Disable UART2 DMA when using DSHOT to avoid DMA conflict #1538
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CF21BL uses DSHOT for brushless motors, which requires DMA1_Stream6. UART2 TX also needs DMA1_Stream6, creating a conflict during ESP32 flashing. Changes: - Guard uart2DmaInit() with #ifndef CONFIG_MOTORS_ESC_PROTOCOL_DSHOT - Guard initialDMACount variable (only used with DMA) - Add fallback in uart2SendDataDmaBlocking() to use interrupt-based uart2SendData() instead when DSHOT is enabled This allows UART2 (and thus ESP32 flashing) to work on CF21BL by avoiding the DMA conflict entirely - UART2 uses interrupts instead of DMA when motors need the stream.
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tobbeanton
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Oct 8, 2025
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CF21BL uses DSHOT for brushless motors, which requires DMA1_Stream6. UART2 TX also needs DMA1_Stream6, creating a conflict, becoming apparent when trying to flash the ESP32 on the AI-deck.
Changes:
This allows UART2 (and thus ESP32 flashing) to work on CF21BL by avoiding the DMA conflict entirely - UART2 uses interrupts instead of DMA when motors need the stream.
Fixes bitcraze/crazyflie-lib-python#550