I have a best practice question.
Correct UART communication requires the transmitter and receiver clocks differ by less than 5% (2.5% per MCU), otherwise communication errors may occur. For the temperature range TA = 0 to 85°C the Accuracy of the HSI oscillator is good enough. But for temperatures below 0°C, the HSI has too less accuracy.
What do you do?
• Use external oscillator
• Use autobaud detection.
• Oscillator calibration with external signal
• Do not care