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

[Darren A.]

>From: Roger Taylor
>
>Darren,
>
>Your 57600 example states "THERE ARE ROUGHLY 15.45 CYCLES PER-BIT (889980 / 
>57600)"
>
>The orginal 38400 bps COMM example states "894886.2 clock cycles per second 
>/ 38400 bits per second."
>
>In my 57600/115200 code, I used the 894886.2/57600 formula and came up with 
>~15.54 cycles per bit.  I based all of my precise timing on this and it 
>works without error as well.
>
>Anyway, since there's a ~.0851 cycle difference per bit, I guess it doesn't 
>matter for 1-8-1 (10) bits.  I'm just wondering which forumla is more 
>precise.  Sock Master, where are ya?
>
-

Roger,

After doing a little googling, I think its pretty likely that 894886.25 is 
the correct value. That is exactly one fourth the NTSC colorburst frequency 
of 3,579,545 Hz. I don't remember where I got that other value.

Reference: <http://en.wikipedia.org/wiki/Color_burst>

I will adjust my calculations and see if it affects any of the cycle counts 
I used.

Darren

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