Question
STM32F4: SPI output using DMA with LL driver
Hi
I'm trying to get SPI output working using DMA with the LL drivers. I'm using CubeMX to set up the DMA and SPI and it works perfectly when I use HAL_SPI_Transmit_DMA to initiate the output. However, this is a very slow routine and I want to be able to initiate re-transmission as fast as possible. My code is attached below but I don't see any output. I'm clearly missing a bit of the jigsaw but can't find any examples to guide me.
Once I've got basic transmission working then I can pare back the routines in the loop to find the minimum needed to re-transmit.
The LED on PD8 is toggling so I know the loop is running
Help would be appreciated
while (1)
{
HAL_Delay(500);
HAL_GPIO_TogglePin(GPIOD, GPIO_PIN_8);
// Disable DMA to load new length to be transmitted
LL_DMA_DisableIT_TC(DMA2,
LL_DMA_STREAM_3);
LL_DMA_SetDataLength(DMA2,
LL_DMA_STREAM_3,
sizeof(dmabuff));
LL_DMA_ConfigAddresses(DMA2,
LL_DMA_STREAM_3,
(uint32_t)dmabuff,
LL_SPI_DMA_GetRegAddr(SPI1),
LL_DMA_DIRECTION_MEMORY_TO_PERIPH);
LL_SPI_EnableDMAReq_TX(SPI1);
LL_SPI_EnableIT_TXE(SPI1);
LL_DMA_EnableIT_TC(DMA2,
LL_DMA_STREAM_3);
LL_DMA_EnableStream(DMA2,
LL_DMA_STREAM_3);
HAL_Delay(500);
// HAL_SPI_Transmit_DMA(&hspi1, dmabuff, sizeof(dmabuff)); // This works perfectly
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}