AT24C256不返回ACK

maosongbai

AT24C256不返回ACK [复制链接]

我用的AT24C256 EEPROM，经常在写入第二个字节的地址后，它就不返回ACK，导致读取数据失败。大部分时间返回正常，有时候不返回ACK，不产生IIC中断。请问这是什么原因？

wdwcymwjy

是不是时序不对？
我刚搞定AT24C256 EEPROM读写问题， MCU是新华龙的C8051F020

fastlin

你是怎么读写的？我的就是在写入地址后转入读模式的时候，经常会死掉，就是不产生IIC中断了

liushupi

我的处理器是S3C2440，自己根据例子写个IIC中断处理程序，结果老出问题

andrewlzj

[code]void IRQ_I2C(void)
{

int i;

#if OS_CRITICAL_METHOD == 3                               /* Allocate storage for CPU status register */
   OS_CPU_SR  cpu_sr;
#endif
OS_ENTER_CRITICAL();

i2cint = 0;

iicSt = rIICSTAT;

if(iicSt & 0x8){
I2C_end = 0xFF;
rIICCON = 0xaf;
ClearPending(BIT_IIC);
return;
}          //When bus arbitration is failed.clear pending bit
if(iicSt & 0x4){ClearPending(BIT_IIC);}          //When a slave address is matched with IICADD
if(iicSt & 0x2){ClearPending(BIT_IIC);}          //When a slave address is 0000000b

if(iicSt & 0x1){
if(I2C_num >0 ){
rIICSTAT = iicSt&(~(1<<5));
rIICCON  = 0x2f;
Delay(1);
//OSSemPost(I2cFail);
ClearPending(BIT_IIC);
return;
}          //When ACK isn't received and iic data hasn't transmitted over
}

switch(_iicMode)
{
   case POLLACK:

         i2stat = iicSt; //-- return the status register value
//          OSSemPost(I2cSucc);
           i2cint = 1;/////////---
           i2cnum = I2C_num;
         break;

   case RDDATA:
   I2C_num--;
   if(I2C_num == -1){
   rIICSTAT = 0x90;                  //Stop MasRx condition
   //rIICCON  = 0xaf;                  //Resumes IIC operation.
      rIICCON  = 0x2f;
   Delay(1);                         //Wait until stop condtion is in effect.
      i2cint = 2; ///---
                  i2cnum = I2C_num;
               OSSemPost(I2cSucc);
   break;
   }
   *pI2C_buf++ = rIICDS;
   if(I2C_num==0){ //no data to be send
      rIICCON = 0x2f; //Resumes IIC operation with NOACK.
   i2cint = 3;///---
              i2cnum = I2C_num;
   }else{
            rIICCON = 0xaf;                //Resumes IIC operation with ACK
               i2cint = 4;///---
            i2cnum = I2C_num;
         }
         break;
      case WRDATA:
        if(I2C_suba_en ==0){ //-- two word address both transmitted
            if((I2C_num--)==0){
                  rIICSTAT = 0xd0;          //Stop MasTx condition
                  rIICCON  = 0xaf;          //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
                  Delay(1);                //Wait until stop condtion is in effect.
                    //The pending bit will not be set after issuing stop condition.
                  I2C_end = TRUE;
                  OSSemPost(I2cSucc);
                          i2cint = 5;///---
                          i2cnum = I2C_num;
                  break;
            }else{
            rIICDS = *pI2C_buf++;
            //for(i=0;i<10;i++);
            rIICCON = 0xaf; //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
            i2cint = 6;///---
            i2cnum = I2C_num;
            break;
            }
         }
        if(I2C_suba_en ==4){ //-- writer mode:write first word address
            rIICDS = I2C_subaH;
            //for(i=0;i<10;i++); //-- for setup time until rising edge of IICSCL
            rIICCON = 0xaf; //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
            I2C_suba_en--; //-- I2C_suba_en = 2,indicate that first word address has been transmitted.
            i2cint = 7;///---
            i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==3){ //-- write second word address
            rIICDS = I2C_subaL;
            // for(i=0;i<10;i++);
            rIICCON = 0xaf; //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
            I2C_suba_en = 0; //-- second word address transmitted,I2C_suba_en ==0
               i2cint = 8;///---
               i2cnum = I2C_num;
            break;
         }
   case SETRDADDR:
         if(I2C_suba_en ==2){ //--to read data,first ,write word address to EEPROM
            rIICDS = I2C_subaH;
            //for(i=0;i<10;i++); //-- for setup time until rising edge of IICSCL
            Delay(1);
            rIICCON = 0xaf; //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
            I2C_suba_en--; //-- I2C_suba_en = 2,indicate that first word address has been transmitted.
               i2cint = 9;///---
               i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==1){ //-- ??????????word???????·
            rIICDS = I2C_subaL;
            //for(i=0;i<10;i++); //-- for setup time until rising edge of IICSCL
            rIICCON = 0xaf; //-- writer 0 to IICCON[4] to clear the int pend,resuming IIC operation (this also assert the ack enable and rx/tx int enable)
            I2C_suba_en = 0; //-- I2C_suba_en = 2,indicate that first word address has been transmitted.
               i2cint = 10;///---
               i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==0){ //-- read mode:two 8-bit word addressess write completed
rIICDS    = I2C_sla+1;
rIICSTAT = 0xb0;            //MasRx,Start
rIICCON = 0xaf;            //Resumes IIC operation.
I2C_suba_en = -1;
            i2cint = 11;///---
            i2cnum = I2C_num;
            break;
}
if(I2C_suba_en == -1){ //-- read mode:two 8-bit word addressess write completed
_iicMode = RDDATA; //-- set iic operation mode flag to read
rIICCON = 0xaf;            //Resumes IIC operation with ACK.
               i2cint = 12;///---
               i2cnum = I2C_num;
            break;
}
      default:
        rIICCON  = 0x2f;
        i2cint = 14;///---
        i2cnum = I2C_num;
         break;
}
//================================
ClearPending(BIT_IIC);
//================================
OS_EXIT_CRITICAL();
}

