March 18, 2022

Callan Multibus 68k computer - using the Prom monitor

As I have noted elsewhere, once you remove the pair of "auxiliary" roms, the Callan will fire up the Prom monitor at 9600 baud on the main serial port.
A n - open address register (0-6)
B - set breakpoint
C addr - continue program
D n - open data register (0-7)
E addr - open 16 bit word at address
G addr - start program
I mode - set uart mode
K - soft reset
L cmd - send command to host (implicit I B
M map - open setment map register
O addr - open 8 bit byte at address
P page - open page map register
R - open misc registers
S s-record
X char - set char for transparent mode
The Uart mode stuff expects port B to be connected to a host computer. Think of it this way. The Callan served as a sort of "super terminal" in the day, with some big machine on port B. port A was connected internally in the Callan to a built in terminal. So transparent mode was a pass through from the Callan terminal on A to a host on B. Almost none of this is relevant today, at least for me with the Callan terminal long gone and forgotten.

Opening a location is to display it and allow you to modify it. If you don't want to, you hit return and you move on to the next location. I type a "." (period) to stop all this.

You can download S records by hand, but I wrote a python program to automate loading a batch of them and then running the downloaded program.


Feedback? Questions? Drop me a line!

Tom's Computer Info / [email protected]