Thu Jun 4 19:11:56 CEST 2009

PIC CRT display controller

This requires the following elements:

  - High-priority ISR for jitter-free screen updates.

  - Background task for manipulating the frame buffer + communication.

The problem is that the shift register i'd like to use for
sprite/character drawing is also used for normal UART comm, so it
would be necessary to construct an SPI circuit.  This is an
interesting test case for building a distributed system, where
debugging console is daisy-chained.

Maybe use an 18F2620 for the video driver?  It has full 4k RAM and a
lot of ROM for characters and graphics.  It can be I2C/SPI slave and
drive the universal serial output as a synchronous master port at the
same time.

Maybe using a CAN interface will be better, since I'd like to build
such an interface for my car anyway.  With CAN, the device would have
to be an 18F2680.  It has the same EUSART and should be able to use
CAN in parallel.

Probably best to go for I2C first as it is quite a bit simpler.