Video controller IC for a CRT controller

General purpose display controller

This is a simple display controller. It can be controlled with a small microcontroller, such as MCS51, 68HC11, Z80, AVR and others.
Several years ago, I found an article that controlling a TV with only a PIC micorcontroller, and I surprised to it. It is very interesting to attempt to synthesize video signal with a micorcontroller.
However, it is not suitable for practical use because the microcontroller is occupied in synthesizing video signal, it cannot process any other operation. Therefore, this technic can be applied to a toy at the best.
It is required a display controller to contorl the video display, so I designed and built a simple display controller for RGB monitor and TV monitor.

Hardware

Several years ago, I built a display controller which is same with discrete parts. However, the CRTC (HD46505 or equivalents) used to the display controller has been discontinued, so that it cannot be obtained.
Recently, some CPLD family, such as Xilinx, Altera and Lattice, are polular in Japanese electronics enthusiasts, so that I also tried to use the Xilinx XC9500 family to learn it and to reduce wiring cost.

Features

At the first time, it determined specifications in consideration of the generality.
The host interface is compatible with SRAM to be connected to most microcontroler directly. It might be connected to the memory socket on the board. For microcontroller which doesn't export the data bus, it can also control it with I/O ports.
Video output format is RGB with composite sync. It will be directly connected to junk CRT/LCD monitors. However, the junk RGB monitor is not that easy to obtain, so it have to be also connected to a TV.
The resolution of 320 by 240 dots is sufficient for video monitors smaller than several ins and TV because their resolution is low. When higher resolution is used, video data should be processed will be much (i.e., it requires faster processor and more memory space). Similarly, number of colors is 16 because it is not for natural picture.
As above trems, the specifications for this display controller is determined as follows:

Composed with: Only ordinaly parts because this is for experimental use.
Host interface: SRAM compatible interface to connect most microcontroller easily.
Screen mode: Full graphic display without character generator to increase display flexibility.
Resolution: 320 by 240, 4bit/pixel.
Video outputs: RGB with composite sync, S-Video and C-Video (Encoding for last two is NTSC).

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AL0117 said:

6845 datasheets upped on MCU:
/ UsersFiles / AL / DataSheets

regards,Al

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