Serial 2 and Serial 3 on SparkFun SAMD21 Mini Breakout

Development Boards Arduino
1

I added Serial 2 and Serial 3 support to the SAMD21 mini Breakout board. I have testet them and are working.

Serial 2
RX = pin 10 TX = pin 12
Serial 3
RX = pin 5 TX = pin 2

By using normal Serial2.begin and Serial3.begin the serial ports are ready for use.

If you dont want to edit the variant files you can only get Serial2 to work.

Here is code for using Serial2 without edit files.

// Serial2 pin and pad definitions (in Arduino files Variant.h & Variant.cpp)
#define PIN_SERIAL2_RX       (34ul)               // Pin description number for PIO_SERCOM on D12
#define PIN_SERIAL2_TX       (36ul)               // Pin description number for PIO_SERCOM on D10
#define PAD_SERIAL2_TX       (UART_TX_PAD_2)      // SERCOM pad 2
#define PAD_SERIAL2_RX       (SERCOM_RX_PAD_3)    // SERCOM pad 3

// Instantiate the Serial2 class
Uart Serial2(&sercom1, PIN_SERIAL2_RX, PIN_SERIAL2_TX, PAD_SERIAL2_RX, PAD_SERIAL2_TX);

void setup()
{
  Serial.begin(115200);
  Serial2.begin(9600);          // Begin Serial2
}

void loop()
{ 
  if (Serial.available())
  {
    byte byteRead2 = Serial.read();
    Serial2.write(byteRead2);
  }
  if (Serial2.available())        // Check if incoming data is available
  {
    byte byteRead = Serial2.read();    // Read the most recent byte 
    Serial.write(byteRead);      // Echo the byte back out on the serial port
  }
}

void SERCOM1_Handler()    // Interrupt handler for SERCOM1
{
  Serial2.IrqHandler();
}

everything abowe void setup must be there, and void SERCOM1_Handler() must NOT be removed.

2

Anyone get Serial3 to work on Pin 5,2? I need 2 hardware serial and the SD card on a mini breakout so I don’t want to use Serial2 from example above. Serial1 in this example is working, Serial3 is not…

// Serial3
#define PIN_SERIAL3_RX       (45ul)               // Pin description number for PIO_SERCOM on D5
#define PIN_SERIAL3_TX       (44ul)               // Pin description number for PIO_SERCOM on D2
#define PAD_SERIAL3_TX       (UART_TX_PAD_2)      // SERCOM pad 2
#define PAD_SERIAL3_RX       (SERCOM_RX_PAD_3)    // SERCOM pad 3

Uart Serial3(&sercom2, PIN_SERIAL3_RX, PIN_SERIAL3_TX, PAD_SERIAL3_RX, PAD_SERIAL3_TX);

void setup()
{
  Serial1.begin(9600);
  Serial3.begin(9600);          // Begin Serial2
}

void loop()
{ 
    Serial1.println("hello1");
    Serial3.println("hello3");
    delay(200);
}

void SERCOM2_Handler()
{
  Serial3.IrqHandler();
}
3

Does anyone have any additional examples of using more than two Serial ports with the SAMD21 mini breakout. The Variants.cpp file link is now gone.