通过I2C连接Arduino和esp 32时出错

Question

我无法将esp32与arduino pro mini 3v3连接。我的代码与arduino教程示例相同。我使用原子进行编码，当我打开终端串行消息时写空消息

主代码（运行ESP32）

 #include <Wire.h>
int i=0;
char c[20
];
#include <Wire.h>
#define I2C_SDA_PIN 21
#define I2C_SCL_PIN 22
void setup() {
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
}

void loop() {
  Wire.requestFrom(8, 1);    // request 6 bytes from slave device #8

  while (Wire.available()>0) { // slave may send less than requested
     c[i]=Wire.read(); // receive a byte as character
     i++;
    Serial.print(c);         // print the character
  }
}

运行Arduino pro mini

#include <Wire.h>

void setup() {
  Wire.begin(8);                // join i2c bus with address #8
  Wire.onRequest(requestEvent); // register event
}

void loop() {
  delay(100);
}
// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent() {
  Wire.write('h'); // respond with message of 6 bytes
  // as expected by master
}

我进行了i2c总线地址测试并识别出arduino：screenshot 如果有人可以帮助，我什么也找不到

对不起，我英语不好。