[Coco] Run of RGB2VGA boards

[Barry Nelson]

The official Tandy service manual says (which I just looked at) says…

PIA IC4
FF22
BIT 3 = RGB Monitor sensing input   CSS

But if the CM8 dis not ground the pin or otherwise apply a signal to it, and BASIC sets the pin as an output then it sounds like something that the engineers added to the hardware but was never used in software. Interesting… It also doesn't sound like much of anything can support it if BASIC sets it as an output. I don't remember seeing any code in OS9 drivers that read that pin either. 

On Sep 12, 2015, at 10:52 AM, Brett Gordon <beretta42 at gmail.com> wrote:

> I always assumed it was a monitor detect.  I read two references via google:
> 
> 1. The CM8 didn't connect this pin to ground.
> 2. BASIC sets this PIA pin as an output...probably a goof. Of course, coco2 didnt have monitor anyway.