This is a 8 bit GPU made entirely of TTL chips. It can convert any sequence of binary numbers to a composite video signal.

It consists of 10 8-bit comparators connected to the counter for keeping track of various signals. They are encoded with various gates like AND, NOR and OR

This is a 8 bit GPU made entirely of TTL chips. It can convert any sequence of binary numbers to a composite video signal. It consists of 10 8-bit comparators connected to the counter for keeping track of various signals. They are encoded with various gates like AND, NOR and OR.A typical video signal varies from 0V to 1V. The 0V is one horizontal/vertical sync pulse.

With the comparator constantly giving the signal on lines, screen and pulses, we can add a RAM and a MUX. The 8 bit output from RAM can be feeded to MUX which gives each bit one by one. We now have a waveform of bits.

Now, we need to make a digital to video converter. I have used a three state buffer to activate three different signals: 11 for white, 01 for black, 10, for gray. With the voltage divider and resistor ladder I stabilized the voltage to 0.3V for black, 0.7Volt for gray and 1V for white.

With an EPROM and a RAM, it is possible to draw (almost) anything on TV.

Check out the rough schematic. (I will add complete schematics and instructions soon!)

The schematic is missing all the logic gates and an oscillator.

Special thanks to Jack Eisenmann