This has been discussed at length in this previous thread posted by you.

I still think you should get yourself an RS232 terminal. It is simple, quick, and easy to connect. You can be displaying your characters in a very short time. This solution can be also be accomplished using a PC as the terminal using software like HyperTerminal or ProComm.

Connecting the monochrome monitor can be done if you want to do all the work. But it will use up much time and many port pins on your microcontroller. The 6845 chip is a CRT controller that would work....but if you are thinking about production I would think twice about the fact that this is VERY old chip.

If your project is just to make one or two then it would be far simpler to connect an old surplus PC ISA bus monochrome adapter board to your microcontroller. That said however for 1 or 2 you would be FAR better off to locate a surplus RS232 terminal. And if your project was already using the serial port then pick a microcontroller that has 2 serial ports.

If you wanted to go through the exercise to build a CRT controller up from scratch just for the learning experience and can find a 6845 chip then by all means go for it!! If you use 6845 however you will also have to provide a character generator ROM, a display data memory, an oscillator, bunch of buffers, several multiplexers, and a double handful of discrete logic. Such design can be seen in the original IBM Technical Reference Manual for PC as Monochrome Display Adapter. It took 10 pages to show the whole schematic!!!

Michael Karas