STM32F302R8 I2C1 Master Receiver. I2C_ISR_RXNE is not SET.

Question

Im using STM32F302R8 and developing the driver for I2CMasterReceive data from Arduino.

Here is my problem:

After I send a command code, from master 0x51, and generate the start condition, the RXNE is SET.

But, after it goes into the while loop, the RXNE suddenly RESET. I do not read yet the RXDR register.

I do not know why this problem happen. Could anyone help me?

Foued_KH · Answer

Hello @WM_IR ,

If only 1 BYTE needs to be Read, follow thus steps :

a) Write the slave Address, and wait for the ADDR bit (bit 1 in SR1) to be set. This indicates that the address has been transmitted

I2C1->DR = Address; // send the address
while (!(I2C1->SR1 & (1<<1))); // wait for ADDR bit to set

b) the Acknowledge disable is made during EV6 (before ADDR flag is cleared) and the STOP condition generation is made after EV6

I2C1->CR1 &= ~(1<<10); // clear the ACK bit 
uint8_t temp = I2C1->SR1 | I2C1->SR2; // read SR1 and SR2 to clear the ADDR bit.

c) Wait for the RXNE (Receive Buffer not Empty) bit to set

while (!(I2C1->SR1 & (1<<6))); // wait for RxNE to set

d) Read the data from the DR

buffer[1] = I2C1->DR; // Read the data from the DATA REGISTER

Foued

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