STM32F1 模拟I2C驱动DAC(LTC2605)程序

由于在电路设计上将SCL、SDA线拉太长导致硬件I2C时常出问题，所以考虑用模拟I2C解决，这里参考别人的代码然后自己应用到24位DAC(LTC2605)上，已移植成功。

(1).simulate_i2c.c

#include "stm32f10x.h"
#include "simulate_i2c.h"

#define HIGH 1
#define LOW 0

#define TRUE 1
#define FALSE 0

#define Master_Address 0x0A
#define WR 0X00
#define RD 0X01

#define SCL_H GPIO_SetBits(GPIOB,GPIO_Pin_6)
#define SCL_L GPIO_ResetBits(GPIOB,GPIO_Pin_6)
#define SDA_H GPIO_SetBits(GPIOB,GPIO_Pin_7)
#define SDA_L GPIO_ResetBits(GPIOB,GPIO_Pin_7)

void delay_us(u16 time)
{
u16 i = 0;
while(time--)
{
i = 10;
while(i--);
}
}

void I2C_INIT(void)
{
   GPIO_InitTypeDef GPIO_Init_Structure;
   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
   GPIO_Init_Structure.GPIO_Pin = GPIO_Pin_6;
   GPIO_Init_Structure.GPIO_Mode = GPIO_Mode_Out_OD;
   GPIO_Init_Structure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_Init(GPIOB,&GPIO_Init_Structure);
   GPIO_SetBits(GPIOB,GPIO_Pin_6);
}

void SDA_OUT(){
   GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //????
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;       //IO????50MHz
GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void SDA_IN(){
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //????,?????????????
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //IO????50MHz
GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void I2C_Start(void)
{
   SDA_OUT();

   SDA_H;
   SCL_H;

delay_us(5);

   SDA_L;
   delay_us(5);

   SCL_L;
}

void I2C_Stop(void)
{
   SDA_OUT();

   SCL_L;

   SDA_L;

    delay_us(5);

   SCL_H;

   SDA_H;
   delay_us(5);
}

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u8 I2C_Wait_Ack(void)
{
   u8 ucErrTime = 0;
   SDA_H;
delay_us(5);

       SDA_IN();

       SCL_H;
delay_us(5);

       while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7))
       {
           ucErrTime++;
           if(ucErrTime > 250)
           {
               return FALSE;
           }
       }

       SCL_L;

return TRUE;
}

void I2C_Ack(void)
{

   SCL_L;

   SDA_OUT();

   SDA_L;

   delay_us(5);

   SCL_H;

   delay_us(5);

   SCL_L;

}

void I2C_NAck(void)
{
   SCL_L;
   SDA_OUT();

   SDA_H;
   delay_us(5);

   SCL_H;
   delay_us(5);

   SCL_L;
}

void I2C_Send_Byte(u8 txd)
{
u8 t;

       SDA_OUT();

       SCL_L;
for(t = 0; t < 8; t++)
{
       if((txd&0x80) >> 7)
           SDA_H;
       else
           SDA_L;

       txd <<= 1;

       delay_us(5);

       SCL_H;

       delay_us(5);

       SCL_L;

       delay_us(5);
}
}

u8 I2C_Read_Byte(void)
{
   unsigned char i, receive = 0;

   SDA_IN();

for(i = 0; i < 8; i++ )
   {

           SCL_L;
           delay_us(5);

       SCL_L;

           receive = (receive << 1) | GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7);

       delay_us(5);
}

   return receive;
}

u8 Write_Temp_Value(u16 temp_input)
{
u8 Data[2];
Data[0]= temp_input&0x00ff;
Data[1]= (temp_input>>8)&0x00ff;

   I2C_Start();

   I2C_Send_Byte(0x20);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(0x22);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(Data[1]);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(Data[0]);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Stop();
   return 0;
}


u8 Write_Pre_In(u16 pre_In_input)
{
   u8 Data[2];
   Data[0]= pre_In_input&0x00ff;
Data[1]= (pre_In_input>>8)&0x00ff;

   I2C_Start();

   I2C_Send_Byte(0x20);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(0x21);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(Data[1]);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(Data[0]);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Stop();
   return 0;
}

u8 Write_Pre_Out(u16 pre_Out_input)
{
   u8 Data[2];
   Data[0]= pre_Out_input&0x00ff;
Data[1]= (pre_Out_input>>8)&0x00ff;

   I2C_Start();

   I2C_Send_Byte(0x20);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

   I2C_Send_Byte(0x20);
   if(!I2C_Wait_Ack()){
       I2C_Stop();
       return 0;
   }

(2). simulate_i2c.h

#ifndef __SIMULATE_I2C_H__
#define __SIMULATE_I2C_H__

#include "stm32f10x.h"

void delay_us(u16 time);
void I2C_INIT(void);
void SDA_OUT();
void SDA_IN();
void I2C_Start(void);
void I2C_Stop(void);
u8 I2C_Wait_Ack(void);
void I2C_Ack(void);
void I2C_NAck(void);
void I2C_Send_Byte(u8 txd);
u8 I2C_Read_Byte(void);
u8 Write_Temp_Value(u16 temp_input);
u8 Write_Pre_In(u16 pre_In_input);
u8 Write_Pre_Out(u16 pre_Out_input);

#endif /* __I2C_DRIVE_MCP_H */

(3). main.c

int main(void){

I2C_INIT();

Write_Temp_Value(65535);

}

STM32F1 模拟I2C驱动DAC(LTC2605)程序

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