Serial port stops when ETH activates with POE

[punchcard]

On the Olimex POE ISO the serial port seems to stop when the Ethernet port activates with POE, this does not happen without POE. Strange. Is there a fix for this?

[LubOlimex]

Which pins do you use for the serial port?

You know that you can define any GPIO for serial port, right?

[punchcard]

I did not change the defaults here. I just use:

  Serial.begin(115200);
  Serial.println("hello world");

but as the code proceeds, it prints a control character, then stops printing to the console connected via the USB interface. Is it possible I'm conflicting with one of the GPIOs? What are the default GPIOs for the serial port?

And if I wanted to change those, how do I do that?

Thanks!

[punchcard]

Sorry - Thinking about your statement more. If I'm using GPIO 1,3 and 5 for pullup resistors for push buttons, would that cause a conflict with the serial ports? I see they are marked U0TXD and U0RXD. I'm trying to avoid GPIOs tied to ADC2 as those cause conflict with WiFi. So between that, 3 other input pins for a joystick, i2c for an LCD display, I'm running out of GPIOs for button inputs.

Appreciate any guidance here

Thanks

[LubOlimex]

> I see they are marked U0TXD and U0RXD

Yes, this might bug the serial-USB convertor CH340T. I would not recommend using GPIO1 and GPIO3 if you wish to program the board via USB in future. The best idea is to track the schematic. There should be enough pins for what you are aiming for.

By the way are you using an SD card in your setup? You can use the pins for the SD card if you don't have one inserted.

[punchcard]

Yeah - I switched to different pins and everything is good to go now.

If there is a fix for this in the future, let me know.

Thanks