Q: What is the correct way to configure STM32 UART/USART with DMA and interrupts?
Answer
Configure UART TX pin as alternate function push-pull; RX pin as input floating. Enable UART clock before GPIO configuration. Set baud rate: Baud = UARTCLK / (16 x USARTDIV). For high-speed UART (e.g. 1 Mbps) verify clock source provides sufficient granularity. DMA TX should be in normal mode; DMA RX in circular mode for continuous reception. Use IDLE line detection interrupt to detect end-of-frame when using DMA with variable-length packets. For RS-485 control DE (driver enable) pin via GPIO toggled before and after DMA transfer. Use STM32CubeMX to auto-generate init code but verify DMA stream/priority configuration manually for real-time requirements.
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