In a world where standards come and go with alarming speed, there’s something comforting about VGA. It’s the least common denominator of video standards, and seeing that chunky DB15 connector on the back of a computer means that no matter what, you’ll be able to get something from it, if you can just find a VGA cable in your junk bin.
But that’s the PC world; what about microcontrollers? Can you coax VGA video from them? Yes, you can, with an ESP32, a handful of resistors, and a little bit of clever programming. At least that’s what [bitluni] has managed to do in his continuing quest to push the ESP32 to output all the signals. For this project, [bitluni] needed to generate three separate signals – red, green, and blue – but with only two DACs on board, he had to try something else. He built external DACs the old way using R/2R voltage divider networks and addressed them with the I2S bus in LCD mode. He needed to make some compromises to fit the three color signals and the horizontal and vertical sync pulses into the 24 available bits, and there were a few false starts, but the video below shows that he was able to produce a 320×240 signal, and eventually goosed that up to a non-native 460×480.
It’s a pretty impressive hack, and we learned a lot about both the ESP32 and the VGA standard by watching the video. He’s previously used the ESP32 to build an AM radio station and to output composite PAL video, and even turned his oscilloscope into a vector display with it. They’re all great learning projects too.