STM32L152 Discovery I2C problem with status register

[rdoljak]

Posted on July 11, 2014 at 10:53

Hello 

My problem is that i cannot communicate with the temperature sensor via I2C because the code stop working and the problem is in the status register but i dont know how to fix itcan anybody can help me ?this is the communication code:#include <stm32l1xx.h>#include <stm32l1xx_i2c.h>// this slave address belongs to the STM32F4-Discovery board's// CS43L22 Audio DAC// connect PD4 to VDD in order to get the DAC out of reset and test the I2C// interface#define SLAVE_ADDRESS 0x40 // the slave address 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_AHBPeriphClockCmd(RCC_AHBPeriph_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 PB7 GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF; // set pins to alternate function GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz; // 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){ // wait until I2C1 is not busy any more while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY)); // Send I2C1 START condition I2C_GenerateSTART(I2Cx, ENABLE); // wait for I2C1 EV5 --> Slave has acknowledged start condition while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT)); // Send slave Address for write I2C_Send7bitAddress(I2Cx, address, direction); /* wait for I2Cx EV6, check if * either Slave has acknowledged Master transmitter or * Master receiver mode, depending on the transmission * direction */ 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){ // 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 uint8_t 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){ // 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 uint8_t 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){ I2C1_init(); // initialize I2C peripheral uint8_t received_data; 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); return 0;