GitHub - microchip-pic-avr-examples/pic16f15244-family-advanced-i2c-io- expander: This code example implements an advanced 8-bit I2C I/O expander using the general purpose PIC16F15244 family of parts (PIC16F15245, PIC16F15244, and PIC16F15243).
Arduino Interface PCA9555 GPIO Expander With Code
PCF8574 i2c digital I/O expander: Arduino, esp8266 and esp32, basic I/O and interrupt – Part 1 – Renzo Mischianti