I2C problems

[tiche79]

Posted on March 26, 2014 at 16:10

Hi

I'm trying to write and read some data into a EEPROM (AT24MAC402) with my STM32F417 in I2C but the program loops in the START and don't write or read in the EEPROM. There is a status in ''stm32f4xx_i2c.c'' that stays in ERROR and never past in SUCCES.I think that the Salve Address is correct so I do not know where the problem may beThanks for your helpHere is my program:/** ****************************************************************************** * @file     Test_I2C/main.c * @author   DVC-Co * @version V1.0.1 * @date     04-February-2014 * @brief   Main program body ****************************************************************************** *//* Includes */#include ''stm32f4xx.h''#include ''stm32f4_discovery.h''#define SLAVE_ADDRESS 0xA0 /* Private variables */uint8_t received_data[2];uint8_t I2C_read_ack(I2C_TypeDef* I2Cx);uint8_t I2C_read_nack(I2C_TypeDef* I2Cx);/* Private function prototypes */void init_I2C1(void);void I2C_start(I2C_TypeDef* I2Cx, uint8_t address, uint8_t direction);void I2C_write(I2C_TypeDef* I2Cx, uint8_t data);void I2C_stop(I2C_TypeDef* I2Cx);/****===========================================================================****  Abstract: main program****===========================================================================*/int main(void){ init_I2C1(); // initialize I2C peripheral while(1) { I2C_start(I2C1, SLAVE_ADDRESS<<1, I2C_Direction_Transmitter); // start a transmission in Master transmitter mode I2C_write(I2C1, 0x20); // write one byte to the slave I2C_write(I2C1, 0x03); // write another 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[0] = I2C_read_ack(I2C1); // read one byte and request another byte received_data[1] = I2C_read_nack(I2C1); // read one byte and don't request another byte, stop transmission }}void init_I2C1(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 I2C1 to two different * pairs of pins: * 1. SCL on PB6 and SDA on PB7 * 2. SCL on PB8 and SDA on 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_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);}void I2C_start(I2C_TypeDef* I2Cx, uint8_t address, uint8_t direction){ //I2C_ClearFlag(I2Cx, I2C_FLAG_BUSY); // wait until I2C1 is not busy anymore 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 I2C1 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));

He stuck here

} 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){ I2C_SendData(I2Cx, data); // wait for I2C1 EV8_2 --> byte has been transmitted while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));}/* 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 recieved 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 recieved data */uint8_t I2C_read_nack(I2C_TypeDef* I2Cx){ // disabe 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 funtion issues a stop condition and therefore * releases the bus */void I2C_stop(I2C_TypeDef* I2Cx){ // Send I2C1 STOP Condition I2C_GenerateSTOP(I2Cx, ENABLE);}

[stm322399]

Posted on April 02, 2014 at 17:20

Oh, lucky you are, I just tumbled on the following:

static uint8_t I2C_read8(uint8_t regnum)
{
int maxloop = 1000000;
uint8_t value;
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Transmitter);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_TXE) == RESET ) if (!maxloop--) goto error;
I2C_SendData(I2C1, regnum);
I2C_AcknowledgeConfig(I2C1, DISABLE);
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Receiver);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET ) if (!maxloop--) goto error;
value = I2C_ReceiveData(I2C1);
I2C_GenerateSTOP(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) == SET ) if (!maxloop--) goto error;
return value;
error:
LOG_ERROR();
return 0;
}

Beware that this routine is a special case for reading a single byte only.

static uint16_t I2C_read16(uint8_t regnum)
{
int maxloop = 1000000;
uint8_t valueL, valueH;
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Transmitter);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_TXE) == RESET ) if (!maxloop--) goto error;
I2C_SendData(I2C1, regnum);
I2C_AcknowledgeConfig(I2C1, DISABLE);
I2C_GenerateSTART(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_SB) == RESET ) if (!maxloop--) goto error;
I2C_Send7bitAddress(I2C1, IOEXP_ADDR*2, I2C_Direction_Receiver);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR) == RESET ) if (!maxloop--) goto error;
I2C1->CR1 |= I2C_CR1_POS;
I2C_GetFlagStatus(I2C1, I2C_FLAG_MSL);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET ) if (!maxloop--) goto error;
valueL = I2C_ReceiveData(I2C1);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET ) if (!maxloop--) goto error;
valueH = I2C_ReceiveData(I2C1);
I2C_GenerateSTOP(I2C1, ENABLE);
while ( I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) == SET ) if (!maxloop--) goto error;
return valueL | (valueH<<8);
error:
LOG_ERROR();
return 0;
}

Reading 2 byte is again a special case. To read N>2 bytes, you just need to set ACK before the first reception, and clear ACK at the N-1 received byte (see previous post)