[Coco] Source code for High Speed Bit-Banger I/O

[Darren A.]

>From: Roger Taylor
>
>At 02:25 PM 4/26/2007, you wrote:
>>For anyone who may be interested, I have posted my source code for doing 
>>57600/115.2K baud serial I/O through the CoCo bit-banger port. The file 
>>"SERBB56K.ASM" can be found in my upload space on CoCo3.com:
>>
>>http://www.coco3.com/users/DarrenA
>>
>>I know others have discussed this before, but I have never found any 
>>source code showing how to actually do it. I figured I would take a stab 
>>at it myself and thiis is the result. Feel free to use it in any way you 
>>please.
>
>
>Darren, your source code appears to be a modified version of the old comm5 
>source code posted online complete with the tutorial and CPU timing 
>comments.
>
>In my tests (you did test the code?) I discovered that there were more 
>tricks needed to achieve 115200 bps when connecting to a PC.
>
-
Yes Roger, my code was inspired by the COMM6 (38400 baud) source code posted 
online. Thats where I got the idea for doing the interleaved timeout. I also 
borrowed his comment style for showing the cycle counts, and the early/late 
info.

The speed increase, interleaved checksum, framing error detection, variable 
request count and termination due to a pause in the transmission were all my 
own enhancements.

I tested both the 57600 and the 115.2K operation on a CoCo 3 connected to my 
PowerMac G4 through a KeySpan High-Speed Serial adapter and the serial cable 
I bought from you. All my tests worked flawlessly (I have transferred whole 
disk images both ways without any data corruption).

Darren

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