[Coco] CoCo 2 bitbanger does 57600 bps!

[Roger Taylor]

At 07:34 PM 3/23/2006, Boisy Pitre wrote:

>Another issue is that protocols like DriveWire are bi-directional;
>the CoCo sends a command, the PC receives it and sends a response.
>Some faster PCs would turn the response around so fast that the start
>bit would be missed by the CoCo.  If you're going to build
>reliability into your process you will need some method of passing a
>checksum or other signal back and forth.  That turn-around time
>steals cycles from your CoCo that could be used to look for the next
>start bit, so you may have to throttle the PC at those points.  Also,


It's true that at 57600 bps over the bitbanger port that a special protocol 
has to be used.  In my prototype I am using probably the most trickiest 
code I've used since some of the self-patching routines in Projector-3, but 
no patching is done in my bitbanger code.  It's just plain 6809 code that 
doesn't change.  No PC throttling is needed.  It can respond in a nano and 
the CoCo won't miss it.



Roger Taylor