Monday, June 15, 2015

Martin Research Mike 2 Computer - vintage 1975

info click
An early addition to my computer collection was the Martin Research Mike 2 computer in December of 1979. Their are not many of these in existence & I am delighted to have the computer in our museum. Little information is available on the internet and what I found have links on this post.

Click photo to enlarge 
Bugbook Historical Microcomputer museum
Martin Research Mike 2 Computer 1975

The Mike 2 is a bare-bones system–just the CPU board with a 20-key keypad and a seven-digit displays. The customer supplied his own cabinet and power supply. The system was upgradeable to the faster 8080-based Mike 303A. The Mike series was for hobbyists looking for an inexpensive entry-level system.

Video of this computer "CLICK"

Donald P. Martin wrote the book "Microcomputer Design"  in 1976 (2nd edition) here is the whole  225 page PDF "CLICK"  

Bugbook Historical Microcomputer museum
CPU board 

CPU board uses the Intel  8008 Microprocessor.

Bugbook Historical Microcomputer museum
Memory Board 

The memory board uses 2112 RAM chips and 1702A EPROM Chips

Click on photos to enlarge 
Bugbook Historical Microcomputer museum
Interface connections 

The computer boards are connected together with a flat cable and the cable would connect to additional cards or equipment for interfacing.

1975 Purchase information from  Classic Tech
Martin Research Mike 203A (Mike 2)/Mike 303A (Mike 3) (1975, computer trainer)
Original Retail Price: $270 kit (Mike 2)/$395 kit, $495 assembled (Mike 3)
Base Configuration: 8008 (Mike 2)/8080 (Mike 3) CPU, up to 4K RAM, PROM storage, seven-digit LED, hex keypad, monitor software, operation manual
Important Options: I/O interface
Martin Research Mike 8 (1977, computer trainer)
Original Retail Price: $895
Base Configuration: Z80 CPU, 4K RAM, 1K ROM, LED readout, integral hex keypad, EROM programmer, power supply

Bugbook Historical Microcomputer museum

The Martin Research Mike 2 microcomputer had a number of  "First"

-- Used the first Intel 8 bit microprocessor 8008
-- Used the first Intel EPROM 1702A
-- Advertised in the first issue of Byte Magazine September 1975
-- Almost had the first single board microcomputer - instead they put the computer on 3 boards. Jon Titus is given credit in Wikipedia for the his MMD1 being the first microcomputer - see info "CLICK"

The Advertisement for Martin Research Mike 2 computer in Byte Magazine issues #1,2,&3 full page "CLICK"

Here are a few comment from Paul Roberson about Martin computers
I'm actually wondering if this is a Mike 2 - in the sense of the 'standard' version.

1) If you look at the board markings (which definitely are) they are very clearly labelled with (i) MR's address/other details and (ii) the product name (423A Mike 2-2) which is correct. The CPU board is labelled "401C" and is clearly a production run of some sort but it doesn't look to be the same set as the others.

2) The design of the board doesn't match the descriptions. One thing all the documents agree on is that the Mike 2 had the facility to save and restore all the registers. The problem is this is impossible on an 8008 without extra hardware - you need two external octal latches to store registers in while you manipulate them and you can't get round it with clever coding - this is because you can only access memory via HL. 

You also need latches to decode the bus at the various clock times. There one 3205 (3-8 decoder) - one of these is mandatory to decode timing information because of the 8008 package size, (this could be done using standard logic). Additionally, it has superfluous (and optional) I/O and the "Extra" pads which aren't connected to anything.

It could be a "Mike 1" which apparently existed (it's a simpler design), possibly a "Mike 4" which existed but wasn't released according to the MR book (the numbering and the clock circuitry are the same), or perhaps the process controller that is described in the Martin Research document (it has extensible I/O and no debugging) - as you say in the video, it looks like it was connected to *something*.

Or it could be that the adverts are fibbing about what the machine can do :)

The only other known pictures of Mike-2 machines are all top down shots where you can only see the console board.


Paul Robson
Bugbook Historical Microcomputer Museum
David Larsen
My Wife & I  had a wonderful time at the 18th birthday party for our granddaughters (twins) in Maryland and they also graduated on the same day - WOW great day May 6th 2015. Things have slowed some at our Chantilly Farm however still smaller events 13th a Wedding, 16th Virginia Crooked Road Show, and 20th a Prom Dance in the barn. I did have time to do a several video's and a blog this week. Still having fun at 76 yrs. 

           ."by David Larsen"  KK4WW Computer Collector Historian 

No comments:

Post a Comment

I look forward to your comments and will respond.