SHOWALL FUN PRANKS HIGH VOLTAGE LAZARUS-64 PHOTOGRAPHY SPY GADGETS VIDEO GAME
Figure 6 - The basic real-time VGA generator schematic
Figure 6 - The basic real-time VGA generator schematic

The Schematic shows how the microcontroller will be able to send the RRGGBBII color data to the RGB lines on the VGA connecter by first feeding it to the resistor DAC. The horizontal and vertical sync signals are fed to the monitor directly from the IO pins. The clock is a 20MHz oscillator module, but you will be fine with a 20MHz crystal as well. Actually, any speed would work, but you will have to do many changes to the source codes presented here as they are based on 20MHz, and every single cycle has to be accounted for during the video rendering interrupt.



Figure 7 - Connecting the port pins to the color palette DAC
Figure 7 - Connecting the port pins to the color palette DAC

I like to use wire colors that actually mean something, so the connection between the DAC as well as the VGA port have red, green, blue, and brown wiring to show the various colors and signals. All of my breadboard wiring is cut from CAT-5 wiring, as there are four colors, and the solid copper is perfect for breadboarding. Also, don't forget to run the ground wire from the VGA port to your breadboard circuit, or the monitor will fail to lock onto the signal.

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