Serial communication Error

Official Hardware Mega Due
1

I use Arduino DUE on Arduino IDE 2.3.3. I am facing that Serial1 and Serial2 can't comunicate. I confirmed RX and TX on each Serial is connected to pin on Atmel CPU. when RX1 is received datas, read one and display it. But Data is displayed once after Reset, 2times is not displayed and freezing. Please give me a advise.
---------------------------Source -----------------------------
u_char tx_3b_on[13]= { 0x5A,0x0D,0x3B,0x01,0xC8,0x00,0x0A,0x00,0x0A,0x00,0x0A,0x00,0x00 };
u_char buf[20];
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
while (!Serial); // wait until Serial port (default) open

Serial1.begin(115200); /
while (!Serial1); //wait until Sreial Port (Serial1) open
delay(100);
Serial1.write(tx_3b_on, 13);
}

void loop() {
while (num = Serial1.available()) { // if data xist or not
Serial1.readBytes(buf,num); // read data
Serial.println(buf);
}
delay(100);
}

2

Welcome to the forum

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

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https://forum.arduino.cc/t/how-to-get-the-best-out-of-this-forum

3

Your code does not compile. After fixing the obvious errors, it fails on the Serial.println() with

Compilation error: call of overloaded 'println(u_char [20])' is ambiguous

You can't print an array of unsigned characters like that.

The compiler is also not too happy with while (num = Serial1.available()). I suggest that you set the Compiler warnings under file / preferences to All and check the results.

4

I was tried to execute using another PC. It is correctly operated.
I think that USB port is broken or the USB diriver is bad. My PC is recently introduced. I re-install Arduino IDE. It can operate.

Thanks a lot,