Hi, Bob.

BL> FM> It's limited by the time to process the interrupt routine on
BL> FM> each tick. I *think* you should be able to get it down quite
BL> FM> low on your machine, certainly less than 10, maybe 2-5. Maybe 1
BL> FM> on mine. I'd be interested to know how low you can go.

BL>  Nothing happens once you get below 200 or so. The pulse just stays
BL>50uS wide.

Then that's the limit of the machine's ability to do all the
instructions in the interrupt service routine before another interrupt
comes along. Which surprises me.

BL> FM> Yeah, the // port should be able to get over 100kHz on your
BL> FM> machine, IMHO.

BL>  ROFL! For 8 bits = 400uS = 2,500Hz. The pulse width is 50us = 19200
BL>baud. It's a low way short of 100KHz and 200,000 Baud.

Sure, if that's the limit. A back-of-an-envelope suggested it should be
much faster. There's only about 30 instructions in there (if it doesn't
have to call the old timer tick routine, once every 55mS. Wish I had a
bloody CRO.

Regards, FIM.

 * * Modeming is an exercise of bits, bytes and bauds
@EOT:

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