Issue with STM32 UART Communication and Data Loss in Continuous Transmission

[syedaayesha]

I am currently working on an STM32-based project using UART for continuous data transmission between the microcontroller and a PC application.

The system works fine initially, but I am facing intermittent data loss and incomplete packets during long-running communication. The issue becomes more noticeable when the baud rate is increased or when multiple interrupts are active in the system.

What I have already tried:

• Verified baud rate and clock configuration in STM32CubeMX
• Enabled UART interrupt-based receiving
• Increased buffer size for RX handling
• Checked wiring and physical connection stability

Despite this, the problem still occurs randomly after some time of operation.

I would like to ask the community:

• What are the best practices for stable UART communication in STM32 under continuous data flow?
• Should I switch to DMA-based UART instead of interrupt mode for better reliability?
• Are there any known issues with buffer overflow or interrupt priority that could cause this behavior?

Any guidance or real-world experience would be greatly appreciated.

[TDK]

Use HAL_UARTEx_ReceiveToIdle_DMA with a circular buffer. You will get no data loss, provided you handle the data in a reasonable time frame.

[mƎALLEm]

Hello,

What STM32 part number are you using?

[Andrew Neil]

How do you detect the loss?

What testing have you done to find where the data is being lost:

• on the PC side ?
• on the STM32 side ?
• both ?

Does the loss correlate with anything else happening in the system?

Are UART errors occurring (framing, overrun, etc) ?

Is your interrupt handling tight and efficient?

Are your interrupt priorities well thought out?