Software simulation of I2C (based on the Microchip 24LC16B operation function library)

This article uses software-simulated I2C to implement a function library for operating 24LC16B on the STM8L15x series chips.

Header file definition:

 #ifndef _24LC16B_H

#define _24LC16B_H

#include "Hal_I2CSoft.h"

#define MAXROM_24LC16B (2048)

extern void Hal24LC16BInit(I2CSoftConfig_t* i2cCfg);

extern u8 Hal24LC16B_ReadByte(u16 addr);

extern void Hal24LC16B_WriteByte(u16 addr, u8 data);

extern void Hal24LC16B_ReadBuf(u16 addr, u8 *buf, u16 len);

extern void Hal24LC16B_WriteBuf(u16 addr, u8 *buf, u16 len);

extern void Hal24L68B_WritePage(u16 addr, u8 *buf);

 #endif

Specific operation function:

/**

  ******************************************************************************

  * @f file 24LC16B.c

  * @Author huangqi

  * @Version V1.0.0

  * @Date 2014-12-20

  * @Description Microchip's 24LC16B operation function library

  ******************************************************************************

  */

#include "Hal_I2CSoft.h"

#include "24LC16B.h"

I2CSoftConfig_t *i2cCfg;

/********************************************************************************

 * @Function name Hal24LC16BInit

 *

 * @Function Initialize 24LC16B

 *

 * @parameter i2cCfg: I2CSoft port information

 *

 * @return value None

 *********************************************************************************/

void Hal24LC16BInit(I2CSoftConfig_t* i2cPortConfig)

{

  i2cCfg = i2cPortConfig;

  I2CSoft_Init(i2cCfg);

}

/********************************************************************************

 * @Function name Hal24LC16B_ReadByte

 *

 * @Function Read a byte from 24LC16B

 *

 * @param addr: address

 *

 * @return value The bytes read

 *********************************************************************************/

u8 Hal24LC16B_ReadByte(u16 addr)

{

  u8 tmp = 0;

  do

  {

    I2CSoft_Start(i2cCfg);

    I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1));//write command

  }

  while(I2CSoft_WaitAck(i2cCfg));

  I2CSoft_SendByte(i2cCfg, addr%256);

  I2CSoft_WaitAck(i2cCfg);

  I2CSoft_Start(i2cCfg);

  I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1)+1); //write command

  I2CSoft_WaitAck(i2cCfg);

  tmp = I2CSoft_RecvByte(i2cCfg,0);

  I2CSoft_Stop(i2cCfg);

  return tmp;

}

/********************************************************************************

 * @Function name Hal24LC16B_WriteByte

 *

 * @Function Write a byte to 24LC16B

 *

 * @param addr: address

 * data: data to be written

 *

 * @return value None

 *********************************************************************************/

void Hal24LC16B_WriteByte(u16 addr, u8 data)

{

  do

  {

    I2CSoft_Start(i2cCfg);

    I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1));//write command

  }

  while(I2CSoft_WaitAck(i2cCfg));

  I2CSoft_SendByte(i2cCfg, addr%256);

  I2CSoft_WaitAck(i2cCfg);

  I2CSoft_SendByte(i2cCfg, data); //write command

  I2CSoft_WaitAck(i2cCfg);

  I2CSoft_Stop(i2cCfg);

  //delay_us(3000);//Must wait for EEPROM writing to complete

}

/********************************************************************************

 * @Function name Hal24LC16B_WriteByte

 *

 * @Function Write a page to 24LC16B (16Byte in total)

 *

 * @param addr: address

 * data: data to be written

 *

 * @return value None

 *********************************************************************************/

void Hal24L68B_WritePage(u16 addr, u8 *buf)

{

  u8 cnt=16;

  if((addr+16)%256<16)

    return;

  do

  {

    I2CSoft_Start(i2cCfg);

    I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1));//write command

  }

  while(I2CSoft_WaitAck(i2cCfg));

  I2CSoft_SendByte(i2cCfg, addr%256);

  I2CSoft_WaitAck(i2cCfg);

  while(cnt--)

  {

    I2CSoft_SendByte(i2cCfg, *buf++); //write command

    I2CSoft_WaitAck(i2cCfg);

  }

  I2CSoft_Stop(i2cCfg);

  //delay_us(3000);//Must wait for EEPROM writing to complete

}

/********************************************************************************

 * @Function name Hal24LC16B_ReadBuf

 *

 * @Function Read data from 24LC16B

 *

 * @param addr: address

 * buf: read data

 * len: the length of the data to be read

 *

 * @return value None

 *********************************************************************************/

void Hal24LC16B_ReadBuf(u16 addr, u8 *buf, u16 len)

{

  u16 i = 0;

  if((len>0)&&(addr+len)>=(MAXROM_24LC16B-1))

    return;

  do

  {

    I2CSoft_Start(i2cCfg);

    I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1));//write command

  }

  while(I2CSoft_WaitAck(i2cCfg));

  I2CSoft_SendByte(i2cCfg, addr%256);

  I2CSoft_WaitAck(i2cCfg);

  I2CSoft_Start(i2cCfg);

  I2CSoft_SendByte(i2cCfg, 0xA0+((addr/256)<<1)+1); //write command

  I2CSoft_WaitAck(i2cCfg);

  for(i = 0; i  {

    *buf++ = I2CSoft_RecvByte(i2cCfg,1);

  }

  *buf = I2CSoft_RecvByte(i2cCfg,0);

  I2CSoft_Stop(i2cCfg);

}

/********************************************************************************

