SLAZ224P October 2012 – May 2021 MSP430F46191
USCI Module
Functional
LPM4 may affect USCI operation
When SMCLK is used as the USCI clock source, and SMCLK gets deactivated due to a LPM4 entry, ongoing SPI master, I2C master, and UART transmit transaction will be interrupted. Also, while in LPM4, UART receive operation is non-functional.
Do not enter LPM4 while SPI master, I2C master, or UART transmit operations are active. Wait for the operation to be completed prior entering LPM4, or enter a different low-power mode instead. Also, do not use LPM4 in case of UART receive operation. Instead, use a different low-power mode.