Ini
[env:esp32-s3-devkitc-1]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
lib_deps =
    arduino-libraries/Ethernet@^2.0.2
    4-20ma/ModbusMaster@^2.0.1

Cpp
#include <Arduino.h>
#include <SPI.h>
#include <Wire.h>
#include <Ethernet.h>
#include <ModbusMaster.h>

#define ETH_SCK 12
#define ETH_MOSI 11
#define ETH_MISO 13
#define ETH_CS 10
#define ETH_INT 9
#define ETH_RST 8

#define RS485_TX 17
#define RS485_RX 16
#define RS485_DE_RE 4

#define I2C_SDA 1
#define I2C_SCL 2
#define IOEXP_INT 3

#define GSM_RX_FROM_MODEM 15
#define GSM_TX_TO_MODEM 14
#define GSM_PWRKEY 18
#define GSM_RESET 21

#define P4_SPI_SCK 35
#define P4_SPI_MOSI 36
#define P4_SPI_MISO 37
#define P4_SPI_CS 38
#define P4_IRQ 47
#define P4_READY 48

HardwareSerial RS485Serial(2);
HardwareSerial GSMSerial(1);
ModbusMaster modbus;

void rs485PreTransmission(){ digitalWrite(RS485_DE_RE, HIGH); }
void rs485PostTransmission(){ digitalWrite(RS485_DE_RE, LOW); }

void resetEthernet(){
  pinMode(ETH_RST, OUTPUT);
  digitalWrite(ETH_RST, LOW); delay(10);
  digitalWrite(ETH_RST, HIGH); delay(100);
}

void setup(){
  Serial.begin(115200);
  pinMode(RS485_DE_RE, OUTPUT); digitalWrite(RS485_DE_RE, LOW);
  pinMode(GSM_PWRKEY, OUTPUT); digitalWrite(GSM_PWRKEY, HIGH);
  pinMode(GSM_RESET, OUTPUT); digitalWrite(GSM_RESET, HIGH);
  pinMode(ETH_INT, INPUT_PULLUP);
  pinMode(IOEXP_INT, INPUT_PULLUP);
  pinMode(P4_IRQ, INPUT_PULLUP);
  pinMode(P4_READY, OUTPUT); digitalWrite(P4_READY, LOW);

  Wire.begin(I2C_SDA, I2C_SCL);
  RS485Serial.begin(9600, SERIAL_8N1, RS485_RX, RS485_TX);
  modbus.begin(1, RS485Serial);
  modbus.preTransmission(rs485PreTransmission);
  modbus.postTransmission(rs485PostTransmission);

  GSMSerial.begin(115200, SERIAL_8N1, GSM_RX_FROM_MODEM, GSM_TX_TO_MODEM);

  SPI.begin(ETH_SCK, ETH_MISO, ETH_MOSI, ETH_CS);
  resetEthernet();
  Ethernet.init(ETH_CS);
  byte mac[] = {0xDE,0xVA,0x00,0x00,0x00,0x01};
  Ethernet.begin(mac);
  digitalWrite(P4_READY, HIGH);
  Serial.println("S3 controller booted");
}

void loop(){
  static uint32_t last = 0;
  if (millis() - last > 1000) {
    last = millis();
    GSMSerial.println("AT");
    uint8_t result = modbus.readHoldingRegisters(0x0000, 1);
    Serial.printf("Modbus result: 0x%02X, Ethernet link: %d\n", result, Ethernet.linkStatus());
  }
}