I'm trying to get the SPI communications to a peripheral handled by the DMA. I have reviewed the STM32L0 reference manual, and LL libraries, as well as close examples. I am able to get Tx operation working properly. However, I cannot get Rx to work. The Rx variable always shows as empty.
I have been trying this operation in loopback mode, with an external connection between MISO and MOSI. Whatever I send should end up in the receiver variable location. However, this does not happen. Instead, the Rx data variable never changes.
Can I get some insight here?
while (1)
{
mdsendBuffer[0] = i;
Configure_DMA();
Activate_SPI();
WaitAndCheckEndOfTransfer();
}
void Configure_DMA(void)
{
/* DMA1 used for SPI1 Transmission
* DMA1 used for SPI1 Reception
*/
uint8_t temp = 0;
/* (1) Enable the clock of DMA1 and DMA1 */
LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_DMA1);
/* (2) Configure NVIC for DMA transfer complete/error interrupts */
NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0);
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0); // NVIC_SetPriority(DMA1_Channel3_IRQn, 0);
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
/* (3) Configure the DMA1_Channel2 functional parameters, the Receive Channel */
LL_DMA_ConfigTransfer(DMA1, LL_DMA_CHANNEL_2, LL_DMA_DIRECTION_PERIPH_TO_MEMORY | LL_DMA_PRIORITY_HIGH
| LL_DMA_MODE_NORMAL | LL_DMA_PERIPH_NOINCREMENT
| LL_DMA_MEMORY_INCREMENT | LL_DMA_PDATAALIGN_BYTE
| LL_DMA_MDATAALIGN_BYTE);
LL_DMA_ConfigAddresses(DMA1, LL_DMA_CHANNEL_2, LL_SPI_DMA_GetRegAddr(SPI1), (uint32_t)&mdrcvBuffer,
LL_DMA_DIRECTION_PERIPH_TO_MEMORY);
LL_DMA_SetDataLength(DMA1, LL_DMA_CHANNEL_2, sizeof(mdsendBuffer));
//LL_DMA_SetPeriphRequest(DMA1, LL_DMA_CHANNEL_2, LL_DMA_REQUEST_0); ////////////////
/* (4) Configure the DMA1_Channel3 functional parameters, the Transmit Channel */
LL_DMA_ConfigTransfer(DMA1, LL_DMA_CHANNEL_3, LL_DMA_DIRECTION_MEMORY_TO_PERIPH | LL_DMA_PRIORITY_HIGH
| LL_DMA_MODE_NORMAL | LL_DMA_PERIPH_NOINCREMENT
| LL_DMA_MEMORY_INCREMENT | LL_DMA_PDATAALIGN_BYTE
| LL_DMA_MDATAALIGN_BYTE);
LL_DMA_ConfigAddresses(DMA1, LL_DMA_CHANNEL_3, (uint32_t)&mdsendBuffer, LL_SPI_DMA_GetRegAddr(SPI1),
LL_DMA_DIRECTION_MEMORY_TO_PERIPH);
LL_DMA_SetDataLength(DMA1, LL_DMA_CHANNEL_3, sizeof(mdsendBuffer));
//LL_DMA_SetPeriphRequest(DMA1, LL_DMA_CHANNEL_3, LL_DMA_REQUEST_0); /////////////////
/* (5) Enable DMA interrupts complete/error */
LL_DMA_DisableIT_HT(DMA1, LL_DMA_CHANNEL_2);
LL_DMA_EnableIT_TC (DMA1, LL_DMA_CHANNEL_2);
LL_DMA_EnableIT_TE (DMA1, LL_DMA_CHANNEL_2);
LL_DMA_DisableIT_HT(DMA1, LL_DMA_CHANNEL_3);
LL_DMA_EnableIT_TC (DMA1, LL_DMA_CHANNEL_3);
