USART_SR_ORE embedded runtime_error ai_generated true

UART: overrun error (ORE flag set) on USART2

ID: embedded/uart-overrun-error-sr-ore

Also available as: JSON · Markdown · 中文
85%Fix Rate
88%Confidence
1Evidence
2023-11-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
STM32Cube FW_F4 V1.27.1 active — — —
STM32Cube FW_H7 V1.11.0 active — — —
Keil MDK-ARM 5.38 active — — —

Root Cause

UART receive data register was not read before the next byte arrived, causing data loss due to overrun.

generic

中文

UART 接收数据寄存器未能在下一个字节到达前被读取，导致数据因溢出而丢失。

Official Documentation

https://www.st.com/resource/en/reference_manual/dm00031020.pdf

Workarounds

  1. 85% success Enable DMA for UART reception: HAL_UART_Receive_DMA(&huart2, rx_buffer, BUFFER_SIZE); This offloads data transfer from CPU. 
    Enable DMA for UART reception: HAL_UART_Receive_DMA(&huart2, rx_buffer, BUFFER_SIZE); This offloads data transfer from CPU.
  2. 80% success Implement double-buffering with interrupt: use HAL_UARTEx_ReceiveToIdle_DMA to capture data without overrun. 
    Implement double-buffering with interrupt: use HAL_UARTEx_ReceiveToIdle_DMA to capture data without overrun.
  3. 70% success Increase interrupt priority of UART handler to ensure preemptive reading. 
    Increase interrupt priority of UART handler to ensure preemptive reading.

中文步骤

  1. Enable DMA for UART reception: HAL_UART_Receive_DMA(&huart2, rx_buffer, BUFFER_SIZE); This offloads data transfer from CPU.
  2. Implement double-buffering with interrupt: use HAL_UARTEx_ReceiveToIdle_DMA to capture data without overrun.
  3. Increase interrupt priority of UART handler to ensure preemptive reading.

Dead Ends

Common approaches that don't work:

  1. Increase UART baud rate to match incoming data speed 90% fail

    Overrun occurs because the CPU cannot read data fast enough; higher baud rate makes the problem worse, not better.

  2. Disable UART interrupt and poll in main loop 70% fail

    Polling without interrupt may miss data entirely or still overrun if main loop is slow.