ESP32/components/u8g2/sys/avr/avr-libc

This directory contains code that can be shared across all AVR uC, when developing with https://www.nongnu.org/avr-libc/.

Please refer to https://github.com/olikraus/u8g2/wiki/Porting-to-new-MCU-platform to understand what is here.

At lib/u8x8_avr.h, you can find:

u8x8_byte_avr_hw_spi
Implements HW SPI communication. To use it, you're required to define SCK and MOSI ports externally (see example Makefiles).
u8x8_avr_delay
Implements the delay functions that are required by the GPIO and Delay callback function.

This means, you have to write little code to support your own project.

Please refer to the existing main.c and Makefile examples for details on how to use it.

Note: The code https://github.com/olikraus/u8g2/blob/master/sys/avr/avr-libc/lib/u8x8_avr.c requires
* `AVR_USE_HW_I2C` and/or
* `AVR_USE_HW_SPI`
to be defined in your IDE or Makefile.