[Coco] Bitbanger I/O routines?

Allen Huffman alsplace at pobox.com
Tue Feb 6 13:07:37 EST 2018

Rainbow published a program called REMOTE which would link input and ouput to the Serial I/O port. You could hook up a modem, then load and execute REMOTE, and all I/O to the screen went to the moment, and data from the modem was typed as if you were at the keyboard. These “remote terminal drivers” were used for BASIC BBSes.

In 1985, REMOTE2 was published, with modifications by someone else to do things more useful for BBSes - BREAK key disable, support for INKEY$, etc.

I printed out that listing and have been trying to figure out how it works. I know REMOTE got modified yet again with support for the RS232 pak, but I wondered if we know more today than we knew back then for doing this.

I’d like to come up with a very simple bitbanger I/O routine for a micro BBS in BASIC. I think hooking to output is pretty simple (there are some POKEs you can do then everything that PRINTs goes out the printer port, too). For input, I figured I could make a routine that would just expect X characters (or ENTER), and only look for input when called. I had a BBS that used this approach (not using LINE INPUT or INKEY$).

Does anyone have any bitbanger examples that might be useful for something like this?

How fast can the CoCo 1/2 go? I have seen 9600 baud on the CoCo 3 bitbanger in Twilight Term.

		— Allen

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