epd42_library

Library extension from the work of Ben Krasnow (Applied Science).

This extension enables a more cautious use of Direct Updates, while preserving a reasonable contrast, and allows image gray shading (with 8 levels of gray shades).
It also enables the use of the ESP32 as a compatible board, but be careful if using the PSRAM or the SD card; the buses are shared...
To use the ESP32 board, in the file "epdif.h" comment out #define AVR_ARCH (which is default for Teensy boards). In that same file you will find the SPI pin definitions for both boards.

In the provided Arduino examples, you may find that you also need an additional library, called "Dither.h". Not to worry, you can download it from here (a previous repository).

See my website article on the subject for a more in-depth explanation of the theory behind the operation, or to see the results of my analysis.