Library 09- I2C for STM32F4
I2C or Inter-Integrated Circuit is a multimaster serial single ended bus. This protocol is commonly used with RTC modules, temperature sensors, EEPROMs, IO expanders and more. I2C protocol uses 2 wires: SCL: Serial Clock, clock for serial synchronization SDA: Serial data, bidirection line for receving and transmitting Both wires need external pull up resistor, from about 4k7 to 47k, if you don’t use pull up resistors in MCU. In our case, you don’t need external pull ups, because library uses internal in STM32F4.