PROMAX MI-650 Trainer – Retro Computing

A Spanish firm developed a 6502 trainer, an SBC inspired by the KIM-1. Hexadecimal keyboard, 6 LED displays, I/O to experiment with. Assembled system, boxed, high quality components like mechanical keys. Aimed at education.

On this page:

Introduction to Promax MI-650
Manuals
Monitor EPROM images and sources
Images of MI-650
Images of MI-650B
Images of MI-650C
MI-650 video demonstrations

Three versions were made:

MI-650. 6502, 6532 for keyboard/LEDs/audio cassette, 6522 for user I/O, 2×2716 EPROM, 2x2K SRAM. PCB fingers edge connectors for expansion.
MI-650B. equal to the MI-650, more convenient expansion connectors.
MI-650C, a redesign, same dimensions and layout, with more modern components, like 65C02 CPU, larger EPROM and 65C22 for keyboard and LED.

All three share the same monitor program, patched for the MI-650C to use the 6522.

Statement by Promax about the 1979 Educational trainers
Educational instruments division was the result of our close commercial relationships with universities and technical schools. Work here was closely tied to the study plans of universities and technical schools in order to provide the educational material required by a variety of disciplines. Design work was begun on the MI-650B Microprocessor Trainer, based on the 6502 which appeared in 1975.

Updates from various sources, motivated by the find of Jose Vicente Marques Vidal of four MI-650s and our attempt to make them operational again (missing EPROMS mostly).

Manuals

	PROMAX MI 650 μ-instructor
	PROMAX MI-650-C Microinstructor (contains ROM listing and more)
	Microprocesadores de 8 bits 6502 promax MI-650C microinstructor

Monitor EPROM images and source

EPROM images are supplied by John Evans (in the KIM-1 Facebook group) and Youtube user @eeep73 and Dominic Bumbaca.
Identical dumps from two different MI-650s, so good dumps!
Archive with Promax MI-650 EPROM images (2x 2716 EPROMs).

Photo by Dominic Bumbaca

The MI650C manual has a listing of the monitor. This has been used to reconstruct the source of the MI-650 and the MI-650C monitor.
The resulting binary of the MI-650 monitor is checked against the ROM dumps and they are identical.
The source of the MI-650C is for most of the code identical to the MI-650 source. What is different is the IC used for the keyboard, LED displays, audio cassette control. The MI-650C has replaced the 6532 for a 65C22.
The source code is converted to more standard MOS Technology syntax, the original Spanish comments are retained.

Archive with Promax MI-650 monitor source
Archive with Promax MI-650C monitor source