Wanted: ASM-48 for Intellec MDS-2

Eric Smith spacewar at gmail.com
Sun May 17 16:07:27 CDT 2015

On Sun, May 17, 2015 at 1:55 PM, Alexandre Souza
<alexandre.tabajara at gmail.com> wrote:
> As far as I remember, + 25 isnt used for rom reading. You can read any
> 8048/8049 as 8748/8749 with no danger. And they have no soft protection. So
> any uc *48 and *49 can be copied.

25V isn't used for reading the 8041 and 8048, but it *is* used for
reading the 8741, 8741A, 8748. That can be seen in the Intel
datasheets as well as the MCS-48 and UPI-41 user manuals.  I've also
verified the presence of 25V during  read on multiple device

I have in fact read some 8048 and 8049 parts as 8748 and 8749,
respectively, but only with parts that I had spares of, since the 8048
and 8049 are NOT rated for use of +25V to read, and instead are
supposed to be read with EA at +12V. While it's reasonably plausible
that putting +25V on EA won't damage an 8041A, I don't have another
instance of the 8041A with the same code, so I'm not willing to risk

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