[Coco] RAM SIZE INPUT mystery (solved)

[Nickolas Marentes]

Thanks Chuck. That explanation as to what the RAM SIZE INPUT & OUTPUT 
pins are on the CoCo3 makes sense.

Holding down the F2 key simulates setting the RAM SIZE jumpers of the 
CoCo1/2 for 4K for old software that actually looks at this. I'm not 
aware of which programs needed this but for the sake of compatibility it 
has been included it would seem.

This adds to the other function available at Powerup of the CoCo3 which 
sets the color phase for NTSC composite video when the F1 key is held 
down. Again, this was for compatibility of CoCo 1/2 programs that used 
artifact colors allowing the use to set the correct color scheme (red & 
blue).


Chuck Youse wrote:

Two words: backwards compatibility. The designers of the Coco 3 bent
over backwards to maintain compatibility with the Coco/Coco 2 software
base, and that meant maintaining the PIA pin functions. Does it do
anything on the Coco 3? Nah, other than convincing Coco 2 programs that
they've got 64K to play with. Or something like that.