nios i2c 读写数据程序的问题

nios, 数据, 程序

以下是对at89c0808c加密芯片的memory test zone 读写数据的程序，但是有些数据读写正确，有些数据读写就错误，请指点！！

#include"string.h"
#include <stdio.h>
#include "altera_avalon_pio_regs.h"
#include "system.h"
#include "time.h"
#define Set_SDA IOWR_ALTERA_AVALON_PIO_DATA(SDA_BASE, 0x1)
#define Clr_SDA IOWR_ALTERA_AVALON_PIO_DATA(SDA_BASE, 0x0)
#define Set_SCL IOWR_ALTERA_AVALON_PIO_DATA(SCL_BASE, 0x1)
#define Clr_SCL IOWR_ALTERA_AVALON_PIO_DATA(SCL_BASE, 0x0)

void delay1us()
{int a1;
for(a1=0;a1<50;a1++);
}

void delay1ms()
{int a2;
for(a2=0;a2<50000;a2++);
}

void I2C_Start(void)
{
IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
Set_SDA;
Set_SCL;
delay1us();
Clr_SDA;
delay1us();
Clr_SCL;
delay1us();
}

void I2C_Stop(void)
{
IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
Clr_SDA;
Clr_SCL;
delay1us();
Clr_SDA;
Set_SCL;
delay1us();
Set_SDA;
delay1us();
}

void I2C_Ack(void)
{ IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
Clr_SDA;
delay1us();
Set_SCL;
delay1us();
   Clr_SCL;
delay1us();
}

void Check_Ack(void)
{int a=1;
IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x0);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
Clr_SCL;
delay1us();
Set_SCL;
delay1us();
while(a)
   {
     a=IORD_ALTERA_AVALON_PIO_DATA(SDA_BASE);
delay1us();
     printf("waiting ACK .a is %d\n",a);
   }
delay1us();
printf("detected ACK\n");
Clr_SCL;
delay1us();
}

void I2C_Nack(void)
{ IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
Set_SDA;
delay1us();
Set_SCL;
delay1us();
Clr_SCL;
delay1us();
}

void I2C_Send_Byte(int d)
{
int i = 8;
IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
delay1us();
   Clr_SDA;
   Clr_SCL;
delay1us();

while( i-- )
{

    if (d&0x80)
        Set_SDA;
    else
        Clr_SDA;
delay1us();

       Set_SCL;
delay1us();
       Clr_SCL;
delay1us();
      Clr_SDA;
      Clr_SCL;
delay1us();

    d = d << 1;
   }
delay1us();
}

int I2C_Receive_Byte(void)
{ int retc,bitcnt;
           retc=0;
IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x0);
IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1);
delay1us();


    for(bitcnt=0;bitcnt<8;bitcnt++)
    {      Set_SCL;
      delay1ms();
       retc=retc<<1;
   if((int)IORD_ALTERA_AVALON_PIO_DATA(SDA_BASE)) retc=retc+1;

        Clr_SCL;

delay1ms();


    }


    return(retc);
}

int main()
{int data[500]={0}; int cnt;

I2C_Start();
I2C_Send_Byte(0xb4);
Check_Ack();
I2C_Send_Byte(0x00);
Check_Ack();
I2C_Send_Byte(0x0a);
Check_Ack();
I2C_Send_Byte(0x02);
Check_Ack();
I2C_Send_Byte(0x39);
Check_Ack();
I2C_Send_Byte(0x8d);
Check_Ack();
I2C_Stop();
delay1ms();

I2C_Start();
I2C_Send_Byte(0xb6);
Check_Ack();
I2C_Send_Byte(0x00);
Check_Ack();
I2C_Send_Byte(0x0a);
Check_Ack();
I2C_Send_Byte(0x02);
Check_Ack();
for(cnt=0;cnt<2;cnt++)
{data[cnt]=I2C_Receive_Byte();
printf("data=%x\n",data[cnt]);
I2C_Ack();
}
data[cnt+1]=I2C_Receive_Byte();
printf("data=%x\n",data[cnt+1]);
I2C_Nack();
I2C_Stop();

}