stm32 Nucleo-L011K4 i2c acknowledgement failure - c

Question

I am trying to read accelerometer data over i2c. The i2c address of the accelerometer is 0x19 for reading and 0x18 for writing. To check for correct communication with the accelerometer, I should read register 0x00 and it must return 0x12 as the result. But I am not able to get acknowledgement from the accelerometer. I am using the HAL libraries and code generated using CubeMX. Here is the code:
#include "main.h"
#include "stm32l0xx_hal.h"
I2C_HandleTypeDef hi2c1;
void SystemClock_Config(void);
void Error_Handler(void);
static void MX_GPIO_Init(void);
static void MX_I2C1_Init(void);
uint8_t data[2];
uint8_t result;
int main(void)
{
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_I2C1_Init();
while (1)
{
// HAL_I2C_Mem_Read_DMA(I2C_HandleTypeDef *hi2c, uint16_t DevAddress, uint16_t MemAddress, uint16_t MemAddSize, uint8_t *pData, uint16_t Size)
HAL_I2C_Mem_Read_DMA(&hi2c1, 0x19, 0x00, 1, &result, 1);
HAL_Delay(100);
}
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInit;
/**Configure the main internal regulator output voltage */
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/**Initializes the CPU, AHB and APB busses clocks */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
RCC_OscInitStruct.MSIState = RCC_MSI_ON;
RCC_OscInitStruct.MSICalibrationValue = 0;
RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_5;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/**Initializes the CPU, AHB and APB busses clocks */
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_I2C1;
PeriphClkInit.I2c1ClockSelection = RCC_I2C1CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
/**Configure the Systick interrupt time */
HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
/**Configure the Systick */
HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
/* SysTick_IRQn interrupt configuration */
HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}
/* I2C1 init function */
static void MX_I2C1_Init(void)
{
hi2c1.Instance = I2C1;
hi2c1.Init.Timing = 0x00000708;
hi2c1.Init.OwnAddress1 = 0x18;
hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c1.Init.OwnAddress2 = 0;
hi2c1.Init.OwnAddress2Masks = I2C_OA2_NOMASK;
hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c1) != HAL_OK)
{
Error_Handler();
}
/**Configure Analogue filter */
if (HAL_I2CEx_ConfigAnalogFilter(&hi2c1, I2C_ANALOGFILTER_ENABLE) != HAL_OK)
{
Error_Handler();
}
}
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
}
2 external pull up resistors of 4,7kOhms are used.
mc pins:
https://developer.mbed.org/platforms/ST-Nucleo-L011K4/
pins D4 and D5 to SDA and SCL respectively. GND and 3.3V are connected to accelerometers respective power connections.

Answer 1

The SDA pin of board is PB7 and SCL pin is PB6. However, you don't initialize these pins clock. You should enable port B clock in MX_GPIO_Init function.
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
}
You should set OwnAddress1 to 0 in MX_I2C1_Init function.
hi2c1.Init.OwnAddress1 = 0;
Also read address should be 0x18 in HAL_I2C_Mem_Read_DMA or HAL_I2C_Mem_Read function. I am not sure Timing is correct. Most of I2C devices clock speed is between 100-400Khz. What is your I2C device clock speed? You can try at 100 or 400Khz.
hi2c1.Init.Timing = 400000;