ESP32_OSC_IMU/lib/M5Stack/examples/Unit/LASER/LASER.ino

/*
    Description: LASER Unit wireless UART application: burn the program to two M5Cores
    And connect LASER.TX and LASER.RX to PORTC port respectively. 
    Point LASER.TX to LASER.RX and press the button on the panel to send characters to the receiver of LASER.RX.
*/

#include <M5Stack.h>

char ch;
// serial 2 write and read
//#define RX 
void setup() {

  M5.begin();
  M5.Power.begin();
  Serial.begin(115200);

  // Serial2.begin(unsigned long baud, uint32_t config, int8_t rxPin, int8_t txPin, bool invert)
  Serial2.begin(9600, SERIAL_8N1, 16, 17);
  pinMode(5, OUTPUT);
  digitalWrite(5, 1);

  M5.Lcd.setTextSize(4);
  M5.Lcd.setTextColor(GREEN);
  M5.Lcd.setCursor(60, 50);
#ifdef RX
  M5.Lcd.print("LASER RX");
#elif defined TX
  M5.Lcd.print("LASER TX");
#else
  M5.Lcd.setCursor(30, 50);
  M5.Lcd.print("LASER TX/RX");
  M5.Lcd.setCursor(50, 200);
  M5.Lcd.print('A');
  M5.Lcd.setCursor(150, 200);
  M5.Lcd.print('B');
  M5.Lcd.setCursor(240, 200);
  M5.Lcd.print('C');
#endif
  M5.Lcd.setCursor(0, 100);
}

void loop() {

#ifdef RX 
M5.update();
 if(Serial2.available()) {
    char ch = Serial2.read();
    M5.Lcd.print(ch);
 }

  if (M5.BtnA.wasReleased()) {
    M5.Lcd.clear();
    M5.Lcd.setCursor(0, 0);
  }
#elif defined TX
    Serial2.write('A');
    delay(50);
#else
  if (M5.BtnA.wasReleased()) {
    ch = 'A';
    Serial2.write(ch);
  } else if (M5.BtnB.wasReleased()) {
    ch = 'B';
    Serial2.write(ch);
  } else if (M5.BtnC.wasReleased()) {
    ch = 'C';
    Serial2.write(ch);
  }
  M5.update();
 if(Serial2.available()) {
    char ch = Serial2.read();
    M5.Lcd.print(ch);
 }
#endif


}