Connection of an accelerometer MMA8452Q to the correspondent STM32 peripheral

Posted on November 17, 2016 at 21:02

I have some issues with the STM32 code for Connection of an accelerometer MMA8452Q to the correspondent STM32 peripheral I2C communication.

What is missing?

#include ''stm32f10x.h''

#include ''lcd.h''

#include ''stdio.h''

volatile u8 X, Y, Z;

void usart_config(){

void RCC_Config_HSE_PLL_Max()

{

RCC_DeInit();

RCC_HSEConfig(RCC_HSE_ON);

ErrorStatus HSEStartUpStatus;

HSEStartUpStatus = RCC_WaitForHSEStartUp();

if(HSEStartUpStatus == SUCCESS)

{

FLASH_SetLatency(FLASH_Latency_2);

FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

RCC_HCLKConfig(RCC_SYSCLK_Div1);

RCC_PCLK1Config(RCC_HCLK_Div1);

RCC_PCLK2Config(RCC_HCLK_Div1);

RCC_PLLConfig(RCC_PLLSource_HSE_Div2, RCC_PLLMul_12);

RCC_PLLCmd(ENABLE);

while( RCC_GetFlagStatus( RCC_FLAG_PLLRDY ) == RESET );

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

while(RCC_GetSYSCLKSource() != 0x08);

}

else

while(1);

}

//configuration of the LED

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

//USART configuration

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

USART_InitTypeDef USART_InitStructure;

//default baudrate - 9600

USART_InitStructure.USART_BaudRate = 9600;

//databits - 8

USART_InitStructure.USART_WordLength = USART_WordLength_8b;

//stopbits - 1

USART_InitStructure.USART_StopBits = USART_StopBits_1;

//odd parity

USART_InitStructure.USART_Parity = USART_Parity_Odd;

//no hardware flowcontrol

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

//both receiving and transmitting mode

USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;

USART_Init(USART2, &USART_InitStructure);

USART_Cmd(USART2, ENABLE);

//USART interruption configuration

NVIC_InitTypeDef NVIC_InitStructure;

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

}

void i2cconfig()

{

    GPIO_InitTypeDef  GPIO_InitStructure;

    I2C_InitTypeDef  I2C_InitStructure;

    /*enable I2C*/

    I2C_Cmd(I2C2,ENABLE);

    /* I2C2 clock enable */

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);

    // I2C2 SDA and SCL configuration, SCL is pin11 and SDA is pin 12 for I2C2

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;

    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;

    GPIO_Init(GPIOB, &GPIO_InitStructure);

   I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

    I2C_InitStructure.I2C_ClockSpeed = 500000;

    I2C_InitStructure.I2C_OwnAddress1 = 0;

    I2C_Init(I2C2, &I2C_InitStructure);

    I2C_Cmd(I2C2, ENABLE);

}

void I2C_receiver_one()

{

I2C_GenerateSTART(I2C2, ENABLE); //Start condition to start communicating with the slave

while(!(I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT)));

I2C_Send7bitAddress(I2C2, 0x1D, I2C_Direction_Transmitter);

 while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

I2C_SendData(I2C2,0x2A);

while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

I2C_GenerateSTART(I2C2, ENABLE); //Start condition to start communicating with the slave

while(!(I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT)));

I2C_Send7bitAddress(I2C2, 0x1D, I2C_Direction_Receiver);

    // Test Receive mode Flag

    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_RECEIVED));

  X = I2C_ReceiveData(I2C2);

  I2C_AcknowledgeConfig(I2C2, DISABLE);

I2C_GenerateSTOP(I2C2, ENABLE);

while(I2C_GetFlagStatus(I2C2, I2C_FLAG_STOPF)); // stop bit flag

}

int main(void)

{

RCC_Config_HSE_PLL_Max();

lcd_init ();

i2cconfig();

usart_config();

I2C_receiver_one();

while(1)

   {

   }

}

And the handler:

extern X;

extern Y;

extern Z;

void USART2_IRQHandler(void)

{

//variables for the received data and for the switch status

volatile uint8_t RxData;

//if it is receiving

if(USART_GetITStatus(USART2, USART_IT_RXNE)== SET)

{

// while it is still receiving data do....

while( USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET );

//attribution of the received data to the rxdata variable

    RxData = USART_ReceiveData(USART2);

  if (RxData=='a')

  {

  GPIO_SetBits(GPIOA,GPIO_Pin_2);

  //u8 X, Y, Z;

  char buffer1 [10];

  char buffer2 [10];

  char buffer3 [10];

  sprintf(buffer1,''X = %d'', X);

  sprintf(buffer2,''Y = %d'', Y);

  sprintf(buffer3,''Z = %d'', Z);

lcd_draw_string(5,20,buffer1,1000,1);

  lcd_draw_string(5,60,buffer2,1000,1);

    lcd_draw_string(5,100,buffer3,1000,1);

    while( USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET );

    RxData = USART_ReceiveData(USART2);

    USART_ClearFlag(USART2,USART_FLAG_RXNE);

    }

USART_ClearFlag(USART2,USART_FLAG_RXNE);

USART_ClearITPendingBit(USART2, USART_IT_RXNE);

}

}