modbus_slave

/*
library from:
https://github.com/CMB27/ModbusRTUSlave/tree/main
*/

#define MAX485_RXD1 27
#define MAX485_TXD1 26
const byte dePin=13;

#include <ModbusRTUSlave.h>
ModbusRTUSlave modbus(Serial1, dePin); // serial port, driver enable pin for rs-485
bool coils[2];
bool discreteInputs[2];
uint16_t holdingRegisters[2];
uint16_t inputRegisters[2];

void setup() {

  Serial1.begin(9600, SERIAL_8N1, MAX485_RXD1, MAX485_TXD1);

  modbus.configureCoils(coils, 2);                       // bool array of coil values, number of coils
  modbus.configureDiscreteInputs(discreteInputs, 2);     // bool array of discrete input values, number of discrete inputs
  modbus.configureHoldingRegisters(holdingRegisters, 2); // unsigned 16 bit integer array of holding register values, number of holding registers
  modbus.configureInputRegisters(inputRegisters, 2);     // unsigned 16 bit integer array of input register values, number of input registers

  modbus.begin(1, 9600);
}

void loop() {
  modbus.poll();
}