- Joined Mar 12, 2011
I'm attempting to make a VGA controller and I want to improve upon my original shotty attempt at it. At this point I use two 555 timers to run hsync and vsync. Both have about 95% duty cycle. For my pixel clock I just loop in my pic program and toggle one of GPIO ports and that gives me about 100Khz. The display of color seems to be crawling up the screen and I believe it has something to do with my pixel clock speed. I'm quite excited that I have got this far in just displaying color but I want to improve upon it. Ultimately I need to calibrate the internal oscillation of my PIC. I have looked at designs online and they encompass using a 20-27MHz crystal connected to OSCCAL 1 and 2 to calibrate the PIC. I don't really understand how to setup my OSCCAL pins for correct calibration though, any suggestions? I know I want my osccal register to be set to HS so I can attain high frequency.