SLAAEG4 October 2023 MSPM0C1104 , MSPM0L1306
ODIO are tolerant to 5-V input. Because they are open drain, an external pullup resistor is needed for the pin to be able to output high. This I/O can used for UART or I2C interface with different voltage levels. To limit the current, a series resistor must be placed between the pin and the pullup resistor, and the RSERIES must be no less than 250 Ω. As shown in Figure 8-1, TI recommends 270 Ω. The value of the pullup resistor depends on the output frequency (see I2C and SPI Design Considerations).