#include "Wire.h"
TwoWire bus1(0);
TwoWire bus2(1);

void setup() {
  Serial.begin(115200);
  bus1.begin(17, 16);
  bus2.begin(21, 20);
}

void loop() {
  byte error, address;
  int nDevices = 0;

  delay(5000);

  Serial.println("Scanning for I2C devices on bus 1...");
  for (address = 0x01; address < 0x7f; address++) {
    bus1.beginTransmission(address);
    error = bus1.endTransmission();
    if (error == 0) {
      Serial.printf("I2C device found at address 0x%02X\n", address);
      nDevices++;
    } else if (error != 2) {
      Serial.printf("Error %d at address 0x%02X\n", error, address);
    }
  }

  Serial.println("Scanning for I2C devices on bus 2...");
  for (address = 0x01; address < 0x7f; address++) {
    bus2.beginTransmission(address);
    error = bus2.endTransmission();
    if (error == 0) {
      Serial.printf("I2C device found at address 0x%02X\n", address);
      nDevices++;
    } else if (error != 2) {
      Serial.printf("Error %d at address 0x%02X\n", error, address);
    }
  }

  if (nDevices == 0) {
    Serial.println("No I2C devices found");
  }
}