2019-04-24 09:49 PM
Hello everyone, I am a beginner on STM32F4. I want to using DMA for receiving data via USART. But it doesnot work, please help me to solve the problem. Here is my code:
void USART2_ConfigDMA(void)
{
DMA_InitTypeDef DMA_InitStructure;
RCC->AHB1ENR = RCC_AHB1ENR_DMA1EN;
DMA_InitStructure.DMA_BufferSize = 10;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable ;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_1QuarterFull ;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single ;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_PeripheralBaseAddr =(uint32_t) (&(USART2->DR)) ;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_Channel = DMA_Channel_4 ;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory ;
DMA_InitStructure.DMA_Memory0BaseAddr =(uint32_t)&data[0];
DMA_Init(DMA1_Stream5,&DMA_InitStructure);
USART_Cmd(USART2, ENABLE);
USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);
DMA_Cmd(DMA1_Stream5, ENABLE);
}
Thanks for your support !
Solved! Go to Solution.
2019-04-24 10:29 PM
Probably want to start by ORing clock enable bits, rather than blind writing..
RCC->AHB1ENR |= RCC_AHB1ENR_DMA1EN;
2019-04-24 10:29 PM
Probably want to start by ORing clock enable bits, rather than blind writing..
RCC->AHB1ENR |= RCC_AHB1ENR_DMA1EN;
2019-04-25 03:22 AM
Thank you ! I have solved the problem.
2019-04-25 03:25 AM
I have one more problem. I cannot received data continuously using DMA, please help me !:
while(1)
{
if (USART_GetFlagStatus(USART2, USART_FLAG_IDLE)==RESET)
{
/* clear buffer */
clear_buffer(SEMEATECH_RECEIVE);
// USART_Cmd(USART2, ENABLE);
USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);
DMA_Cmd(DMA1_Stream5, ENABLE);
}
else if (USART_GetFlagStatus(USART2, USART_FLAG_IDLE)==SET)
{
// USART_Cmd(USART2, DISABLE);
USART_DMACmd(USART2, USART_DMAReq_Rx, DISABLE);
DMA_Cmd(DMA1_Stream5, DISABLE);
UART_DISPLAY_DATA(10);
}
delay_ms(500);
}