Posted on June 15, 2015 at 12:57
Hello
I am a beginner in using STM32 devices, so please tell me if I am doing something incredibly wrong here. I am trying to enable DMA for SPI on STM21F411RE but I keep getting TEIF error on the SPI3 channel for DMA1 Stream 5. Here is DMA initialization code:
/*******************************************************************************************************************/
// DMA for SPI3: DMA1, Channel 0, Stream 5
DMA1->HIFCR = 0xffff;
DMA1->LIFCR = 0xffff; // clear interrupt flags for all streams
RCC->AHB1ENR |= RCC_AHB1ENR_DMA1EN; // Enable clock for DMA1
DMA1_Stream5->NDTR = 1; // One data item per transfer (1 byte)
DMA1_Stream5->PAR = (uint32_t) &SPI3->DR; // Peripheral address register (address of SPI3 DR)
// FIFO disabled (direct mode)
SPI3->CR2 |= SPI_CR2_TXDMAEN; // Enable DMA for SPI
NVIC_EnableIRQ(DMA1_Stream5_IRQn); // Enable DMA interrupt for the stream
DMA1_Stream5->CR = ((DMA_SxCR_CHSEL_0 | DMA_SxCR_CHSEL_2) | (DMA_SxCR_PL_0) | (DMA_SxCR_DIR_0) | (DMA_SxCR_TCIE));
// Channel 0, Stream 5 (SPI3 TX)
// Single memory burst transfer
// No buffer switching
// Medium priority
// Memory data size 1 byte
// Peripheral data size 1 byte
// Memory address pointer is fixed
// Peripheral address pointer is fixed
// Circular mode disabled
// Transfer direction: memory to peripheral
// The DMA is flow controller
// Transfer complete interrupt enable
/*******************************************************************************************************************/
I am enabling SPI3 before running the above code (works fine without DMA). In the debugger, I am able to see that the code runs fine and all the bits are set. Here are my two send routines:
void _TFT_DMA_wr_cmd(const uint8_t cmd) {
TFT_DC(0); // DC = 0 (command)
TFT_CS(0); // Select chip
SPI3->CR1 &= ~SPI_CR1_SPE; // Disable peripheral
DMA1->HIFCR = 0xffff;
DMA1->LIFCR = 0xffff; // clear interrupt flags for all streams
DMA2_Stream5->M0AR = cmd; // Put command in MOAR register
DMA1_Stream5->CR |= DMA_SxCR_EN; // Enable DMA
SPI3->CR1 |= SPI_CR1_SPE; // Enable peripheral
SPI3->SR |= SPI_SR_TXE; // Request transfer
}
void _TFT_DMA_wr_data(uint8_t data) {
TFT_DC(1); // DC = 1 (data)
TFT_CS(0); // Select chip
SPI3->CR1 &= ~SPI_CR1_SPE; // Disable peripheral
DMA1->HIFCR = 0xffff;
DMA1->LIFCR = 0xffff; // clear interrupt flags for all streams
DMA2_Stream5->M0AR = data; // Pud data in MOAR
DMA1_Stream5->CR |= DMA_SxCR_EN; // Enable DMA
SPI3->CR1 |= SPI_CR1_SPE; // Enable peripheral
SPI3->SR |= SPI_SR_TXE; // Request transfer
}
The problem arises in the following two lines:
DMA2_Stream5->M0AR = data; // Pud data in MOAR
DMA1_Stream5->CR |= DMA_SxCR_EN; // Enable DMA
When I run the code line by line I see that the data is not being copied in M0AR register, and immediately after trying to enable DMA I get an flag raised - the TEIF5 flag. No error flags are raised for the SPI peripheral. The datasheet states that ''TEIF is set when a bus error occurs during a DMA read or a write access''.
Any help will be greatly appreciated. Thanks
#dma #spi
