[Arduino code for KC868-A32 Pro]-03 read / write by RS485

Code:
#include <arduino.h>

#include "HardwareSerial.h"

String comdata1,comdata2;

HardwareSerial my485Serial(1);

void setup() {

  // put your setup code here, to run once:

  Serial.begin(115200);

  my485Serial.begin(9600,SERIAL_8N1,8,9);///rx:32  tx:33

  Serial.println("UsbSerial say hello");

  my485Serial.println("R485 say hello");

}



void loop() {

  // put your main code here, to run repeatedly:

  

    while (my485Serial.available() > 0) {

      delay(100);

      comdata1 = my485Serial.readString();

      my485Serial.print("R485.readString:");

      my485Serial.println(comdata1);

    }

    while (Serial.available() > 0) {

        delay(100);

      comdata1 = Serial.readString();

      Serial.print("UsbSerial.readString:");

      Serial.println(comdata1);

    }

}