Motorola 68K computer

Agfa ADC 5155 Motorola 68K Computer Teardown (Part 2 of 4)

This is the reverse engineering and teardown of a very interesting computer that runs on VME framework developed for the Motorola 68000 series CPUs. It runs a custom operating system called Monitor 4.28 developed by Agfa-Gevaert NV, Belgium.

I reverse engineered the “operating system” without any prior knowledge of how it worked. Throwing random commands at it I at some point discovered the “HE” command. This would show a full menu of commands that it would accept at the serial service port at the front of the computer.

If you missed Part 1, read it here: https://kaizerpowerelectronics.dk/teardown/agfa-adc-5155-x-ray-scanner-teardown-part-1-of-4/

List of AGFA Monitor 4.28 commands

  • ATX = Execute ASTRX shell command
  • BF = Block fill
  • BI = Block initialize
  • BM = Block move
  • BS = Block search
  • BT = Block test
  • BR = Breakpoints (BR -* clear)
  • BRS = Set Breakpoints cmd string
  • BO = Boot from disk
  • CPU = Set CPU parameters
  • CWS = Show Clock and Wait states
  • DA = Display or set DATE
  • DCP = Disk copy from 10 to 00
  • DI = Disassembler
  • DOS = Enter DOS mode
  • DU = Dump sector from disk
  • GO = Go target
  • GN = Go target, break at next instr
  • GT = Go target, set temporary break
  • HE = Help
  • fep = Show FEP info
  • IOP = IO disk read and write
  • IOT = IO teach
  • JSR = Jub to subroutine
  • LO = Load S-records
  • LOG = Show OS RAM logging
  • MAP = Select memory map
  • MD = Memory display
  • ML = Memory display link (range) == address1,address2 or address:count
  • MM = Memory modify
  • MS = Memory set
  • NAM = Show symbolic name
  • PF = Set Port format
  • PRJ = Select project
  • RAM = RAM test
  • RD = Register display
  • RDF = Display floating point regs
  • RDM = Display MMU regs
  • RES = Reset
  • SC = Set Control options
  • ST = Start clock
  • -swi = Switch CPU
  • T = Trace next (step into JSR)
  • TR = Trace next (skip over JSR)
  • TC = Trace on change of flow
  • TM = Transparent mode
  • TI = Display & Set clock time
  • TE = Switch to TEST menu
  • US = Start user program
  • VE = Verify S-records
  • VEC = Show vectors
  • VIC = Show VIC & hardware
  • VME = VME remote control
  • VIX = Boot from disk
  • X = Execute external shell command
  • XT = File transfer protocol

Mads Barnkob

Electrician, programmer, experimenter and amateur scientist with experience in industry automation, programming and all kinds of high voltage generating electronics. Administrator of https://kaizerpowerelectronics.dk and the high voltage community forum https://highvoltageforum.net

View all posts by Mads Barnkob →

4 thoughts on “Agfa ADC 5155 Motorola 68K Computer Teardown (Part 2 of 4)

Leave a Reply

Your email address will not be published. Required fields are marked *