Communication between Genuino Zero and Arduino Uno using UART

Question

I want to make my Arduino Uno and Genuino Zero communicate using UART. My Genuino Zero is the transmitter and the receiver is the Arduino Uno.

For the Arduino Uno, I am using the SoftSerial library. I have uploaded the transmitter and receiver codes.

My connection is as below:

Genuino Zero (RX) pin 0 ---------------- Arduino Uno pin 11

Genuino Zero (TX) pin1 ---------------- Arduino Uno pin 10

Ground ---------------------------------- Ground

The Arduino Uno's pin 10 is Rx and pin 11 is Tx, using SoftSerial.

The transmitter transmits 'a'. The receiver receives 'a' and turns a LED on. My problem is that on the receiver, I am not getting anything.

My code is here:

https://www.dropbox.com/s/4w8o2h2k4zs0it5/transmitter.txt?dl=0 https://www.dropbox.com/s/d50uizoz3iove9w/receiver.txt?dl=0

-------------------receiver---------------------

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
/* Simple Serial ECHO script : Written by ScottC 03/07/2012 */
/* Use a variable called byteRead to temporarily store
 the data coming from the computer */
byte byteRead;
void setup() { 
// Turn the Serial Protocol ON
 Serial.begin(9600);
 mySerial.begin(9600);
 pinMode(LED_BUILTIN, OUTPUT);
}
void loop() {
 char a[8];
 /* check if data has been sent from the computer: */
 if (Serial.available()) {
 /* read the most recent byte */
 byteRead = Serial.read();
 Serial.print("rushin\r\n");
 /*ECHO the value that was read, back to the serial port. */
 if(byteRead == 0x61) {
 digitalWrite(LED_BUILTIN, HIGH);
 Serial.write(byteRead);
 }
 }
 if (mySerial.available()) {
 /* read the most recent byte */
 byteRead = mySerial.read();
 mySerial.print("rushin\r\n");
 /*ECHO the value that was read, back to the serial port. */
 if(byteRead == 0x61) {
 digitalWrite(LED_BUILTIN, HIGH);
 mySerial.write(byteRead);
 }
 }
}
-------------------transmitter----------------------------------
/*
 DigitalReadSerial
 Reads a digital input on pin 2, prints the result to the serial monitor
 This example code is in the public domain.
 */
// digital pin 2 has a pushbutton attached to it. Give it a name:
int pushButton = 7;
// the setup routine runs once when you press reset:
void setup() {
 // initialize serial communication at 9600 bits per second:
 Serial.begin(9600);
 // make the pushbutton's pin an input:
 pinMode(pushButton, INPUT);
}
// the loop routine runs over and over again forever:
void loop() {
 // read the input pin:
 int buttonState = digitalRead(pushButton);
 // print out the state of the button:
 Serial.println("a");
 delay(1000);
 // delay in between reads for stability
}

• gre_gor: Post the code here. Links tend to disappear.
• Beginner: sorry. can't upload text file here. and link is ok
• gre_gor: Just copy paste the code here and format it into code block.
• Mikael Patel: What does the product information say? "Unlike most Arduino & Genuino boards, the Zero runs at 3.3V. The maximum voltage that the I/O pins can tolerate is 3.3V. Applying voltages higher than 3.3V to any I/O pin could damage the board."
• Beginner: yes i know that. and i am working with 3.3 v

Answer 1

Your Arduino Zero transmitter code transmits to the USB Serial ('Serial') only. If you want it to transmit to the serial comm on pin 0 and pin 1, you must have it write to Serial1. (Check variants.cpp file ) you will see that Serial1 is uses SERCOM0 which is on pin 0 and 1.

So, Your code should look like this (noitce "Serial" is replaced with "Serial1"):

void setup() {
 // initialize serial communication at 9600 bits per second:
 Serial1.begin(9600);
 // make the pushbutton's pin an input:
 pinMode(pushButton, INPUT);
}
// the loop routine runs over and over again forever:
void loop() {
 // read the input pin:
 int buttonState = digitalRead(pushButton);
 // print out the state of the button:
 Serial1.println("a");
 delay(1000);
 // delay in between reads for stability
}