SAMD21 Serial port problem

Other Hardware 3rd Party Boards
1

Hi,

I am having an issue with a SAMD21 module from Adafruit with the serial port. I am using the built in TX/RX hardware port and I can see all my data in the serial monitor. However I have the TX/RX pins connected to a MAX3232 driver IC. I am not able to see ANY data on the physical TX pin.

I then tried another Module with no MAX3232 chip and I still cannot see any data

Below is the sample I am using. I even tried to use Serial.Write, and like before it shows up in the serial monitor but there is no data on the actual TX pin. I am using 9600 baud, and I have set the scope to 100uS sweep time. Im thinking it uses the USB UART, but how do I set this to transmit directly out of the Physical TX pin?

void setup(){
  Serial.begin(9600);
}

void loop(){
  Serial.write(45); // send a byte with the value 45

   int bytesSent = Serial.write("hello"); //send the string "hello" and return the length of the string.
}

Attached is my setup, any help is appreciated.

Thanks

mike

ToForum.JPG
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2

Not familiar with SAM boards. But do SAM boards not use native USB instead of TX/RX when communicating over the USB connector?

Which board do you have exactly?

3

Use Serial1 for the UART Tx/Rx. Serial is the USB console serial port.

4

Hi,

Thanks you for the Serial 1 information, it works!! I am using the Adafruit M0 Adalogger module.
I could not see the forest through the trees!!!

Thanks

mike