A Minimum Interface to control processors #Forth #debug #Serial


Juergen Pintaske
 

https://pages.cs.wisc.edu/~bolo/shipyard/3ins4th.html?fbclid=IwAR22RxSqRTJhFqLn_tgCaRrFr1v64wR4Rv0ORwXsLO4husLDDXdOAMMqYdI
I just remebered this link.

OK it is Forth, but should be relevant for any processor - here 180x - or language.

How difficult would it be to adapt an existing 1802 monitor program ( with bit bang implemented already ) to the required functionality?


Lee Hart
 

Juergen Pintaske via groups.io wrote:
I just remembered this link.
OK it is Forth, but should be relevant for any processor - here 180x - or language.
How difficult would it be to adapt an existing 1802 monitor program ( with bit bang implemented already ) to the required functionality?
Hi Juergen,

Yes, it is an interesting idea! In a way, this is what any monitor program can do. The difference is that most monitors have more features than just read/write/run, because they are expected to be used by people rather than computers. He made this "monitor" as small as possible, by only operating it with a computer.

When you operate it with a computer, I suspect you could do it all with just *one* command; write-and-run. This is the method that the Fluke 9010 Troubleshooter used; it would load a tiny program to do whatever command you want to execute -- read memory, write memory, run a program, read or write to an I/O port, find or test RAM, checksum ROM, etc.

A bit-banger routine for the 1802 can be pretty small; 10-20 bytes. One could be written to read a string of characters, treat them as 8-bit binary, load them into memory, and then execute them. This should give the remote system the ability to do anything. It could load little programs to (for example) create a bit-bang serial output, read a block of memory, and send it back to the host system.

Lee Hart

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