Hello @SSaiy.1
First let me thank you for posting .
To interface with an I2C sensor using the STM32L412RB microcontroller in a bare metal (no operating system) environment, you will need to follow these steps:
- Configure the I2C peripheral:
- Enable the I2C clock in the RCC (Reset and Clock Control) register.
- Configure the I2C pins (SDA and SCL) as alternate function mode in the GPIO (General Purpose Input/Output) registers.
- Set up the I2C peripheral registers, including the control, status, and data registers, to configure the bus speed, addressing mode, and other parameters.
2.Initialize the I2C peripheral:
- Set the I2C mode to master or slave.
- Enable the I2C peripheral by setting the appropriate bit in the control register.
- Set the bus speed and addressing mode in the control register.
3. Communicate with the sensor:
- To read from the sensor, you will need to send a read command followed by the sensor's address. The sensor will then send back the requested data.
- To write to the sensor, you will need to send a write command followed by the sensor's address and the data to be written.
Here is some sample code that demonstrates how to configure and use the I2C peripheral to read data from a sensor:
#define I2Cx_CLOCK_SPEED 100000
// I2C peripheral configuration
void I2C_Init(void)
{
// Enable I2C clock
RCC->APB1ENR1 |= RCC_APB1ENR1_I2C1EN;
// Configure I2C pins as alternate function
GPIOB->MODER = (GPIOB->MODER & ~(GPIO_MODER_MODE8 | GPIO_MODER_MODE9)) | (GPIO_MODER_MODE8_1 | GPIO_MODER_MODE9_1);
GPIOB->AFR[0] = (GPIOB->AFR[0] & ~(GPIO_AFRL_AFSEL8 | GPIO_AFRL_AFSEL9)) | (1 << (8 * 4)) | (1 << (9 * 4));
// Configure I2C peripheral
I2C1->CR1 &= ~I2C_CR1_PE; // Disable I2C
I2C1->TIMINGR = (0x1 << I2C_TIMINGR_PRESC_Pos) | (0x13 << I2C_TIMINGR_SCLL_Pos) | (0xF << I2C_TIMINGR_SCLH_Pos) | (0x2 << I2C_TIMINGR_SDADEL_Pos) | (0x4 << I2C_TIMINGR_SCLDEL_Pos); // Configure bus speed and timings
I2C1->CR1 |= I2C_CR1_PE; // Enable I2C
}
// Read data from I2C sensor
uint8_t I2C_Read(uint8_t address, uint8_t reg)
{
uint8_t data;
// Send start condition
I2C1->CR2 = (I2C1->CR2 & ~I2C_CR2_SADD)
Thx
Ghofrane
