Hello,

Apple II has a small resolution (256x192 pixels). It don't use
6845 (at that time this chip was too expensive !). I remember
that a phase method produces color on a PAL televisor. I have
experimented this on a Tensai portable TV.
I have somewhere the schematics but you could certainly
find them faster on a WEB Apple II site.

With a Triscend E5 chip, on a Xess card MySoc :

http://www.xess.com/

implementation of video is build in, with a VGA monitor port (170 $).
If you want video AND a 8051, this is the simplest method.

Best regards.