 * @Function name Hal24LC16B_WriteBuf

 *

 * @Function Write data to 24LC16B

 *

 * @param addr: address

 * buf: data to be written

 * len: length of the data to be written

 *

 * @return value None

 *********************************************************************************/

void Hal24LC16B_WriteBuf(u16 addr, u8* buf, u16 len)

{

  u16 i;

  if((len>0)&&(addr+len)>=(MAXROM_24LC16B-1))

    return;

  for(i=0; i  {

    Hal24LC16B_WriteByte(addr++,*buf++);

  }

}

I2C software simulation driver:

head File:

#ifndef _HAL_I2CSOFT_H

#define _HAL_I2CSOFT_H

#include "stm8l15x.h"

typedef struct I2CSoftConfig_t

{

  GPIO_TypeDef* SCL_Port;

  GPIO_Pin_TypeDef SCL_Pin;

  GPIO_TypeDef* SDA_Port;

  GPIO_Pin_TypeDef SDA_Pin;

}I2CSoftConfig_t;

//extern void delay_us(u16 time);

extern void I2CSoft_Init(I2CSoftConfig_t* i2cConfg);

extern void I2CSoft_Start(I2CSoftConfig_t *i2cPortConfig);

extern void I2CSoft_Stop(I2CSoftConfig_t *i2cPortConfig);

extern u8 I2CSoft_WaitAck(I2CSoftConfig_t *i2cPortConfig);

extern void I2CSoft_SendByte(I2CSoftConfig_t *i2cPortConfig, u8 sendByte);

extern u8 I2CSoft_RecvByte(I2CSoftConfig_t *i2cPortConfig, u8 ack);

#endif

I2C protocol implementation:

/**

  ******************************************************************************

  * @f file hal_Flash.c

  * @Author huangqi

  * @Version V1.0.0

  * @Date 2014-12-23

  * @description Simulate I2C related operations

  ******************************************************************************

  */

#include "Hal_I2CSoft.h"

void delay_us(u32 us)

{

    for( u32 x=us;x>0;x-- )

    {

      nop();nop();nop();nop();

    }

}

void I2CSoft_Init(I2CSoftConfig_t* i2cPortConfig)

{

  GPIO_Init(i2cPortConfig->SCL_Port,i2cPortConfig->SCL_Pin,GPIO_Mode_Out_PP_Low_Slow);//GPIO_Mode_Out_OD_Low_Slow);

  GPIO_Init(i2cPortConfig->SDA_Port,i2cPortConfig->SDA_Pin,GPIO_Mode_Out_OD_Low_Slow);//GPIO_Mode_Out_OD_Low_Slow);

}

void I2CSoft_Start(I2CSoftConfig_t* i2cPortConfig)

{

// i2cPortConfig->SDA_Port->DDR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

  delay_us(2);

  i2cPortConfig->SDA_Port->ODR &= ~i2cPortConfig->SDA_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

}

void I2CSoft_Stop(I2CSoftConfig_t* i2cPortConfig)

{

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

// i2cPortConfig->SDA_Port->DDR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SDA_Port->ODR &= ~i2cPortConfig->SDA_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

  i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin;

  delay_us(2);

}

u8 I2CSoft_WaitAck(I2CSoftConfig_t* i2cPortConfig)

{

  u8 ucErrTime;

// i2cPortConfig->SDA_Port->DDR &= ~i2cPortConfig->SDA_Pin;

  i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin; //Open-drain output turns off NMOS and uses it as input

  //delay_us(2);

  i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

  delay_us(2);

  while(i2cPortConfig->SDA_Port->IDR & i2cPortConfig->SDA_Pin)

  {

    ucErrTime++;

    if(ucErrTime>250)

    {

      I2CSoft_Stop(i2cPortConfig);

      return 1;

    }

  }

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

//delay_us(2);

  return 0;

}

static void I2CSoft_Ack(I2CSoftConfig_t* i2cPortConfig)

{

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

//i2cPortConfig->SDA_Port->DDR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SDA_Port->ODR &= ~i2cPortConfig->SDA_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

}

static void I2CSoft_NoAck(I2CSoftConfig_t* i2cPortConfig)

{

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

// i2cPortConfig->SDA_Port->DDR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

  delay_us(2);

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

}

void I2CSoft_SendByte(I2CSoftConfig_t* i2cPortConfig, u8 sendByte)

{

  u8 i=8;

// i2cPortConfig->SDA_Port->DDR |= i2cPortConfig->SDA_Pin;

  i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

  delay_us(2);

  while(i--)

  {

    if(sendByte&(1<    {

      i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin;

    }

    else

    {

      i2cPortConfig->SDA_Port->ODR &= ~i2cPortConfig->SDA_Pin;

    }

    delay_us(2);

    i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;

    delay_us(2);

    i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

  }

  delay_us(2);

 // return I2C_RecvACK();

}

//Read 1 byte, when ack=1, send ACK, when ack=0, send nACK

u8 I2CSoft_RecvByte(I2CSoftConfig_t* i2cPortConfig, u8 ack)

{

  u8 i=8,recvByte=0;

  i2cPortConfig->SDA_Port->ODR |= i2cPortConfig->SDA_Pin; //SDA is set as input

// i2cPortConfig->SDA_Port->DDR &= ~i2cPortConfig->SDA_Pin;

  while(i--)

  {

    i2cPortConfig->SCL_Port->ODR &= ~i2cPortConfig->SCL_Pin;

    delay_us(2);

    i2cPortConfig->SCL_Port->ODR |= i2cPortConfig->SCL_Pin;