请大佬赐教一下关于MCP3421芯片的问题 -

#ifndef __MCP_H
#define __MCP_H
#include "sys.h"
#define IIC_SCL_PORT GPIOB
#define IIC_SCL_CLK RCC_APB2Periph_GPIOB
#define IIC_SCL_PIN GPIO_Pin_6
#define IIC_SDA_PORT GPIOB
#define IIC_SDA_CLK RCC_APB2Periph_GPIOB
#define IIC_SDA_PIN GPIO_Pin_7
#define MCP3421_12AD 0x80
#define MCP3421_14AD 0x84
#define MCP3421_16AD 0x88
#define MCP3421_18AD 0x8c
//IO方向设置
#define SDA_IN() {GPIOB->CRL&=0X0FFFFFFF;GPIOB->CRL|=8<<8;}
#define SDA_OUT() {GPIOB->CRL&=0X0FFFFFFF;GPIOB->CRL|=3<<8;}
//IO操作函数
#define Set_IIC_SCL {GPIO_SetBits(IIC_SCL_PORT,IIC_SCL_PIN);}
#define Clr_IIC_SCL {GPIO_ResetBits(IIC_SCL_PORT,IIC_SCL_PIN);}
#define Set_IIC_SDA {GPIO_SetBits(IIC_SDA_PORT,IIC_SDA_PIN);}
#define Clr_IIC_SDA {GPIO_ResetBits(IIC_SDA_PORT,IIC_SDA_PIN);}
#define READ_SDA (GPIO_ReadInputDataBit(IIC_SDA_PORT, IIC_SDA_PIN))
//IIC所有操作函数
void IIC_Init(void); //初始化IIC的IO口
void IIC_Start(void); //发送IIC开始信号
void IIC_Stop(void); //发送IIC停止信号
void IIC_Send_Byte(u8 txd); //IIC发送一个字节
u8 IIC_Read_Byte(void);//IIC读取一个字节
u8 IIC_Wait_Ack(void); //IIC等待ACK信号
void IIC_Ack(void); //IIC发送ACK信号
void IIC_NAck(void); //IIC不发送ACK信号
float READ_MCP3421(void);
void WRITE_MCP3421(unsigned char wr_data);
u32 Read_Mcp3421_Data(void);
void IIC_Write_One_Byte(u8 daddr,u8 addr,u8 data);
u8 IIC_Read_One_Byte(u8 daddr,u8 addr);
u32 Get_Adc(void);
extern unsigned long int elech;
extern unsigned long int elecl;
extern unsigned long int elecm;
extern unsigned long int mcp_busy;
void IIC_Delay(void);
void IIC_Start_Test(void);
#endif

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#include "mcp.h"
void IIC_Delay(void)
{
unsigned int i;
for(i=0;i<75;i++)
{
}
}
void IIC_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);
GPIO_InitStructure.GPIO_Pin = IIC_SCL_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; //推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(IIC_SCL_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = IIC_SDA_PIN;
GPIO_Init(IIC_SDA_PORT, &GPIO_InitStructure);
Set_IIC_SCL;
Set_IIC_SDA;
}
//产生IIC起始信号
void IIC_Start(void)
{
SDA_OUT(); //sda线输出
Set_IIC_SDA;
Set_IIC_SCL;
IIC_Delay();
Clr_IIC_SDA;//START:when CLK is high,DATA change form high to low
IIC_Delay();
Clr_IIC_SCL;//钳住I2C总线，准备发送或接收数据
}
//产生IIC停止信号
void IIC_Stop(void)
{
SDA_OUT();//sda线输出
Clr_IIC_SCL;
Clr_IIC_SDA;//STOP:when CLK is high DATA change form low to high
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
Set_IIC_SDA;//发送I2C总线结束信号
IIC_Delay();
}
//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 IIC_Wait_Ack(void)
{
unsigned char i=2;
SDA_IN(); //SDA设置为输入
Set_IIC_SDA;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
while(i--)
{
if(READ_SDA==1)
{
Clr_IIC_SCL;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
}
else
goto loop;
}
loop:
Clr_IIC_SCL;
IIC_Delay();
return 0;
}
//产生ACK应答
void IIC_Ack(void)
{
Clr_IIC_SCL;
SDA_OUT();
Clr_IIC_SDA;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
Clr_IIC_SCL;
}
//不产生ACK应答
void IIC_NAck(void)
{
Clr_IIC_SCL;
SDA_OUT();
Set_IIC_SDA;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
Clr_IIC_SCL;
}
//IIC发送一个字节
//返回从机有无应答
//1，有应答
//0，无应答
void IIC_Send_Byte(u8 txd)
{
u8 t;
SDA_OUT();
for(t=0;t<8;t++)
{
Clr_IIC_SCL;
IIC_Delay();
if (txd&0x80) Set_IIC_SDA
else Clr_IIC_SDA;
txd<<=1;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
}
Clr_IIC_SCL;
}
//读1个字节，ack=1时，发送ACK，ack=0，发送nACK
u8 IIC_Read_Byte(void)
{
unsigned char i,receive=0;
SDA_IN();//SDA设置为输入
for(i=0;i<8;i++ )
{
receive<<=1;
Clr_IIC_SCL;
IIC_Delay();
Set_IIC_SCL;
IIC_Delay();
if(READ_SDA)
{
receive |= 0x01;
}
else
{
receive &= 0xfe;
}
}
Clr_IIC_SCL;
return receive;
}
/*******************************************************************
wr_data:MCP3421_12AD 采用12位AD
wr_data:MCP3421_14AD 采用14位AD
wr_data:MCP3421_16AD 采用16位AD
wr_data:MCP3421_18AD 采用18位AD
********************************************************************/
void WRITE_MCP3421(unsigned char wr_data)
{
IIC_Start();
IIC_Send_Byte(0xd0);//写
IIC_Wait_Ack();
IIC_Send_Byte(wr_data);
IIC_Wait_Ack();
IIC_Stop();
}
float READ_MCP3421(void)
{
unsigned long int elech;
unsigned long int elecm;
unsigned long int elecl;
unsigned long int AD_B_Result;
float AD_F_Result=0.0;
IIC_Start();
IIC_Send_Byte(0xd1);//读
IIC_Wait_Ack();
elech=(long int)IIC_Read_Byte();
IIC_Ack();
elecm=(long int)IIC_Read_Byte();
IIC_Ack();
elecl=(long int)IIC_Read_Byte();
IIC_NAck();
IIC_Stop();
AD_B_Result=(elech<<16)|(elecm<<8)|(elecl);
AD_B_Result=AD_B_Result&0x01ffffff;
AD_F_Result=(float)((float)(2.048/131072)*((float)AD_B_Result));
return AD_F_Result;
}

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int main(void)
{
float Vrm = 0.0;
char DisBuf[200];
IIC_Init();
while(1)
{
WRITE_MCP3421(MCP3421_18AD);
Vrm=READ_MCP3421();
IIC_Delay();
printf(" | V:%4.2f | \r\n",Vrm);
sprintf(DisBuf,"% 4.2f",Vrm);
LCD_ShowString(110,270, (u8*)DisBuf,DARKBLUE);
}
}

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