#FirmwareProgramming

[adafruit]

RP2040 USB host to program ESP chips through CDC chips

Historically, we've tested and programmed our Feather ESP8266 (https://www.adafruit.com/product/2821) and ESP32 boards (https://www.adafruit.com/product/3405) from a Raspberry Pi. We'd connect over USB and run esptool.py, which works fine but has more things that can go wrong: power flickering, SD card failures, etc. It's better to fully program it with a Pico RP2040 brain board. We can do that now because TinyUSB has support for USB CDC Serial chips (https://github.com/adafruit/Adafruit_TinyUSB_Arduino/tree/master/examples/DualRole/CDC/serial_host_bridge) like the FT232, CP210x, and WCH9102! We upload the stub and test firmware, then listen on the CDC for the self-test output. It works really fast and is much easier to manage.