I2C communication problem between two STM32s

[JingtaiChen]

Hello everyone, I have written a case of I2C communication between two STM32 development boards. The two chips used are STM32F103C8T6. At the beginning, I used two Arduino Uno. Run the procedure on There is no problem with the order, but when it is run on two STM32 development boards after rewriting, they can only communicate once, and then they can not communicate. I hope you can propose a solution to my case, thank you.

// 主机(master)
HardwareSerial Serial1(PA10, PA9); // RX,TX/硬件串口调用(void setup()前)
#include <Wire.h>
TwoWire Wire1(PB7, PB6); // SDA,SCL/I2C接口重定义

// 定义从机地址
#define I2C1_ADDR 0x55  // 目标地址1

// 定义用于主机发送/接收的字符串(不大于16字节)
String MasterTransmission_Str;  // 创建发送信息串
String MasterReceived_Str;      // 创建接收信息串

// 发送/接收函数头
int I2C1_Transmission(uint8_t TADDR, String TStr);  // I2C1发送函数(发送地址,发送的信息),返回是否发送成功的信息(0成功)
String I2C1_Received(uint8_t RADDR);                // I2C1接收函数(接收地址),返回接收的信息

void setup() {
  // 初始化
  Serial1.begin(115200);
  Wire1.begin();
  delay(1000);
}

void loop() {
  // 数据发送
  MasterTransmission_Str = analogRead(A0);                           // 发送数据
  int I2C_T = I2C1_Transmission(I2C1_ADDR, MasterTransmission_Str);  // 发送函数(发送的地址,发送的信息)
  Serial1.print("主机发送的信息:");
  Serial1.print(MasterTransmission_Str);
  Serial1.print(";主机发送的状态:");
  Serial1.println(I2C_T);

  // 数据接收
  MasterReceived_Str = "";  // 清空待接收数据
  MasterReceived_Str = I2C1_Received(I2C1_ADDR);
  Serial1.print("主机接收的信息:");
  Serial1.println(MasterReceived_Str);

  delay(500);
}

// 发送函数
int I2C1_Transmission(uint8_t TADDR, String TStr)  // I2C1发送函数(发送地址,发送的信息)
{
  int E = -1;
  Wire1.beginTransmission((uint8_t)TADDR);  // 开始传输
  Wire1.print(TStr);                        // 向从机发送信息
  E = Wire1.endTransmission(true);          // 结束传输(返回错误代码)
  return E;
}

// 接收数据
String I2C1_Received(uint8_t RADDR)  // I2C1接收函数(接收地址)
{
  int R = Wire1.requestFrom((uint8_t)RADDR, 16);  // 向从机发送16字节的请求
  char R_Char[R];                                // 创建一个接收数组R_Char
  Wire1.readBytes(R_Char, R);                     // 将读取的信息放置R_Char数组
  String R_Str = "";                             // 清空返回数据
  for (int i = 0; i < R; i++)                    // 将Received_Message数组拼接成一串字符串
  {
    if (R_Char[i] == (char)0xff)  // 用于截取有效数据段
      break;
    R_Str = R_Str + R_Char[i];
    
  }
  return R_Str;
}

// 从机(slave)
HardwareSerial Serial1(PA10, PA9); // RX,TX/硬件串口调用(void setup()前)
#include <Wire.h>
TwoWire Wire1(PB7, PB6); // SDA,SCL/I2C接口重定义

// 定义从机地址
#define I2C_ADDR 0x55

// 定义用于从机发送/接收的字符串(不大于16字节)
String SlaveTransmission_Str;  // 创建发送信息串
String SlaveReceived_Str;      // 创建接收信息串

// 向主机发送信息
void onRequest() {
  SlaveTransmission_Str = "";              // 清空
  SlaveTransmission_Str = analogRead(A0);  // 赋值

  String T_Str = "";  // 清空待发送数据
  T_Str = SlaveTransmission_Str;
  Wire1.print(T_Str);

  Serial1.print("从机发送的信息:");
  Serial1.println(SlaveTransmission_Str);
}

// 从主机接收消息
void onReceive(int len) {
  SlaveReceived_Str = "";  // 清空

  String R_Str = "";  // 清空返回数据
  while (Wire1.available()) {
    R_Str = R_Str + char(Wire1.read());  // char()强制将ASCII转换为字符
  }
  SlaveReceived_Str = R_Str;

  Serial1.print("从机接收的信息:");
  Serial1.println(SlaveReceived_Str);
}

void setup() {
  Serial1.begin(115200);
  Wire1.onRequest(onRequest);  // 开启发送函数
  Wire1.onReceive(onReceive);  // 开启接收函数
  Wire1.begin((uint8_t)I2C_ADDR);
}

void loop() {
}

[fpistm]

Do you have pullup resources on each I2C lines?

[JingtaiChen]

Yes, otherwise the first communication data would not have been sent successfully.

[fpistm]

Well normally yes but I preferred asked 😉
Which target you select in the menu for your STM32F103C8T6?

[JingtaiChen]

I don't quite understand what you mean, but I have attached the screenshot of Arduino configuration.

[fpistm]

Could you try the default examples from Wire for master and slave?

[JingtaiChen]

Yes, they had no problem with communication before. I think there is something wrong with my case, but I don't know where the problem is.

[fpistm]

AS the default example works I close this one. Tested and it works too.