Thanks for all the info Mike. The reason I want to use a CGA card is because it has a composite video output jack, so I can connect it to a TV directly. The processor I want to use is the (old) 8751H...because I already have a whole bunch of those that I got a no cost. Remember that this is for hobby use (home automation), so I try to use what I have already. I have already made two very successful 8751 projects so far and I really enjoy the designing and programming of these projects.

The goal of this project is to connect to the RS485 bus of my home automation system (I already have the protocol and one working project using it) and emulate a module that normally allows you to output ascii strings to a serial port, and create a TV display instead. I even plan on using simple "escape sequences" (maybe based on a VT52 terminal) to allow cursor positioning commands to be embedded in the ascii strings. This way I could have it display temperatures, events, etc. on a TV. As you pointed out, the i/o ports are mostly to set up the 6845 video controller chip and memory is directly mapped to the display RAM. I might even be able to use some of the extra memory to hold general data for my 8751 program. I'm sure glad the data and address bus are multiplexed on an 8 bit ISA card because I'd quickly run out of i/o pins if not. The routines to drive this will end up looking a lot like the ones to drive an LCD display. This should be fun.