STM32 learning path: basic reading and writing of I2C

Macro definition:

/*I2C transmission speed, up to 400kHz*/

#define I2C_SPEED 400000

/* The I2C address of the STM32 itself. This address only needs to be different from the I2C device address of the STM32 external device*/

#define I2C_OWN_ADDR 0x77

/*EEPROM address*/

#define EEPROM_ADDR (0x50<<1) //0xA0

#define EEPROM_SCL_GPIO_CLK RCC_AHB1Periph_GPIOB

#define EEPROM_SCL_PIN GPIO_Pin_6

#define EEPROM_SCL_GPIO_PORT GPIOB

#define EEPROM_SCL_AF GPIO_AF_I2C1

#define EEPROM_SCL_SOURCE GPIO_PinSource6

#define EEPROM_SDA_GPIO_CLK RCC_AHB1Periph_GPIOB

#define EEPROM_SDA_PIN GPIO_Pin_7

#define EEPROM_SDA_GPIO_PORT GPIOB

#define EEPROM_SDA_AF GPIO_AF_I2C1

#define EEPROM_SDA_SOURCE GPIO_PinSource7

#define EEPROM_I2C_CLK RCC_APB1Periph_I2C1

#define EEPROM_I2C I2C1

/*================1-Initialize EEPROM_GPIO port (refer to USART for multiplexed pin function)==========================*/

void EEPROM_GPIO_Config(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

RCC_AHB1PeriphClockCmd(EEPROM_SCL_GPIO_CLK|EEPROM_SDA_GPIO_CLK,ENABLE);

/* GPIO initialization */

/* Push-pull output/pull-up resistor/50M output speed*/

  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;  

  GPIO_InitStructure.GPIO_Speed ​​= GPIO_Speed_50MHz;

/* Configure the SCL pin as an alternate function */

/* Select alternate function mode/select SCL pin*/

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

        GPIO_InitStructure.GPIO_Pin = EEPROM_SCL_PIN;  

  GPIO_Init(EEPROM_SDA_GPIO_PORT, &GPIO_InitStructure);

  /* Configure the SDA pin as an alternate function*/

 /* Select alternate function mode/select SDA pin*/

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = EEPROM_SDA_PIN;

  GPIO_Init(EEPROM_SCL_GPIO_PORT, &GPIO_InitStructure);

/* Connect PXx to EEPROM_SCL*/

  GPIO_PinAFConfig(EEPROM_SCL_GPIO_PORT,EEPROM_SCL_SOURCE,EEPROM_SCL_AF);

  /* Connect PXx to EEPROM_SDA*/

  GPIO_PinAFConfig(EEPROM_SDA_GPIO_PORT,EEPROM_SDA_SOURCE,EEPROM_SDA_AF);

}

/*================2-Initialize IIC mode==============================================*/

/*

I2C Structure

ClockSpeed: Set the I2C transmission rate

Requirements: less than 400kHz

Mode: I2C usage mode

I2C_Mode_I2C : I2C normal mode

I2C Master and Slave Mode

I2C_Mode_SMBusDevice

I2C_Mode_SMBusHost

DutyCycle: sets the duty cycle of the I2C SCL line clock

I2C_DutyCycle_16_9 Duty cycle 16:9

I2C_DutyCycle_2 Duty cycle 2:1

OwnAddress1: STM32's I2C device's own address

Ack: I2C response enable setting

I2C_Ack_Enable: Enable

I2C_Ack_Disable: Disable

AcknowledgedAddress: I2C addressing mode

I2C_AcknowledgedAddress_7bit 7-bit addressing

I2C_AcknowledgedAddress_10bit 10-bit addressing

/*

void EEPROM_I2C_ModeConfig(void)

{

/* Define I2C structure declaration*/

I2C_InitTypeDef I2C_InitStruct;

/* Turn on the peripheral I2C clock */

RCC_APB1PeriphClockCmd(EEPROM_I2C_CLK,ENABLE);

/* I2C transfer rate */

I2C_InitStruct.I2C_ClockSpeed ​​= I2C_SPEED;

/* I2C mode */

I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;

/* Duty cycle */

I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;

/* I2C address itself */

I2C_InitStruct.I2C_OwnAddress1 = I2C_OWN_ADDR;

/* Promise to enable */

I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;

/* Addressing mode */

I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

/* Initialize I2C */

I2C_Init(EEPROM_I2C,&I2C_InitStruct);

  /* Enable I2C */

  I2C_Cmd(EEPROM_I2C,ENABLE);

}

/*==============3-Write a byte function==================================================*/

void EEPROM_Byte_Write(uint8_t* pData,uint8_t addr)

{

/* Start signal */

  I2C_GenerateSTART(EEPROM_I2C,ENABLE);

/* Detect EV5 event, used after the start signal*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_MODE_SELECT) != SUCCESS )

  {

     //....

