Solved
STM32 memory to memory DMA with Timer
Hi, I am trying to do MemToMem DMA operation on Timer input capture.
My code:
#define BufferSize 1000
uint16_t BUFFER_DATA[BufferSize];
TIM_HandleTypeDef htim = htim3;
DMA_HandleTypeDef hdma = hdma_tim3_ch4_up;
uint32_t channel = TIM_CHANNEL_4;
uint32_t dma_cc = TIM_DMA_CC4;
uint32_t dma_id_cc = TIM_DMA_ID_CC4;
hdma.Init.Direction = DMA_MEMORY_TO_MEMORY;
htim.hdma[dma_id_cc]->XferCpltCallback = TIM_DMACaptureCplt;
htim.hdma[dma_id_cc]->XferHalfCpltCallback = TIM_DMACaptureHalfCplt;
htim.hdma[dma_id_cc]->XferErrorCallback = TIM_DMAError;
/* Enable the DMA channel */
HAL_DMA_Start_IT(htim.hdma[dma_id_cc], (uint32_t)&GPIOC->IDR, (uint32_t)&BUFFER_DATA[0], BufferSize);
/* Enable the TIM Capture/Compare 1 DMA request */
__HAL_TIM_ENABLE_DMA(&htim, dma_cc);
/* Enable the Input Capture channel */
TIM_CCxChannelCmd(htim.Instance, channel, TIM_CCx_ENABLE);
/* Enable the Peripheral, except in trigger mode where enable is automatically done with trigger */
__HAL_TIM_ENABLE(&htim);How do I get exact value of (uint32_t)&GPIOC->IDR when timer pin goes low?
Do I need to wait half or full captured interrupt?
Which array element in BUFFER_DATA will be the exact (uint32_t)&GPIOC->IDR value? Or there is no way to tell and I need to loop through BUFFER_DATA and guess?
It seems to me that DMA just copies data to the buffer non-stop and timer just gives me the interupt and thats it, so I need to guess which value do I need to pick from the array, as the timer interupt and DMA are out of sync?
