Josh I posted? ?photo? of? a manual? we? had? ?a long? time? but? not? too long if? you?
want? to search? the? ?cctalk? here..?Also? always? wondered? which? plant built in...?is?
this? same? ?basically as? a? pbp 8? or? ?is? it? just that? they are both? 12
bits???Thanks? Ed#?In a message dated 9/29/2020 11:26:36 PM US Mountain Standard Time,
cctalk at
classiccmp.org writes:?
Hi all --?This is a long shot, but I was curious if anyone might have information onthe
Motorola MDP-1000 minicomputer.? I picked one up recently and I'mworking on restoring
it.? Of particular interest is the power supply, whichis external to the processor and
which I am missing.? I think I have thevoltages worked out (+/-5V and +/-15V), but there
are a number of othersignals on the power supply connector that I'm unsure of at the
moment.?I've put a few pictures up
here:?https://1drv.ms/u/s!Aqb36sqnCIfMpIVYmzKjFnsT3nHh8w?e=b2iqqv?I'll note that this
isn't technically an MDP-1000 -- it's labeled as anMDP-6650 on the rear.? I
suspect that this is a ruggedized version of the1000 intended for harsher environments.?
The front panel of mine appears tobe identical to the drawings of the MDP-1000 in the
manuals I have.?It also came with a binder of documentation (but alas no schematics)
thatI'll be scanning soon and getting off to Al.? It's an odd little system --5
12-bit registers, a 12-bit ALU, and a 12-bit Instruction Register, butthe memory is 8 bits
wide.? Instructions are packed into two bytesnormally, but there's a special 64-byte
region of memory that can be usedto store "shared bytes," which allow encoding
certain instructions into asingle byte, taking the other byte from the shared region.?
I've never seenanything quite like this.? I wonder why they didn't just use 12-bit
widememory...?Also the process for using the front panel to examine and deposit memory
isinsane.? Here's the instructions for reading a memory location; it's 10steps.?
Depositing is 17.?https://1drv.ms/u/s!Aqb36sqnCIfMpIVWThgwlxgCMQo59A?If anyone has
anything on this, let me know.? Not expecting much, but it'sworth a shot.- Josh