Guru
Joined: 06/06/2011
Location: AustraliaPosts: 3369
| Posted: 11:22am 03 Mar 2012 |
Quote from the article in Silicon Chip:
The remarkable aspect of the video signal is that it is generated entirely in the PIC32 using nothing but the standard peripherals integrated inside the chip. The method used is based on a technique described by Lucio Di Jasio in his book "Programming 32 bit microcontrollers in C”. It uses a DMA (Direct Memory Access) controller to transfer the pixel data from memory to an SPI (Serial Peripheral Interface) controller which then clocks out the video with the required timing. The output is sharp and rock solid, you could not get better even if you were using a dedicated VGA controller.
Other than servicing an interrupt this method entirely bypasses the PIC32 CPU which only has to write the pixel data to a defined part of memory and it will then magically appear on the video monitor. This leaves the CPU free to run at full speed interpreting the user’s BASIC program.
Geoff Graham - http://geoffg.net