Part Number: TM4C123GH6PM Tool/software: Hi everyone, I noticed that in the device data-sheet, Table 24-31 "Fail-Safe GPIOs that Require an External Pull-up" , it is stated that pins PB0 , PB1 , and PE3 require a pull-up resistor (between 1kΩ and 10kΩ) when used as inputs, to maintain a threshold above the minimum VIH during power-on . (Emphasis mine, as I believe this is the source of my doubts.) For PE3 , I was initially planning to use the internal pull-up resistor of the microcontroller, since it's only used to read a DIP switch for configuration purposes. However, adding an external resistor is not a problem. For PB0 and PB1 , I have two different use cases across two designs: In one design, both pins are configured as outputs to control other chips. As I understand it, GPIOs default to input mode on power-up. Would this be a problem in light of the data-sheet's requirement for a pull-up during power-on, since I can’t immediately configure them as outputs? In the other design, both pins are used for UART communication (U1RX/U1TX) and are connected directly to an RS485 transceiver, all powered by the same 3.3V rail. In this case, are external pull-up resistors still necessary? I appreciate any help in clarifying this. Thank you!
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