  }

/* Send EEPROM address */

  I2C_Send7bitAddress(EEPROM_I2C,EEPROM_ADDR,I2C_Direction_Transmitter);

  /* Detect EV6 event, used after slave address*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED) != SUCCESS )

  {

  }

  /* Send storage address, that is, EEPROM internal address*/

  I2C_SendData(EEPROM_I2C,addr);

  /* Detect EV8 event, used to transmit data*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_BYTE_TRANSMITTED) != SUCCESS )

  {

  }

  /* send data*/

  I2C_SendData(EEPROM_I2C,*pData);

  /* Detect EV8 events */

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_BYTE_TRANSMITTED) != SUCCESS )

  {

  }

  /* Stop signal */

  I2C_GenerateSTOP(EEPROM_I2C,ENABLE);

}

/*==============4-Read a byte function===================================================*/

uint8_t EEPROM_Byte_Read(uint8_t addr)

{

  uint8_t readTemp;

  /* Wait for EEPROM internal writing to complete*/

  Wait_for_EEPROM();

  /* Start signal */

  I2C_GenerateSTART(EEPROM_I2C,ENABLE);

  /* Detect EV5 event, used after the start signal*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_MODE_SELECT) != SUCCESS )

  {

     //....

  }

  /* Send EEPROM address */

  I2C_Send7bitAddress(EEPROM_I2C,EEPROM_ADDR,I2C_Direction_Transmitter);

  /* Detect EV6 event, used after slave address*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED) != SUCCESS )

  {

  }

  /* Send the EEPROM internal address of the read data*/

  I2C_SendData(EEPROM_I2C,addr);

  /* Detect EV8_2 event*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_BYTE_TRANSMITTED) != SUCCESS )

  {

  }

  /* Start signal */

  I2C_GenerateSTART(EEPROM_I2C,ENABLE);

  /* Detect EV5 event, used after the start signal*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_MODE_SELECT) != SUCCESS )

  {

     //....

  }

  /* Send EEPROM address */

  I2C_Send7bitAddress(EEPROM_I2C,EEPROM_ADDR,I2C_Direction_Receiver);

  /* Detect EV6 event, used after slave address*/

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED) != SUCCESS )

  {

  }

  /*Terminate enable response*/

  I2C_AcknowledgeConfig(EEPROM_I2C,DISABLE);

  /* Detect EV7 event */

  while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_BYTE_RECEIVED) != SUCCESS )

  {

  }

  /* Read received data */

  readTemp = I2C_ReceiveData(EEPROM_I2C);

  /* Stop signal */

  I2C_GenerateSTOP(EEPROM_I2C,ENABLE);

  return readTemp;

}

/*==============5-Waiting for EEPROM to finish writing (I don't quite understand the details)====================================================*/

void Wait_for_EEPROM(void)

{

  do

  {

    I2C_GenerateSTART(EEPROM_I2C,ENABLE);

// while(I2C_CheckEvent(EEPROM_I2C,I2C_EVENT_MASTER_MODE_SELECT) != SUCCESS )

// {

// //....

// }

    I2C_Send7bitAddress(EEPROM_I2C,EEPROM_ADDR,I2C_Direction_Transmitter);  

  }while(I2C_GetFlagStatus(EEPROM_I2C,I2C_FLAG_ADDR) == RESET);

  //Wait for ADDR = 1 before executing the following statement

  I2C_ClearFlag(EEPROM_I2C,I2C_FLAG_AF);

  I2C_GenerateSTOP(EEPROM_I2C,ENABLE);

  while(I2C_GetFlagStatus(EEPROM_I2C,I2C_FLAG_BUSY) == SET);

  //The bus is idle, execute the following statement

}