Hi folks,
I've been programming Cortex-M0 chips for the past year in C, mainly STM32F0xx and SAMD21.
As part of learning how to use these microcontrollers, at first I like to skip using the HAL libraries provided by manufacturers and program registers directly. I often read the actual code of the manufacturer HAL libraries and compare it with the docs, before writing my own "simplified" version of these functions.
I've happily applied this approach to GPIO, ADC, Interrupts, CANbus, I2C, SPI, etc. But I haven't manage to extend it to USB, for example for USB CDC serial implementation. The manufacturer libraries are a mess of abstraction with layers of callbacks. The documentation is usually unclear.
Does anyone know of a simple example of USB code (preferably for CDC) for the STM32F0xx, SAMD21 or some relative? Something that a human can read?
Regards, Alain