I'm trying to test I2C communication between a board(Master) and stm32 board(Slave) with I2c-tools. And I found some troubles.
I thought the slave address is 0x12, but in the ownaddress info of i2c.c, the value is 36, I don't know why.
I just only try i2cdetect, and I found that first connect is successful but next i2cdetect get fail....
This is Master i2c enter image description here
And this is the Uart Image for Slave enter image description here
I will upload the error by UART, and the main.c, i2c.c of stm32 board
<main.c>
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2024 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "i2c.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "stdio.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define SLAVE_ADDRESS 0x12
#define BUFFER_SIZE 32
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
uint8_t rxBuffer[BUFFER_SIZE] = {0};
uint8_t txBuffer[BUFFER_SIZE] = "Hello from STM32!";
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
int __io_putchar(int ch)
{
while(HAL_OK != HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 1000))
{}
return ch;
}
void HAL_I2C_ErrorCallback(I2C_HandleTypeDef *hi2c)
{
if (hi2c->Instance == I2C1)
{
printf("State: 0x%02lX, Error: 0x%02lX\r\n",
(unsigned long)HAL_I2C_GetState(hi2c),
(unsigned long)HAL_I2C_GetError(hi2c));
uint32_t errorCode = HAL_I2C_GetError(hi2c);
printf("I2C Error occurred, Error Code: %lu\r\n", errorCode);
if (errorCode & HAL_I2C_ERROR_AF)
{
printf("Acknowledge Failure: Check address.\r\n");
}
if (errorCode & HAL_I2C_ERROR_TIMEOUT)
{
printf("Timeout Error.\r\n");
}
HAL_I2C_Slave_Receive_IT(&hi2c1, rxBuffer, BUFFER_SIZE);
}
}
void HAL_I2C_AddrCallback(I2C_HandleTypeDef *hi2c, uint8_t TransferDirection, uint16_t AddrMatchCode)
{
if (hi2c->Instance == I2C1)
{
if (TransferDirection == I2C_DIRECTION_TRANSMIT)
{
printf("Address Matched: 0x%02X, Direction: Transmit\r\n", AddrMatchCode);
}
else if (TransferDirection == I2C_DIRECTION_RECEIVE)
{
printf("Address Matched: 0x%02X, Direction: Receive\r\n", AddrMatchCode);
}
}
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
MX_I2C1_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
printf("\r\n I2C Communication Start \r\n");
HAL_I2C_Slave_Receive_IT(&hi2c1, rxBuffer, BUFFER_SIZE);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
HAL_I2C_Slave_Transmit_IT(&hi2c1, txBuffer, BUFFER_SIZE);
HAL_Delay(1000);
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = 16;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 4;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
/* USER CODE BEGIN 4 */
void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *hi2c)
{
if (hi2c->Instance == I2C1)
{
printf("Received: %s\r\n", rxBuffer);
HAL_I2C_Slave_Receive_IT(&hi2c1, rxBuffer, BUFFER_SIZE);
}
}
void HAL_I2C_SlaveTxCpltCallback(I2C_HandleTypeDef *hi2c)
{
if (hi2c->Instance == I2C1)
{
printf("Data Sent: %s\r\n", txBuffer);
}
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
<i2c.c>
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file i2c.c
* @brief This file provides code for the configuration
* of the I2C instances.
******************************************************************************
* @attention
*
* Copyright (c) 2024 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "i2c.h"
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
I2C_HandleTypeDef hi2c1;
/* I2C1 init function */
void MX_I2C1_Init(void)
{
/* USER CODE BEGIN I2C1_Init 0 */
/* USER CODE END I2C1_Init 0 */
/* USER CODE BEGIN I2C1_Init 1 */
/* USER CODE END I2C1_Init 1 */
hi2c1.Instance = I2C1;
hi2c1.Init.ClockSpeed = 400000;
hi2c1.Init.DutyCycle = I2C_DUTYCYCLE_2;
hi2c1.Init.OwnAddress1 = 36;
hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c1.Init.OwnAddress2 = 0;
hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c1) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN I2C1_Init 2 */
if (HAL_I2C_EnableListen_IT(&hi2c1) != HAL_OK)
{
printf("Error enabling listen mode\r\n");
}
/* USER CODE END I2C1_Init 2 */
}
void HAL_I2C_MspInit(I2C_HandleTypeDef* i2cHandle)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(i2cHandle->Instance==I2C1)
{
/* USER CODE BEGIN I2C1_MspInit 0 */
/* USER CODE END I2C1_MspInit 0 */
__HAL_RCC_GPIOB_CLK_ENABLE();
/**I2C1 GPIO Configuration
PB6 ------> I2C1_SCL
PB7 ------> I2C1_SDA
*/
GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF4_I2C1;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* I2C1 clock enable */
__HAL_RCC_I2C1_CLK_ENABLE();
/* I2C1 interrupt Init */
HAL_NVIC_SetPriority(I2C1_EV_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(I2C1_EV_IRQn);
HAL_NVIC_SetPriority(I2C1_ER_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(I2C1_ER_IRQn);
/* USER CODE BEGIN I2C1_MspInit 1 */
/* USER CODE END I2C1_MspInit 1 */
}
}
void HAL_I2C_MspDeInit(I2C_HandleTypeDef* i2cHandle)
{
if(i2cHandle->Instance==I2C1)
{
/* USER CODE BEGIN I2C1_MspDeInit 0 */
/* USER CODE END I2C1_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_I2C1_CLK_DISABLE();
/**I2C1 GPIO Configuration
PB6 ------> I2C1_SCL
PB7 ------> I2C1_SDA
*/
HAL_GPIO_DeInit(GPIOB, GPIO_PIN_6);
HAL_GPIO_DeInit(GPIOB, GPIO_PIN_7);
/* I2C1 interrupt Deinit */
HAL_NVIC_DisableIRQ(I2C1_EV_IRQn);
HAL_NVIC_DisableIRQ(I2C1_ER_IRQn);
/* USER CODE BEGIN I2C1_MspDeInit 1 */
/* USER CODE END I2C1_MspDeInit 1 */
}
}
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
You are mixing hexadecimal notation with decimal, which does not help. 36 is decimal, while in hex it is 0x24.
The addresses of I²C devices (ignoring 10-bit address mode) are 7 bits. However, when you send the address on the I²C bus, you place this address in the 7 most significant bits, and the LSB contains information about the data transfer direction. This is called the R/W bit.
+---------+---------+---------+---------+---------+---------+---------+---------+
| Bit 7 | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
+---------+---------+---------+---------+---------+---------+---------+---------+
| A6 | A5 | A4 | A3 | A2 | A1 | A0 | R/W |
+---------+---------+---------+---------+---------+---------+---------+---------+
R/W Bit values:
0 = Write: The master will write data to the slave device.
1 = Read: The master will read data from the slave device.
So, when you place the address 0x12 in the most significant address bits and want to write, the result is 0x12 << 1, which is 0x24 (or 36 in decimal).
The STM32 HAL libraries expect the device address to have the 7-bit address placed in the most significant bits.