关于MSP430与AT24C02的问题

只看该作者 · 2015-4-6 22:08

调了几天的存储芯片24C02，感觉程序上没有什么问题啊。可是程序总是卡在ACK（）中的while里。不知道什么原因。望有经验的大神帮忙解决下。不胜感激。
#include "msp430x26x.h"

#define uchar unsigned char
#define uint  unsigned int

#define TRUE  1
#define FALSE 0

#define CPU_F ((double)16000000)
#define delay_us(x) __delay_cycles((long)(CPU_F*(double)x/1000000.0))
#define delay_ms(x) __delay_cycles((long)(CPU_F*(double)x/1000.0))

#define SDA_H P4OUT |=BIT5
#define SDA_L P4OUT &=~BIT5
#define SCL_H P4OUT |=BIT6
#define SCL_L P4OUT &=~BIT6
#define SDA_TRUE  P4IN&BIT5

#define SDA_IN  P4DIR &=~BIT5
#define SDA_OUT P4DIR |=BIT5

void AT24C02_Init()       //初始化，需将时钟线和数据线拉高
{
  P4DIR |=BIT5+BIT6;          //AT24C02 SDA SCL
  SDA_H;
  SCL_H;
}
void AT24C02_START()       //起始条件，SCL高电平时候，SDA的一个下降沿
{
  SDA_OUT;
  SDA_H;
  delay_us(10);
  SCL_H;
  delay_us(10);
  SDA_L;
  delay_us(10);
  SCL_L;
}
void AT24C02_STOP()    //停止条件，SCL高电平时候，SDA的一个上升沿
{
  SDA_OUT;
  SDA_L;
  delay_us(7);
  SCL_H;
  delay_us(7);
  SDA_H;
  delay_us(7);
}

void ACK()
{
  //unsigned char i=0;
  SDA_H;
  delay_us(10);
  SCL_H;
  delay_us(10);
  SDA_IN;
  //while(SDA_TRUE&&(i<255)) i++;
  while(SDA_TRUE);
  SCL_L;
  delay_us(10);
  SDA_OUT;
}
void AT24C02_send_char(unsigned char data)  //IIC协议要求从高位开始传送，传送1字节
{
  unsigned char i=0;
  SDA_OUT;
  SCL_L;                                  //此时，SCL被拉低,才允许SDA变化
  SDA_H;
  delay_us(5);
  for(i=0;i<8;i++)
  {
if(data&(0x80>>i))
   SDA_H;
else
   SDA_L;
SCL_H;                      //拉高SCL,不允许SDA变化
delay_us(10);
SCL_L;
delay_us(10);                //拉低SCL,开始下1bit传送
  }

  SDA_H;                      //释放数据线
  delay_us(5);
}

unsigned char AT24C02_receive_char()
{
//SCL低电平 SDA高电平
  unsigned char temp=0,i=0;
  SCL_L;
  SDA_H;
  SDA_IN;
  for(i=0;i<8;i++)
  {
SCL_H;
delay_ms(3);
if(SDA_TRUE)
   temp=temp|(0x80>>i);
SCL_L;
delay_ms(2);
  }
  SDA_OUT;
  return temp;
}

void AT24C02_write_byte(unsigned char address,unsigned char data)
{
  AT24C02_START();
  AT24C02_send_char(0xa0);
  ACK();
  AT24C02_send_char(address);
  ACK();
  AT24C02_send_char(data);
  ACK();
  AT24C02_STOP();
}
unsigned char AT24C02_read_byte(unsigned char address)
{
  unsigned val=0;
  AT24C02_START();
  AT24C02_send_char(0xa0);
  ACK();
  AT24C02_send_char(address);
  ACK();
  AT24C02_START();
  AT24C02_send_char(0xa1);
  ACK();
  val=AT24C02_receive_char();
  AT24C02_STOP();
  return val;
}

void main()
{
  unsigned char r=0;
  WDTCTL =WDTPW+WDTHOLD;                               //停止开门狗
  CLK_Init();
  AT24C02_Init();

  AT24C02_write_byte(0x10,0x12);
  Delay_ms(5);
  r=AT24C02_read_byte(0x10);

  while(1);
}