PDP11 M9301-Yx ROM dumps

Noel Chiappa jnc at mercury.lcs.mit.edu
Sat May 14 07:25:46 CDT 2016

    > From: Rob Doyle

    > the 'objcopy' utility in the Binutils package can translate between
    > binary, tekhex, srec, ihex, etc.

Right, but the problem is that I had dumps which were what the PDP-11 CPU
saw, but due to hardware oddities on the M9301 board, the _ROM contents_ were
diferent: bits 1-8 (_not_ 0-7, which would have been simpler :-) have to be
inverted. I'm not sure any existing tool could manage that!

Speaking of hardware oddities in the M9301, it seems the Tech Manual
(EK-M9301-TM-001) has an error: it seems to indicate that the first (low)
words in the PROM should contain the first words at 173000 ("address
locations 773000 .. are located in the lower 256 words of the PROM", pg. 2-7).

However, looking at the prints, the signal "765XXX L" is fed into the high
address bit of the PROMs, and looking at how it is generated (Fig. 2-8, pg.
2-8) it should be low when the low addresses (765xxx) are being read, so the
low addresses in the PROM should correspond to 765xxx?

Also, looking at Mattis' read-out of the actual PROMs, they have the code
that's at 773000 at 0x100 in the PROM.

So it does seem as if the PROMs aren't organized the way the Tech Manual


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