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stm32f4 ,i2c bug when acknowledge enabled

Question asked by ali.med on May 14, 2015
I am reading data from a ds 1621 on stm32f4 using i2c 1 on pb6 and pb7.
Data sent by the device  is fragmented into 2 bytes according to datasheet.I tried to read the first byte.It worked great.Then i decided to add the second byte to my code which in ordrer to be read must be sent after an acknowledge request from the master (stm32f4).so i enabled the acknowledge request as indicated in the code.But since i did that the device can't handle start bit requests and the I2C_EVENT_MASTER_MODE_SELECT flag is never raised.
Any suggestions please? 
#include "stm32f4xx.h"
#include "stm32f4xx_i2c.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"
#include "misc.h"
int main(void)
{int data=0;
int data2=0;
GPIO_InitTypeDef GPIO_InitStructure;
I2C_InitTypeDef  I2C_InitStructure;
 
/* Enable the I2C periph and GPIOB */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
 
GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);
 
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7;
GPIO_Init(GPIOB, &GPIO_InitStructure);
 
I2C_InitStructure.I2C_Ack=I2C_Ack_Disable;
//I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_OwnAddress1 =144;
I2C_InitStructure.I2C_AcknowledgedAddress=I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_ClockSpeed=20000 ;
I2C_InitStructure.I2C_DutyCycle=I2C_DutyCycle_2;
I2C_InitStructure.I2C_Mode=I2C_Mode_I2C;
 
I2C_Init(I2C1, &I2C_InitStructure);
I2C_AcknowledgeConfig(I2C1,DISABLE);
I2C_Cmd(I2C1,ENABLE);
while(1)
{
I2C_GenerateSTART(I2C1, ENABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
I2C_Send7bitAddress( I2C1,144,I2C_Direction_Transmitter);
while( !I2C_CheckEvent(I2C1,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
I2C_SendData(I2C1,0xEE);//start conversion
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
I2C_GenerateSTOP(I2C1, ENABLE);
 
I2C_GenerateSTART(I2C1, ENABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
I2C_Send7bitAddress(I2C1, 144,  I2C_Direction_Transmitter);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
I2C_SendData(I2C1, 0xAA);//read temperature
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
 
I2C_GenerateSTART(I2C1, ENABLE);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
        I2C_Send7bitAddress( I2C1,144,I2C_Direction_Receiver);
    while( !I2C_CheckEvent(I2C1,I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
    I2C_AcknowledgeConfig(I2C1,ENABLE); //    Line A
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    data=I2C_ReceiveData(I2C1);
    I2C_AcknowledgeConfig(I2C1,DISABLE);//B
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));//when i add line A ,B  C and this line  I2C_EVENT_MASTER_MODE_SELECT never happens
    data2=I2C_ReceiveData(I2C1);//C
    I2C_GenerateSTOP(I2C1, ENABLE);
    I2C_GenerateSTART(I2C1, ENABLE);
       while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress( I2C1,144,I2C_Direction_Transmitter);
while( !I2C_CheckEvent(I2C1,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
I2C_SendData(I2C1,0x22);
while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
I2C_GenerateSTOP(I2C1, ENABLE);
}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
}

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