vt100 terminfo with padding for an actual vt100?

Eric Christopherson echristopherson at gmail.com
Tue Sep 6 19:40:26 CDT 2016

On Tue, Sep 06, 2016, Cameron Kaiser wrote:
> > Interesting. I've been trying to get a WiFi device for the Commodore
> > 8-bits working consistently in 9600 bps mode, and have just been
> > assuming the garbage characters I get when I receive a screenful of text
> > all at once were due to buffer overruns. The garbage characters there
> > look like actual garbage, not like partial CSIs like [3;1m or whatever.
> Unless you're using an ACIA cartridge, 9600bps on the C128 is problematic,
> and impossible on the C64.

Not quite; someone named Daniel Dallmann found a way to do it on the
user port, on both 64 and 128 (in the 1990s, I think). It's commonly
called "UP9600". I've only found one terminal program* so far that
actually performs well and doesn't drop characters or bring up garbage
ones, on the device I mentioned (I have never tried it with a proper

I'm not sure what's different about the CIAs in the 64 and 128 but, in
the case of this specific hack, it's theoretically easier to deal with a
64 -- or at least a 128 with no 1571 or 1581 -- because the 9600bps hack
clobbers the SRQ line that those drives use for fast serial operations.
(Things still work if you turn them to slow mode, as happens when you
boot directly into 64 mode.) But I find that I never get it to work
non-problematically except when I use that one terminal emulator using
the C128's VDC for display. I'm not sure how much the 40-column mode's
1MHz clock contributes, and how much VIC emulated 80-column mode and the
VIC's scrolling speed, contribute to the problem. (Will have to try it
with true 40-column mode, but then the actual viewport will fill with
characters and need a scroll twice as fast.)

* The terminal emulator I've had success with is NovaTerm 9.6.

> If you *are* using an ACIA cartridge, then 9600bps is well within spec and
> should "just work." I'd look at your driver instead. A buffer overrun 
> should just drop characters, not munge them.

I wish I could get more than one-sentence responses from the developer
of the device. Hopefully he'll fix it in the future, if I can make a
good case for it.

> -- 
> ------------------------------------ personal: http://www.cameronkaiser.com/ --
>   Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com
> -- Burglar alarms: For the man who has everything! ----------------------------

        Eric Christopherson

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