Posted on January 11, 2013 at 10:33Hello All,
I am programing an EEPROM which is interfaced to STM32 via I2c2. I am using DMA interrupt for reading data from EEPROM location. I feel Writing to EEPROM works fine and could see TxE and TRA flags set while trsanmitting the data from STM. But i have problem in redaing data from EEPROM. I can see no flags set when i watch the registers. The DMA interrupt occurs but DMA_FLAG_TCIF0 doesnt get clerared. Either I am able to see some data in the buffer.
I have posted the code.Please let me know where am I going wrong
void ReadBuffer(uint8_t* pBuffer, uint16_t ReadAddr, uint16_t* NumByteToRead)
{
uint16_t data;
uint8_t i;
ptEEDataReadPointer=NumByteToRead;
// While the bus is busy
Timeout=LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C2, I2C_FLAG_BUSY))
{
Timeout--;
if (Timeout==0)
{
return TIMEOUT_ERROR;
}
}
//Send START condition
I2C_GenerateSTART(I2C2,ENABLE);
//Test on EV5 and clear it (cleared by reading SR1 then writing to DR)
if(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT))
{
I2C_GenerateSTART(I2C2,ENABLE);
}
Timeout=FLAG_TIMEOUT;
while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT))
{
Timeout--;
if(Timeout == 0)
{
return TIMEOUT_ERROR;
}
}
I2C_Send7bitAddress(I2C2, nEEAddress, I2C_Direction_Transmitter);
//Test on EV6 and clear it
if(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
{
I2C_GenerateSTART(I2C2,ENABLE);
I2C_Send7bitAddress(I2C2, nEEAddress, I2C_Direction_Transmitter);
}
I2C_SendData(I2C2, ReadAddr);
//Test on EV8 and clear it
Timeout = FLAG_TIMEOUT;
data = I2C1->DR;
//Send STRAT condition a second time
I2C_GenerateSTART(I2C2, ENABLE);
//Test on EV5 and clear it (cleared by reading SR1 then writing to DR)
Timeout = FLAG_TIMEOUT;
while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT))
{
if((Timeout--) == 0)
return TIMEOUT_ERROR;
}
//Send EEPROM address for read
I2C_Send7bitAddress(I2C2, nEEAddress, I2C_Direction_Receiver);
/* If number of data to be read is 1, then DMA couldn't be used */
/* One Byte Master Reception procedure (POLLING) */
if ((uint16_t)(*NumByteToRead) < 2)
{
//Disable Acknowledgment
I2C_AcknowledgeConfig(I2C2, DISABLE);
//Clear ADDR register by reading SR1 then SR2 register (SR1 has already been read)
(void)I2Cx->SR2;
// Read the byte received from the EEPROM
*pBuffer = I2C_ReceiveData(I2Cx);
//Send STOP Condition
I2C_GenerateSTOP(I2Cx, ENABLE);
/*!< Decrement the read bytes counter */
(uint16_t)(*NumByteToRead)--;
/* Wait to make sure that STOP control bit has been cleared */
Timeout = FLAG_TIMEOUT;
while(I2Cx->CR1 & I2C_CR1_STOP)
{
if((Timeout--) == 0)
return TIMEOUT_ERROR;
}
Here is my Interrupt service routine
void DMA1_Stream3_IRQHandler(void)
{
//Check if the DMA transfer is complete
if(DMA_GetFlagStatus(DMA1_Stream3, DMA_FLAG_TCIF0) != RESET)
{
//Send STOP Condition
I2C_GenerateSTOP(I2Cx, ENABLE);
//Disable the DMA Rx Stream and Clear TC Flag */
DMA_Cmd(Stream3, DISABLE);
DMA_ClearFlag(Stream3, DMA_FLAG_TCIF0);
*ptEEDataReadPointer = 0;
}
Thanks
#i
