[vcf-midatlantic] Altair cant jump

Herb Johnson hjohnson at retrotechnology.info
Tue Jun 16 18:37:39 EDT 2020

Jeffrey Golas says, he's having problems running a UART echo program on 
his MITS Altair. He says he's doing this and that, entering this program 
and code and that, and getting results or not which he doesn't understand.

Well, Jeffrey Golas: you are doing the right sort of things! You are 
trying to understand the codes, and understand the hardware you have. 
You are testing one thing or another thing, and looking at results, and 
trying to decide "what's next? what works? what doesn't work?"

That is correct.

This is what one did with MITS Altairs in the era. They learned how to 
use them, at the binary level - like you are. They learned how the 
hardware worked, chip by chip, signal by signal. Why would that change 
NOW - if the hardware is the same, the software and front panel are the 

So: now that you have some experience and are at the limits of what you 
know: it's time to do some homework, to stretch your limits. Sorry, but 
this is actually the fun part. Re-read those MITS manuals now, and the 
Intel 8080 manual, and the UART manual. Learn more about how the 
front-panel works, and how the 8080 and the UART (whatever board it is) 
works. Try other UART programs, simpler ones.

Use some test equipment, to see the signals on the boards!

Then, toggle in more code. Check the wiring and settings on that UART 
board. Go where the symptoms lead you. This is the fun part!

And if this isn't fun, why the hell have an Altair around? That's your 
call of course, but you have my opinion on the matter. I think you are 
doing fine. Just keep doing it.

Regards, Herb Johnson

Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net
preserve, recover, restore 1970's computing
email: hjohnson AT retrotechnology DOT com
or try later herbjohnson AT retrotechnology DOT info

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