MMD-2 notes

I just got word (thanks Shawn!) that an electronics shop in California has MMD-2 boards, stripped of some parts, available for something like $10 or $15 each. I haven't seen them myself, so I can't vouch for them in any way. If you are interested, contact Haltek Electronics:

Haltek Electronics
1062 Linda Vista Ave.
Mountain View, CA
phone: (650) 969-0510

Please let me know when this info is no longer accurate, so I can remove it.

Keypad layout. Of course, this is not at all exciting if you already own one...

Hey! E&L Instruments is still alive, and on the web! Here's the URL: http://www.elinstruments.com/

Sample programs!
The beginning of a short discussion about the MMD-1. (Not the same thing, I know, but related.)
Assembly listing of the ROM from the MMD-1. Also the beginning of another thread about the MMD-1 and 8080.

Memory map:

4K RAM addresses $0000..$0FFF
ROM addresses $D800..$E7FF
256 bytes of RAM, ($FC00..$FCFF?)

DIP switches:

WE 0 - Write enable for addresses $0000..$03FF
WE 1 - Write enable for addresses $0400..$07FF
WE 2 - Write enable for addresses $0800..$0BFF
WE 3 - Write enable for addresses $0C00..$0FFF
SPARE - ???
HEX OCT - choose display and entry to be in Hexadecimal or Octal
PUP RESET - ???
EXEC USER - update binary LED's with data entry? Or not?
(in either setting, outputs to ports 0,1,2 still show)

Operation:

Enter bytes on the keypad of hex digits
Set MSByte of address by entering it on the keypad & pressing "HIGH".
... LSByte ... "LOW"
Change contents of memory at the selected address by entering the new value & pressing "STORE".
Look at adjacent memory locations with "NEXT" and "PREV".
Execute the program at the selected address by pressing "GO".

AUX functions:

BRL HI # - OFF disables BRL LO
BRL LO #
STEP #
SRC HI # - source for COPY/DUMP - OFF disables "DUMP" function
DES HI # - destination for COPY/DUMP
LEN HI # - length for COPY/DUMP
CLR TST ON - test if PROM is empty
POP PRM ON - program a PROM
DUP TST ON - test if PROM duplicated okay
PROM 2708/2716
MEM MAP RAM/ROM
BAUD 110/150/300/600/1200

Back to my classic computer web page
22-Apr-99

yakowenk@csx.unxc.edu

(remove all "x"s to get a valid address)