# Soft I2C For STM32 using HAL That is Edited version of [Original version](https://schkorea.tistory.com/437) for stm32 **usage:** define GPIO in `i2c_sw.h`: ```c #define GPIO_SW_I2C1_SCL GPIOB #define GPIO_SW_I2C1_SDA GPIOB #define GPIO_SW_I2C1_SCL_PIN GPIO_PIN_13 #define GPIO_SW_I2C1_SDA_PIN GPIO_PIN_14 ``` That example is for `stm32f103` , for use other micro replace `#include "stm32f1xx_hal_gpio.h"` in `i2c_sw.h`. This library has the ability to activate more than 10 software I2C , which have been commented in this library, but by default only one of them has been activated. **Example:** ```c #include "i2c_sw.h" int main() { SW_I2C_initial(); i2c_port_initial(SW_I2C1); while(1) { //Write DATA to Reg at Reg_Addr from I2C_Add Device connected to SW_I2C1 SW_I2C_WriteControl_8Bit(SW_I2C1,I2C_Add,Reg_Addr,DATA); //Read DATA at Reg_Add from I2C_Add Device connected to SW_I2C1 DATA=SW_I2C_ReadControl_8Bit(SW_I2C1,I2C_Add,Reg_Add); } } ```