LL_DMA_EnableIT_TE (DMA1, LL_DMA_CHANNEL_3);
}
void Activate_SPI(void)
{
/* Enable SPI1 */
CS_MSA_ON;
LL_SPI_Enable(SPI1);
NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0);
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0);
NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
/* Enable DMA Channels */
LL_DMA_EnableChannel(DMA1, LL_DMA_CHANNEL_2);
LL_DMA_EnableChannel(DMA1, LL_DMA_CHANNEL_3);
}
static void MX_SPI1_Init(void)
{
/* USER CODE BEGIN SPI1_Init 0 */
/* USER CODE END SPI1_Init 0 */
LL_SPI_InitTypeDef SPI_InitStruct = {0};
LL_GPIO_InitTypeDef GPIO_InitStruct = {0};
/* Peripheral clock enable */
LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_SPI1);
LL_IOP_GRP1_EnableClock(LL_IOP_GRP1_PERIPH_GPIOA);
/**SPI1 GPIO Configuration
PA5 ------> SPI1_SCK
PA6 ------> SPI1_MISO
PA7 ------> SPI1_MOSI
*/
GPIO_InitStruct.Pin = LL_GPIO_PIN_5;
GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = LL_GPIO_PIN_6;
GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.Pin = LL_GPIO_PIN_7;
GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
GPIO_InitStruct.Alternate = LL_GPIO_AF_0;
LL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* SPI1 DMA Init */
/* SPI1_TX Init */
LL_DMA_SetPeriphRequest(DMA1, LL_DMA_CHANNEL_3, LL_DMA_REQUEST_1);
LL_DMA_SetDataTransferDirection(DMA1, LL_DMA_CHANNEL_3, LL_DMA_DIRECTION_MEMORY_TO_PERIPH);
LL_DMA_SetChannelPriorityLevel(DMA1, LL_DMA_CHANNEL_3, LL_DMA_PRIORITY_LOW);
LL_DMA_SetMode(DMA1, LL_DMA_CHANNEL_3, LL_DMA_MODE_NORMAL);
LL_DMA_SetPeriphIncMode(DMA1, LL_DMA_CHANNEL_3, LL_DMA_PERIPH_NOINCREMENT);
LL_DMA_SetMemoryIncMode(DMA1, LL_DMA_CHANNEL_3, LL_DMA_MEMORY_INCREMENT);
LL_DMA_SetPeriphSize(DMA1, LL_DMA_CHANNEL_3, LL_DMA_PDATAALIGN_BYTE);
LL_DMA_SetMemorySize(DMA1, LL_DMA_CHANNEL_3, LL_DMA_MDATAALIGN_BYTE);
/* USER CODE BEGIN SPI1_Init 1 */
/* USER CODE END SPI1_Init 1 */
/* SPI1 parameter configuration*/
SPI_InitStruct.TransferDirection = LL_SPI_FULL_DUPLEX;
SPI_InitStruct.Mode = LL_SPI_MODE_MASTER;
SPI_InitStruct.DataWidth = LL_SPI_DATAWIDTH_8BIT;
SPI_InitStruct.ClockPolarity = LL_SPI_POLARITY_LOW;
SPI_InitStruct.ClockPhase = LL_SPI_PHASE_1EDGE;
SPI_InitStruct.NSS = LL_SPI_NSS_SOFT;
SPI_InitStruct.BaudRate = LL_SPI_BAUDRATEPRESCALER_DIV2;
SPI_InitStruct.BitOrder = LL_SPI_MSB_FIRST;
SPI_InitStruct.CRCCalculation = LL_SPI_CRCCALCULATION_DISABLE;
SPI_InitStruct.CRCPoly = 7;
LL_SPI_Init(SPI1, &SPI_InitStruct);
LL_SPI_SetStandard(SPI1, LL_SPI_PROTOCOL_MOTOROLA);
/* USER CODE BEGIN SPI1_Init 2 */
GPIO_InitStruct.Mode = LL_GPIO_MODE_INPUT;
LL_SPI_Enable(SPI1);
LL_SPI_EnableDMAReq_RX(SPI1);
/* Enable DMA TX Interrupt */
LL_SPI_EnableDMAReq_TX(SPI1);
/* USER CODE END SPI1_Init 2 */
}
