See ​the bible by Gerry Kane (warning, large file!)

Here are some thoughts on the chips he describes:

DP8350 is fixed-timing (e.g. 24x80). Includes much of the dot timing. Provides full memory addressing logic and provision for a line buffer. National/TI have quite a bit of literature:

• ​http://www.bitsavers.org/components/national/_appNotes/AN-0243.pdf
• ​https://www.ti.com/litv/pdf/snoa611

8275 expects a CPU to fill line buffers. (used for ETC Idea or Vision)? Not memory-mapped.

6845 is basically a bunch of counters, providing character address, HS and VS and cursor control.

Can use as bit-map display by using character row as extra address bits. This would result in funny address mapping but could easily handle e.g. VGA resolution with 8 bit depth (300k pixels).

Idea: make a hybrid bit-map/character display. Send MA to two RAMs, one with character output, another with bitmap output. Use RAMDAC to combine character and bitmap data.