[Coco] Drivewire with RS232 pak
gheskett at shentel.net
Mon Oct 29 07:24:54 EDT 2018
On Monday 29 October 2018 01:46:03 Andrew wrote:
> You mentioned something about DW being able to run at 200+ kbaud on
> the bitbanger with a new opamp? Got any more info on this? That is -
> what new opamp, where does it go (I presume somewhere inside the
> CoCo), etc?
I've heard story's of 230k Andrew, but I'd expect even the coco3's op-amp
isn't fast enough. Would probably need to be upgraded to at least an
LM357. I've not tried it personally. T.I. also has some single ended
op-amps that are in the $1.50 range that handle full amplitude ntsc
video. And do it faster than Grass Valley's version they wanted $1500
for when they started dying in our 300 3A/B video switcher at the tv
station. Their increased speed, caused faster propagation and a color
shift as the fader lever was used to change sources. They used 4 such
amps in each channel, so 24 of them would have brought it back into
time, but I never found the time to actually do it.
Theres only one op-amp in the coco's, in the bit banger circuitry.
> Andrew L. Ayers
> Glendale, Arizona
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