i2c_soft
I2C is a data transfer bus. Normally one master and one or more slaves are connected to the bus. The master addresses one slave at a time to transfer data between the devices.
This driver implements I2C in software for MCUs without I2C hardware support. For systems with hardware I2C support, the i2c driver will probably be preferable.
Source code: src/drivers/i2c_soft.h, src/drivers/i2c_soft.c
Test code: tst/drivers/i2c/master_soft/main.c
drivers/i2c_soft.h