The internal DAC in most of these microcontrollers is way too slow for VGA. According to this[1], for STM32 you can generally expect at most 1MHz without extern

The internal DAC in most of these microcontrollers is way too slow for VGA. According to this[1], for STM32 you can generally expect at most 1MHz without external additions; that's way too slow even for e.g. 320x240 which has a pixel clock of over 10MHz. A lot of hobbyist projects use simple improvised DACs made with a few resistors. Here are mine for the ESP32[2] and the RP2040[3] (Raspberry Pi Pico), both use 320x240 (just the standard 640x480 with half the pixel clock and every line repeated to half the resolution in both width and height). [1] https://www.st.com/resource/en/application_note/an4566-how-to-extend-the-dac-performance-on-stm32-mcus-stmicroelectronics.pdf https://www.st.com/resource/en/application_note/an4566-how-t... [2] https://github.com/moefh/esp32-loser https://github.com/moefh/esp32-loser [3] https://github.com/moefh/pico-loser https://github.com/moefh/pico-loser