If PA25 is left high or unconnected, the G400 uses USB for debugging. If it’s grounded then serial port is used for debug purpose. Should we put a pulldown resistor if we want serial debug? I plan to have a jumper to select or not the USB/Serial mode. On EMX a 2.2k resistor was inserted to ground the pin.
@ leforban - A pull down resistor is not absolutely necessary. A simple jumper to ground will be sufficient. However, if a pull-down is used, we do not recommend using this pin as an output.
Hello Aron and thanks for your answer. This makes senses