#define BUFFER_SIZE 256

#define LCDHIGH 240
#define LCDWIDTH 320

void setup() {

// initialize the M5Stack object
M5.begin();

//serial Setup
//serial = GPIO 1,3 USB to UART
//serial1 = GPIO 28,29 connect to SD card reader
//serial2 = GPIO 16,17 Extern I/O pin

//serial default setting,8 data bit,No parity,1 stop bit.
Serial.begin(115200);
Serial2.begin(115200,SERIAL_8N1,16,17);//*******(baudrate,config,RX,TX)*******

// Lcd display setup
M5.Lcd.fillScreen(BLACK);
M5.Lcd.setCursor(0,LCDWIDTH / 3);
M5.Lcd.setTextColor(WHITE);ll

M5.Lcd.setTextSize(3);
M5.Lcd.printf(“Start M5stack!!”);
delay(5000);
M5.Lcd.fillScreen(BLACK);
M5.Lcd.setCursor(0,0);
M5.Lcd.setTextColor(WHITE);
M5.Lcd.setTextSize(1);
}

void errorEnd(){
M5.Lcd.fillScreen(BLACK);
M5.Lcd.setCursor(0,0);
M5.Lcd.setTextColor(WHITE);
M5.Lcd.setTextSize(5);
M5.Lcd.printf(“Buffer over flow!”);
for(;;);
}

void loop() {
unsigned char readBuffer[BUFFER_SIZE];
int serialLength;
boolean ba,bb,bc;
boolean ba_1,bb_1,bc_1;
serialLength = Serial.available();
if(serialLength > BUFFER_SIZE -1)errorEnd();
if(serialLength > 0){
Serial.readBytes(readBuffer,serialLength);
readBuffer[serialLength] = ‘\0’;
M5.Lcd.printf(“%s\n\r”,readBuffer);
Serial2.printf(“%s\n\r”,readBuffer);//*******add*******
}

}