[Coco] Simple, reliable routines for the bitbanger serial port?

[Darren A]

On 3/16/09, Mike Pepe wrote:
> John,
>
> Just for completeness sake- I'm not aware of interrupt driven bitbanger
> stuff. I suppose it's possible on a CoCo3 using the timer interrupt, but
> due to the variable latency involved in servicing interrupts I think it
> would be a pretty poor method to drive the bitbanger.
>

The CoCo 3 can also generate an interrupt on a transition of the bit
banger's data input line.  I've never tried using it since,as you say,
the latency involved would make it very dificult to achieve a decent
level of performance.

The CoCo 3 schematic makes it look as though this interrupt would be
triggered on a low-to-high transition of the data line, but that would
make it pretty useless since a serial start bit is seen as a
high-to-low transition.

Darren