STM32WB cannot connect to adafruit feather through I2C

[QQian.1]

Hi there,

I tried to set STM32 as the master and adafruit feather ESP8266 as the slave. They are going to communicate through I2C. Below is the configuration of the i2c3 because it is the only port for external sensors:Then I write below code for master STM32:

HAL_StatusTypeDef ret;
uint8_t counter;
uint8_t i2c_addr = 0;
 
MX_I2C3_Init();
 
while (1) {
	for (counter = 0; counter < 255; counter++) {
		ret = HAL_I2C_IsDeviceReady(&hi2c3, (uint16_t)(counter<<1), 3, HAL_MAX_DELAY);
		if(ret == HAL_OK) {
			i2c_addr = counter;
			HAL_GPIO_TogglePin(LED_GPIO_Port, LED_Pin);
		}
	}
	HAL_Delay(500);
}

And code in Arduino for slave feather:

#include <Wire.h>
 
#if defined(ARDUINO_SAMD_ZERO) && defined(SERIAL_PORT_USBVIRTUAL)
  // Required for Serial on Zero based boards
  #define Serial SERIAL_PORT_USBVIRTUAL
#endif
 
int cnt = 0;
 
void receiveEvent(int howMany)
{
  while (1 < Wire.available()) { // loop through all but the last
    char c = Wire.read(); // receive byte as a character
    Serial.print(c); // print the character
  }
  int x = Wire.read(); // receive byte as an integer
  Serial.println(x); // print the integer
}
 
void setup() {
  // put your setup code here, to run once:
  Wire.begin(2);
  Wire.onReceive(receiveEvent);
  Serial.begin(9600);
}
 
void loop() {
  // put your main code here, to run repeatedly:
  delay(100);
}

All I got is `HAL_ERROR`. But I can receive something on SDA (so as SCL):

For hardware connection, I connected two 10k pull-up resistors to SDA and SCL. Did I do something wrong? I really appreciate any help to this problem !!

[Foued_KH]

Hello @QQian.1​ ,

Please check the error flags set in the status register and try to get the error (HAL_I2C_GetError).

Make sure you are using correct parameters for this function HAL_I2C_IsDeviceReady().

Foued

[QQian.1]

Thanks for the reply. I tested and got:

HAL_I2C_STATE_READY in hi2c3 state

and HAL_I2C_ERROR_TIMEOUT

Any ideas about this?

[Foued_KH]

Please try to put 4.7k resistor to SDA and SDC each,

GPIO_InitStruct.Pull = GPIO_PULLUP, is often not enough.

[jeonwookyu]

//#include <Wire.h>

//#include <Wire_slave.h>

#define I2C_MASTERSLAVE 1  // 1이면 마스터, 0이면 슬레이브

#define SLAVE_ADDRESS 0x08

#if I2C_MASTERSLAVE == 1  // 마스터

#include <Wire.h>

#endif

#if I2C_MASTERSLAVE == 0  // 슬레이브 모드일 때 사용

#include <Wire_slave.h>

void requestEvent();

void receiveEvent(int numBytes);

 String receivedData = "";

bool stringComplete = false;

#endif

void setup(){

   Wire.begin(SLAVE_ADDRESS);                // join i2c bus with address #4

   Serial.begin(9600);

          // start serial for output

  #if I2C_MASTERSLAVE == 0  // 슬레이브 모드일 때 사용

  Wire.onReceive(receiveEvent); // register event

  Wire.onRequest(requestEvent);  // 요청 이벤트 등록

  receivedData.reserve(200);

  #endif

}

void loop(){

 #if I2C_MASTERSLAVE == 1

 Wire.beginTransmission(SLAVE_ADDRESS);

 Wire.setClock(40000L); // Set speed at 40kHz

  Wire.write("1234567890abcd\n");//종료문자추가

  Wire.endTransmission();

  Serial.println("Sent data to STM32");  // 전송한 데이터 시리얼로 출력

  delay(3000);  // 1초 대기

  #endif

}

#if I2C_MASTERSLAVE == 0

void receiveEvent(int howMany){

 while(Wire.available()){ // loop through all but the last

   char c = (char)Wire.read(); // receive byte as a character

   receivedData += c;

   //Serial.print(c);

    if(c=='\n'){

     stringComplete = true;

    }

     if (stringComplete) {

    Serial.println(receivedData);

    // clear the string:

    receivedData = "";

    stringComplete = false;

  }

 }

}

void requestEvent() {

}

#endif