用模拟I2C将其消灭，公布代码

我爱因仑风 · 发表于 2016-5-17 18:39:47

这个模拟I2C的代码也是在本站下载的，原来是访问EEPROM的。

我使用STM32来访问I2C接口的铁电存储器，FM24CL16，2K字节，比访问EEPROM要方便一点，所以简单修改了一下，比原来少很多。

感谢ground网友提供的原始代码！ FM24CL16的手册由于文件服务器问题，暂时传不上来。等阿莫弄好了再传吧。

代码就不打包了，直接贴上来了
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I2C的引脚配置：

/* Configure I2C1 pins: SCL and SDA */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
=================================
/*******************************************************************************
* File Name       : i2c_fram.h
* Author          : MCD Application Team
* Version          : V2.0.1
* Date             : 06/13/2008
* Description       : Header for i2c_ee.c module
*******************************************************************************/
/* Define to prevent recursive inclusion ------------------------------------ */
#ifndef __I2C_FRAM_H
#define __I2C_FRAM_H

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"

/* Exported types ------------------------------------------------------------*/
/* Exported constants --------------------------------------------------------*/

/* Exported macro ------------------------------------------------------------*/
/* Exported functions ------------------------------------------------------- */

bool I2C_FRAM_BufferWrite(u8* pBuffer, u16 WriteAddr, u16 NumByteToWrite);
bool I2C_FRAM_BufferRead(u8* pBuffer, u16 ReadAddr, u16 NumByteToRead);

#endif /* __I2C_FRAM_H */

=================================
/*******************************************************************************
* File Name       : i2c_fram.c
* Author          : Appcat
* Version          : V0.0.1
* Date             : 07/11/2009
* Description       : This file provides a set of functions needed to manage the
*                   communication between I2C peripheral and I2C FM24CL16 FRAM.
*******************************************************************************/

/* Includes ------------------------------------------------------------------*/
#include "i2c_fram.h"

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define I2C_Speed             100000
#define I2C1_SLAVE_ADDRESS7 0xA0
#define I2C_PageSize          256

#define SCL_H       GPIOB->BSRR = GPIO_Pin_6
#define SCL_L       GPIOB->BRR  = GPIO_Pin_6

#define SDA_H       GPIOB->BSRR = GPIO_Pin_7
#define SDA_L       GPIOB->BRR  = GPIO_Pin_7

#define SCL_read    GPIOB->IDR  & GPIO_Pin_6
#define SDA_read    GPIOB->IDR  & GPIO_Pin_7

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
vu8 FRAM_ADDRESS;

/* Private function prototypes -----------------------------------------------*/

/**/
void I2C_delay(void)
{
u8 i=150; //这里可以优化速度       ，经测试最低到5还能写入
while(i)
{
   i--;
}
}

bool I2C_Start(void)
{
      SDA_H;
      SCL_H;
      I2C_delay();
      if(!SDA_read)return FALSE;       //SDA线为低电平则总线忙,退出
      SDA_L;
      I2C_delay();
      if(SDA_read) return FALSE;       //SDA线为高电平则总线出错,退出
      SDA_L;
      I2C_delay();
      return TRUE;
}

void I2C_Stop(void)
{
      SCL_L;
      I2C_delay();
      SDA_L;
      I2C_delay();
      SCL_H;
      I2C_delay();
      SDA_H;
      I2C_delay();
}

void I2C_Ack(void)
{
      SCL_L;
      I2C_delay();
      SDA_L;
      I2C_delay();
      SCL_H;
      I2C_delay();
      SCL_L;
      I2C_delay();
}

void I2C_NoAck(void)
{
      SCL_L;
      I2C_delay();
      SDA_H;
      I2C_delay();
      SCL_H;
      I2C_delay();
      SCL_L;
      I2C_delay();
}

bool I2C_WaitAck(void)       //返回为:=1有ACK,=0无ACK
{
      SCL_L;
      I2C_delay();
      SDA_H;
      I2C_delay();
      SCL_H;
      I2C_delay();
      if(SDA_read)
      {
   SCL_L;
   return FALSE;
      }
      SCL_L;
      return TRUE;
}

void I2C_SendByte(u8 SendByte) //数据从高位到低位//
{
u8 i=8;
while(i--)
{
      SCL_L;
      I2C_delay();
   if(SendByte&0x80)
      SDA_H;
   else
      SDA_L;
      SendByte<<=1;
      I2C_delay();
            SCL_H;
      I2C_delay();
}
SCL_L;
}

u8 I2C_ReceiveByte(void)  //数据从高位到低位//
{
u8 i=8;
u8 ReceiveByte=0;

SDA_H;
while(i--)
{
   ReceiveByte<<=1;
   SCL_L;
   I2C_delay();
      SCL_H;
   I2C_delay();
   if(SDA_read)
   {
      ReceiveByte|=0x01;
   }
}
SCL_L;
return ReceiveByte;
}

bool I2C_FRAM_BufferWrite(u8* pBuffer, u16 WriteAddr, u16 NumByteToWrite)
{
      u8 Addr = 0, count = 0;

      Addr = WriteAddr / I2C_PageSize;

      count = WriteAddr % I2C_PageSize;

      Addr = Addr << 1;

      Addr = Addr & 0x0F;

      FRAM_ADDRESS = I2C1_SLAVE_ADDRESS7 | Addr;

if (!I2C_Start()) return FALSE;
I2C_SendByte(FRAM_ADDRESS);//设置器件地址+段地址
if (!I2C_WaitAck())
      {
            I2C_Stop();
            return FALSE;
      }
I2C_SendByte(count); //设置段内地址
      I2C_WaitAck();

      while(NumByteToWrite--)
      {
      I2C_SendByte(* pBuffer);
      I2C_WaitAck();
   pBuffer++;
      }
      I2C_Stop();
      //注意：因为这里要等待EEPROM写完，可以采用查询或延时方式(10ms)
      //Systick_Delay_1ms(10);
      return TRUE;
}

//读出1串数据
bool I2C_FRAM_BufferRead(u8* pBuffer, u16 WriteAddr, u16 NumByteToRead)
{
      u8 Addr = 0, count = 0;

Addr = WriteAddr / I2C_PageSize;

      count = WriteAddr % I2C_PageSize;

      Addr = Addr << 1;

      Addr = Addr & 0x0F;

      FRAM_ADDRESS = I2C1_SLAVE_ADDRESS7 | Addr;

      if (!I2C_Start()) return FALSE;

I2C_SendByte(FRAM_ADDRESS);//设置器件地址+段地址

if (!I2C_WaitAck())
      {
            I2C_Stop();
            return FALSE;
      }

I2C_SendByte(count); //设置低起始地址
I2C_WaitAck();
I2C_Start();
I2C_SendByte(FRAM_ADDRESS | 0x01);
I2C_WaitAck();
while(NumByteToRead)
{
   *pBuffer = I2C_ReceiveByte();
   if(NumByteToRead == 1)I2C_NoAck();
   else I2C_Ack();
   pBuffer++;
   NumByteToRead--;
}
I2C_Stop();
return TRUE;
}

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