My customer is facing the issue of "no communication start of UART at low temp(0℃)" on their system.
The UART communication using the USCI port did not start when the power was turned on occurred,
UART is working correctly at room temperature (23 ° C) or high temperature (45 ° C), but it occurs at low temperature.
I have attached the photo of the waveform observed by the oscilloscope at power-on,
Yellow: A signal that outputs Hi / Lo inversion every 200ms while operating with PU.1.
Blue and green: UCA1TXD, after this it should respond after boot, but the signal is falling to Lo (Hi-Z)
Red: UCA1RXD receives startup notification from the system's Main CPU after this
The customer expect the output of TXD drops to Lo 2s after the power is turned on, which is a clue to the problem phenomenon.
Could you advise what we should check like register setting and clock tree selection ?
since we request customer to do it .