0904_BOOT/BSP/iic2.c

#include "iic2.h"
#include "delay.h"
#include "includes.h"

void iic2_init(void)
{
	rcu_periph_clock_enable(RCU_GPIOB);//使能GPIOB时钟
	rcu_periph_clock_enable(RCU_GPIOE);

	//IIC时钟信号位
	gpio_init(IIC2_SCL_PORT,GPIO_MODE_OUT_OD,GPIO_OSPEED_50MHZ,IIC2_SCL_PIN);
	gpio_bit_set(IIC2_SCL_PORT,IIC2_SCL_PIN);

	//IIC数据信号位
	gpio_init(IIC2_SDA_PORT,GPIO_MODE_OUT_OD,GPIO_OSPEED_50MHZ,IIC2_SDA_PIN);
	gpio_bit_set(IIC2_SDA_PORT,IIC2_SDA_PIN);
}

//产生IIC起始信号
void IIC2_Start(void)
{
	IIC2_SDA_OUT();
    IIC2_SDA(1);//IIC_SDA = 1;
    IIC2_SCL(1);//IIC_SCL = 1;
    delay_us(4);
    IIC2_SDA(0);//IIC_SDA = 0;//START:when CLK is high,DATA change form high to low
    delay_us(4);
    IIC2_SCL(0);//IIC_SCL = 0;//钳住I2C总线，准备发送或接收数据
}


//产生IIC停止信号
void IIC2_Stop(void)
{
	IIC2_SDA_OUT();
    IIC2_SDA(0);//IIC_SDA = 0;
    IIC2_SCL(0);//IIC_SCL = 0;
    delay_us(4);
    IIC2_SCL(1);//IIC_SCL = 1;
    IIC2_SDA(1);//IIC_SDA = 1;
    delay_us(4);
}
//等待应答信号到来
//返回值：
//		1，接收应答失败
//    0，接收应答成功
u8 IIC2_Wait_Ack(void)
{
	uint8_t ucErrTime=0;
    IIC2_SDA_IN();  // SDA 配置成输入
    IIC2_SDA(1);//IIC_SDA=1;
    delay_us(1);
    IIC2_SCL(1);//IIC_SCL=1;
    delay_us(1);
    while(IIC2_READ_SDA)
    {
        ucErrTime++;
        if(ucErrTime>250)
        {
        IIC2_Stop();
        return 1;
        }
    }
    IIC2_SCL(0);//IIC_SCL=0;
    return 0;
  
}
//产生ACK应答
void IIC2_Ack(void)
{
	IIC2_SCL(0);//IIC_SCL = 0;
    IIC2_SDA_OUT();
    IIC2_SDA(0);//IIC_SDA = 0;
    delay_us(4);
    IIC2_SCL(1);//IIC_SCL = 1;
    delay_us(2);
    IIC2_SCL(0);//IIC_SCL = 0;
}
//不产生ACK应答
void IIC2_NAck(void)
{
	IIC2_SCL(0);//IIC_SCL = 0;
    IIC2_SDA_OUT();
    IIC2_SDA(1);//IIC_SDA = 1;
    delay_us(4);
    IIC2_SCL(1);//IIC_SCL = 1;
    delay_us(2);
    IIC2_SCL(0);//IIC_SCL = 0;
}
//IIC发送一个字节
//返回从机有无应答
//1，有应答
//0，无应答
void IIC2_Send_Byte(u8 txd)
{                    

	uint8_t t;
	IIC2_SCL(0);//IIC_SCL=0;// 电平置低，开始传输数据
	IIC2_SDA_OUT();
	for(t=0;t<8;t++)
	{
		// IIC_SDA=(txd&0x80)>>7;
		if((txd&0x80)>>7) IIC2_SDA(1);
		else IIC2_SDA(0);
		txd<<=1;
		delay_us(4);   //
		IIC2_SCL(1);//IIC_SCL=1;
		delay_us(2);
		IIC2_SCL(0);//IIC_SCL=0;
		delay_us(2);
	}
}
//读1个字节，ack=1时，发送ACK，ack=0，发送nACK
u8 IIC2_Read_Byte(u8 ack)
{
	uint8_t i,receive=0;
    IIC2_SDA_IN();//SDA设置为输入
    for(i=0;i<8;i++ )
    {
        IIC2_SCL(0);//IIC_SCL=0;
        delay_us(4);
        IIC2_SCL(1);//IIC_SCL=1;
        receive<<=1;
        if(IIC2_READ_SDA)receive++;
        delay_us(1);
    }
    if(!ack)
        IIC2_NAck();//发送nACK
    else
        IIC2_Ack(); //发送ACK
    return receive;
}

//////////////////////////////////////////////////////////////////////////////////
void Tmp75_read(u8 *pBuffer)
{

	u16 lentow;
	lentow = 2;
	
	IIC2_Start();

	IIC2_Send_Byte(0x90);//写
	IIC2_Wait_Ack();

	IIC2_Send_Byte(0x00);   //发送寄存器地址
	IIC2_Wait_Ack();

	delay_us(4);
	IIC2_Start();
	IIC2_Send_Byte(0x91);  //读       //进入接收模式
	IIC2_Wait_Ack();

	while(lentow)
	{
		*pBuffer=IIC2_Read_Byte(1);
		pBuffer++;
		//ReadAddr++;
		lentow--;
	}
	IIC2_Stop();//产生一个停止条件
}

u8 Temp_buf[4];
float Temp_test(void)
{
	float temp_data,tmp;
	
	iic2_init();
	
	Tmp75_read(Temp_buf);
	//data_dump("temp Read", Temp_buf, 2);
//	printf("\ntemp Read ");
//	printf("%d ",Temp_buf[0]);
//	printf("%d \n",Temp_buf[1]);
	
	tmp = (float)(Temp_buf[1]>>4);
	tmp /= 16.0;
	temp_data = (float)Temp_buf[0] + tmp;
//	printf("\ntemp Read: ");
//	printf("%f\n",temp_data);
	return temp_data;
}