Hello @Frank_P
To perform a circular transfer, you should use the linked-list of the DMA.
In MX2, you can select CIRCULAR transfer in the DMA configuration on top of the DMA burst configuration in TIM side.
With HAL, you can use HAL_DMA_SetConfigPeriphLinkedListCircularXfer() for the DMA configuration and for the DMA burst configuration in TIM side, HAL_TIM_SetConfigDMABurst(), then the HAL_TIM_StartDMABurst() calls the HAL_DMA_StartPeriphXfer_IT_Opt() function that depending on the previous DMA configuration starts the DMA transfer in DIRECT or CIRCULAR.
So depending, the TIM event you are using in the DMA burst configuration (in TIM side), the DMA burst transfers will be performed circularly on this event.
You can use the existing TIM example hal_tim_pwm_dma_burst and adapt it with the circular mode.
The only thing you should care about is that there is a configuration of a DMA burst length in the TIM DMA burst configuration when calling HAL_TIM_SetConfigDMABurst() and a DMA transfer size (size_byte) when calling HAL_TIM_StartDMABurst().
In the current example, because the DMA burst length is 3 and the number of data to transfer is 6 (in DMA), the CCRx registers will be updated twice.
So, with the circular mode, depending on your buffer, you should adapt the DMA burst length and the DMA transfer size.
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Saket_Om
