Hello,
I configure my DMA in Normal mode. Here is my code:
void DMA1_Channel3_IRQHandler(void){ // USART3_RX
unsigned char CheckSum[2];
Var1=Var1+1;
if(Var1>1000){Var1=0;}
if(Buffer[0]==89 && Buffer[26]=='\n')
{
Var2=Var2+1;
if(Var2>1000){Var2=0;}
}
DMA_ClearITPendingBit(DMA1_IT_TC3);
DMA_ClearITPendingBit(DMA1_IT_TE3);
DMA_Cmd(DMA1_Channel3, DISABLE);
DMA_SetCurrDataCounter(DMA1_Channel3,sizeof(Buffer));
}
void EXTI9_5_IRQHandler(void){
if (EXTI_GetITStatus(EXTI_Line5) != RESET)
{
if(GPIO_ReadInputDataBit(GPIOA,GetPosition)==0 )
{
DMA_SetCurrDataCounter(DMA1_Channel3,sizeof(Buffer));
DMA_ClearITPendingBit(DMA1_IT_TC3);
DMA_ITConfig(DMA1_Channel3,DMA_IT_TE, ENABLE);
USART_ITConfig(USART3, USART_IT_ERR, ENABLE);
USART_DMACmd(USART3, USART_DMAReq_Rx, ENABLE);
DMA_Cmd(DMA1_Channel3, ENABLE);
GPIO_ResetBits(GPIOA,SendSignalPosition);
}
else
{
GPIO_SetBits(GPIOA,SendSignalPosition);
DMA_Cmd(DMA1_Channel3, DISABLE);
}
EXTI_ClearITPendingBit(EXTI_Line5);
}
}
Before each transmission, The transmitter change the PA.5 to low level , and if the receiver changes its SendSignalPosition pin(start DMA), the transmitter start transmitting and wait for 50us after all bytes being transferred.
This code works fine until I send some packages to the transmitter with DMA(TX) from the receiver. After sending some packages, the DMA looses the input sequence. I checked the variable Var1 and Var2 and I found out that Var1 is increasing ( the DMA is collecting the input bytes) but Var2 doesn't change after losing the input string sequence.
I need to know why this is happening while before each transsmison I disable/enable the DMA.
In addition, I've checked the Buffer[0] and I've seen that it contains the last character of the previous string. It seems the last character maintain in the buffer while the DMA is disabled.
