I2C problems - ADDR bit is not set

[salahuddinash]

Posted on May 24, 2014 at 11:45

Hi everyone, 

I'm trying to implement I2C1 on stm32f4-discovery to let the kit contact with a light-to-digital sensor TSL2581CS ..In the following code, the <b>I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)</b>returns ERROR although, BUSY, MSL, TxE and TRA are set and the AF bit is not set meaning that the address sent is acknowledged !!?? here's the whole code <b>#include <stm32f4xx.h>// this slave address belongs to the STM32F4-Discovery board's #define SLAVE_ADDRESS 0x39 // the slave address (example)void I2C1_init(void){ GPIO_InitTypeDef GPIO_InitStruct; I2C_InitTypeDef I2C_InitStruct; // enable APB1 peripheral clock for I2C1 RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE); // enable clock for SCL and SDA pins RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); /* setup SCL and SDA pins * You can connect the I2C1 functions to two different * pins: * 1. SCL on PB6 or PB8   * 2. SDA on PB7 or PB9 */ GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;   // we are going to use PB6 and PB9 GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;     // set pins to alternate function GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz; // set GPIO speed GPIO_InitStruct.GPIO_OType = GPIO_OType_OD; // set output to open drain --> the line has to be only pulled low, not driven high GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP; // enable pull up resistors GPIO_Init(GPIOB, &GPIO_InitStruct); // init GPIOB // Connect I2C1 pins to AF   GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1); // SCL GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1); // SDA // configure I2C1  I2C_InitStruct.I2C_ClockSpeed = 100000; // 100kHz I2C_InitStruct.I2C_Mode = I2C_Mode_I2C; // I2C mode I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2; // 50% duty cycle --> standard I2C_InitStruct.I2C_OwnAddress1 = 0x00; // own address, not relevant in master mode I2C_InitStruct.I2C_Ack = I2C_Ack_Disable; // disable acknowledge when reading (can be changed later on) I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit; // set address length to 7 bit addresses I2C_Init(I2C1, &I2C_InitStruct); // init I2C1 // enable I2C1 I2C_Cmd(I2C1, ENABLE);}/* This function issues a start condition and  * transmits the slave address + R/W bit *  * Parameters: * I2Cx --> the I2C peripheral e.g. I2C1 * address --> the 7 bit slave address * direction --> the transmission direction can be: * I2C_Direction_Tranmitter for Master transmitter mode * I2C_Direction_Receiver for Master receiver */void I2C_start(I2C_TypeDef* I2Cx, uint8_t address, uint8_t direction){ /* * EV5 : start bit sent (BUSY, MSL, SB) * EV6 : slave acknowledged address (BUSY, MSL, ADDR) * EV8 : DR ready for new byte to transmit, transmit buffer empty (BUSY, MSL, TxE) * EV9 : new byte received in the DR, receive buffer not empty (BUSY, MSL, RxNE)  */ // Wait until I2C1 is not busy any more ## Check flag BUSY = 0  while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));   // Send I2C1 START condition            ## Signal START on the bus  I2C_GenerateSTART(I2Cx, ENABLE); // Wait for I2C1 EV5(BUSY,MSL,SB)--> Slave has acknowledged start condition ## START correct while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT)); // Send slave Address for write  I2C_Send7bitAddress(I2Cx, address, direction); /* wait for I2Cx EV6 (BUSY, MSL, ADDR, TXE,TRA), check if  * either Slave has acknowledged Master transmitter or * Master receiver mode, depending on the transmission direction  ##Slave address acknowledged */  if(direction == I2C_Direction_Transmitter){ while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)); } else if(direction == I2C_Direction_Receiver){ while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)); }}/* This function transmits one byte to the slave device * Parameters: * I2Cx --> the I2C peripheral e.g. I2C1  * data --> the data byte to be transmitted */void I2C_write(I2C_TypeDef* I2Cx, uint8_t data){ // wait for I2C1 EV8 --> last byte is still being transmitted (last byte in SR, buffer empty), next byte can already be written while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTING)); I2C_SendData(I2Cx, data);}/* This function reads one byte from the slave device  * and acknowledges the byte (requests another byte) */uint8_t I2C_read_ack(I2C_TypeDef* I2Cx){ uint8_t data; // enable acknowledge of received data I2C_AcknowledgeConfig(I2Cx, ENABLE); // wait until one byte has been received while( !I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED) ); // read data from I2C data register and return data byte data = I2C_ReceiveData(I2Cx); return data;}/* This function reads one byte from the slave device * and doesn't acknowledge the received data  * after that a STOP condition is transmitted */uint8_t I2C_read_nack(I2C_TypeDef* I2Cx){ uint8_t data; // disable acknowledge of received data // nack also generates stop condition after last byte received // see reference manual for more info I2C_AcknowledgeConfig(I2Cx, DISABLE); I2C_GenerateSTOP(I2Cx, ENABLE); // wait until one byte has been received while( !I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED) ); // read data from I2C data register and return data byte data = I2C_ReceiveData(I2Cx); return data;}/* This function issues a stop condition and therefore * releases the bus */void I2C_stop(I2C_TypeDef* I2Cx){ // Send I2C1 STOP Condition after last byte has been transmitted I2C_GenerateSTOP(I2Cx, ENABLE); // wait for I2C1 EV8_2 --> byte has been transmitted while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));}int main(void){ uint8_t received_data; received_data += 0; I2C1_init(); // initialize I2C peripheral I2C_start(I2C1, SLAVE_ADDRESS<<1, I2C_Direction_Transmitter); // start a transmission in Master transmitter mode I2C_write(I2C1, 0x01); // write one byte to the slave I2C_stop(I2C1); // stop the transmission I2C_start(I2C1, SLAVE_ADDRESS<<1, I2C_Direction_Receiver); // start a transmission in Master receiver mode received_data = I2C_read_nack(I2C1); // read one byte and don't request another byte, stop transmission while(1);}</b>now what's the problem ??