before).
Is there something I've missed. It seems like the copy goes OK, but the
board doesn't boot! Is there something about the way some ROMs are
programmed that prevents them from being copied? Has someone run into this
problems before? suggestions?
HELP!!
HELP!!
Tim Coddington Software Engineering Institute, Carnegie-Mellon Univ.
Arpa: tac@sei.cmu.edu 412-268-7712 (h) 244-8557
Thanks for taking the time!berryh@udel.EDU (John Berryhill) (09/16/88)
Have you compared timing diagrams? John Berryhill
jim@trsvax.UUCP (09/16/88)
There are a few lines that the EPROM might be expexting programming/select signals on that the ROM socket does not provide (or provides the wrong voltage level or signal). I know it's vague, but it has bitten me before.
paul@Data-IO.COM (Paul Brownlow) (09/17/88)
In article <4088@louie.udel.EDU> berryh@udel.EDU (John Berryhill) writes: > > >Have you compared timing diagrams? > >John Berryhill The timing diagrams don't always tell the complete story (or the true story!). Different manufacturers' EPROMs will not always act the same, even though the spec sheets say they should. One common difference is in the order of the falling of /OE with respect to /CE. Some EPROMs will not output the data if /OE falls before /CE; others will not function properly if /CE is held low between address changes. Some EPROMs will work in all cases. All EPROMs work if the part is completely disabled between address changes; i.e. /CE and /OE are high at this time. /CE must then fall, followed by /OE. Read the part. raise /OE, then /CE. Move to the next address. In your case, you should probably try to find another EPROM made by the same manufacturer as the original. The programmer is writing the EPROM correctly; it's your system that can't read it. Paul -- Paul Brownlow Data I/O - FutureNet Redmond, WA ..uw-beaver!uw-entropy!dataio!paul "It's my snake! I trained him, I'm gonna eat him!"
rowley@inuxa.UUCP (David Rowley) (09/18/88)
> I'm trying to copy a set of debug ROMs (Part # Motorola 133ABUG) and I've > had no success. Is there something I've missed? I know on an apple computer although the ROM's are pin for pin compatible with a 2716 there is one small difference: one of the chip enable lines has been inverted. If you read the fine print of a data manual you will find this is an option: the polartity of the chip select lines. So.... maybe your lines are also inverted. But then again it seems if this were true you would have trouble copying the data to the EPROM programmmer.
markw@hpsal2.HP.COM (Mark Williams) (09/20/88)
The part number for the master EPROM (MBM27C512) is a Fujitsu P/N, not Fairchild as the original poster stated. Some Fujitsu EPROM's require a different programming algorithm/voltages than the rest of the industry parts; INTEL used to set a defacto standard, but Fujitsu and others are evolving new cells. Make sure you are using the right part number/algorithm for reading the master EPROM.
jim@trsvax.UUCP (09/20/88)
>/* Written 4:03 pm Sep 17, 1988 by inuxa.UUCP!rowley in trsvax:sci.electronics */ >> I'm trying to copy a set of debug ROMs (Part # Motorola 133ABUG) and I've >> had no success. Is there something I've missed? >But then again it seems if this were true you would have trouble copying >the data to the EPROM programmmer. If the ROM was deselected wouldn't the data look like FF if the programmer had pullups? (or at least constant). If that is the case, it should verify just fine as it would still be deselected the next time. Have you looked at the data in the EPROM ?.