2 Mar
2005
2 Mar
'05
11:20 p.m.
"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?
regards
h
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.
Eric