LSI-11/2 microcode source
h.wolter at sympatico.ca
Thu Mar 3 01:20:40 CST 2005
"Eric Smith" <eric at brouhaha.com> replied:
Subject: Re: LSI-11/2 microcode source
darn - I was hoping it was simpler! too bad the PLAs can't
be deduced from the native microinstruction set/ISA..
knowing the binary contents of the first MICROM would be
enough for me.. I guess the addresses need only to be sequenced,
data read (with an analyzer) while providing the odd voltages and
multiphase clocks... unless someone out there has the listing ;)
my M7270 contains a control chip 1611-H 21-16890-00 (8015 date),
and CP1621B14 data chip while my
M7264 has a DEC badged ceramic 1611A 21-11549-01 (7717 date)
The AM100 appears to have a1611B. I assume these are diff. mask sets.
What the WD1600 stock set use? The Pascal Microengine?
> Heinz wrote:
> > Alternate anyone have info on reading out the WD PMOS roms?
> Reading the MICROMs wouldn't be that difficult. But it's not the
> whole story. The control chip has two metal-mask PLAs ("translation
> arrays") that can cause PC changes even when the current microinstruction
> is not a branch, based on two 8-bit translation registers and various
> other inputs.
> You can't, because the translation arrays are different in the LSI-11,
> Pascal Microengine, and WD-16. The data path chip of the Pascal
> Microengine and WD-16 are the same, but I'm not 100% certain that it's
> the same as that of the LSI-11.
> Also, the system-level interface of the LSI-11 and Pascal Microengine
> are different. There are four bus control signals from the MICROMs that
> get decoded for bus control, and they are not used identically in the
> LSI-11, Pascal Microengine, and WD-16. Even if you swap the control
> chip along with the MICROMs, the Pascal Microengine doesn't know how to
> talk to a Qbus.
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