16 Jul
2001
16 Jul
'01
1:32 p.m.
I hadn't
realized that on a PC w/ CGA that the light pen was getting
help from the CRT controller. That explains how a relatively simple
Yes. On most machines designed to have light pens, the CRT controller
does some of the work. The popular 6845, as I mentioned, has a lightpen
input pin. Incidentally, both the BBC Micro and the Sirius/Victor9000