Posted on September 20, 2017 at 11:18Hello,
I'm having trouble using I2C (Fast Mode, Master Mode) on a STM32F411RE (Nucleo-F411RE).
My code gets stuck after sending the I2C Address here:
while (!(I2C1->SR1 & I2C_SR1_ADDR));
On the bus I get short pulses, but no clock signal or data on SDA.
My full code is this:
//I2C configuration
void I2C_Config(void)
{
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN; //enable AHB1 GPIO->B clock
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; //enable Clock for I2C
GPIOB->AFR[1] |= (1 << 2) | (1 << 6); //AF4
GPIOB->MODER |= GPIO_MODER_MODER8_1 | GPIO_MODER_MODER9_1; //set PB8 & PB9 to alternate function
GPIOB->OTYPER |= GPIO_OTYPER_OT_8 | GPIO_OTYPER_OT_9; //Open-Drain configuration for PB8 & PB9, Reset configuration
///GPIOB->PUPDR |= GPIO_PUPDR_PUPDR8_0 | GPIO_PUPDR_PUPDR9_0; //External Pull-up's
GPIOB->OSPEEDR &= ~(GPIO_OSPEEDER_OSPEEDR8_0 & GPIO_OSPEEDER_OSPEEDR9_0);
I2C1->CR1 |= I2C_CR1_SWRST;
I2C1->CR1 &= ~(I2C_CR1_SWRST);
I2C1->CR2 &= ~(I2C_CR2_FREQ); //reset Frequency
I2C1->CR2 |= 30; //30MHz from APB1
I2C1->CCR &= ~I2C_CCR_CCR;
I2C1->CCR |= I2C_CCR_FS | I2C_CCR_DUTY | 3;
I2C1->TRISE |= 1 << 1 | 1 << 3;
I2C1->CR1 |= I2C_CR1_PE | I2C_CR1_ACK;
}
//Start I2C Communication
void I2C_Start(void)
{
I2C1->CR1 |= I2C_CR1_START;
while (!(I2C1->SR1 & I2C_SR1_SB));
}
//Stop I2C Communication
void I2C_Stop(void)
{
I2C1->CR1 |= I2C_CR1_STOP;
}
//Send I2C Slave Address
void I2C_ADDR(unsigned char ADDR)
{
char clear_addr_flag;
I2C1->DR = ADDR; //Write I2C Slave Address
while (!(I2C1->SR1 & I2C_SR1_ADDR)); //Wait till Address is sent
clear_addr_flag = (I2C1->SR2); //Reset ADDR-Flag
}
//Write Data (Byte) to I2C Bus
void I2C_Write(unsigned char write_data)
{
I2C1->DR = write_data;
while (!(I2C1->SR1 & I2C_SR1_TXE));
}
//Read Data from I2C Bus, Acknoledge Bit=> I2C_ACKD
unsigned char I2C_Read(void)
{
while (!(I2C1->SR1 & I2C_SR1_RXNE));
return (I2C1->DR);
}
Can someone tell me why the ADDR Bit is not set?
Thank you
#i2c #nucleo ##stm32f411re #stm32f4
