Arduino ESP32 I2C Slave 的例子

#include <Wire.h>

byte i2c_rcv=0;               // data received from I2C bus

void setup() {
  Wire.begin(0x08);           // join I2C bus as Slave with address 0x08

  // event handler initializations
  Wire.onReceive(dataRcv);    // register an event handler for received data
  Wire.onRequest(dataRqst);   // register an event handler for data request
  Serial.begin(115200);
}

void loop() {
}

//received data handler function
void dataRcv(int numBytes) {
  Serial.print("Slave Received ");
  Serial.print(numBytes);
  Serial.println("Bytes");
  while (Wire.available()) { // read all bytes received
    i2c_rcv = Wire.read();
    Serial.print("[");
    Serial.print(i2c_rcv);
    Serial.print("]");
  }
  Serial.println("");
}

// requests data handler function
void dataRqst() {
    Wire.write(i2c_rcv); // send potentiometer position
    Serial.print("Slave send ");
    Serial.print(i2c_rcv,HEX);
}