katrina

能否把你的电路，和程序写出来啊，这么说太浅显了，还有，听楼主的介绍，是用的单片机内部I2C总线吧？是不是哪些设置不正确呢？

明枫

void IRQ_I2C(void)
{

int i;

#if OS_CRITICAL_METHOD == 3
   OS_CPU_SR  cpu_sr;
#endif
OS_ENTER_CRITICAL();

i2cint = 0;

iicSt = rIICSTAT;

if(iicSt & 0x8){
I2C_end = 0xFF;
rIICCON = 0xaf;
ClearPending(BIT_IIC);
return;
}          //When bus arbitration is failed.clear pending bit
if(iicSt & 0x4){ClearPending(BIT_IIC);}          //When a slave address is matched with IICADD
if(iicSt & 0x2){ClearPending(BIT_IIC);}          //When a slave address is 0000000b

if(iicSt & 0x1){//-- 没有收到返回
if(I2C_num >0 ){
rIICSTAT = iicSt&(~(1<<5));
rIICCON  = 0x2f;
Delay(1);
//OSSemPost(I2cFail);
ClearPending(BIT_IIC);
return;
}          //When ACK isn't received and iic data hasn't transmitted over
}

switch(_iicMode)
{
   case POLLACK:

         i2stat = iicSt; //-- return the status register value
//          OSSemPost(I2cSucc);
           i2cint = 1;/////////---
           i2cnum = I2C_num;
         break;

   case RDDATA:// 读操作
   I2C_num--;
   if(I2C_num == -1){
   rIICSTAT = 0x90;                  //Stop MasRx condition
   //rIICCON  = 0xaf;
            rIICCON  = 0x2f;
   Delay(1);
            i2cint = 2;
                  i2cnum = I2C_num;
               OSSemPost(I2cSucc);
   break;
   }
   *pI2C_buf++ = rIICDS;
   if(I2C_num==0){
      rIICCON = 0x2f; //Resumes IIC operation with NOACK.
   i2cint = 3;///---
              i2cnum = I2C_num;
   }else{
            rIICCON = 0xaf;                         //Resumes IIC operation with ACK
               i2cint = 4;///---
            i2cnum = I2C_num;
         }
         break;
      case WRDATA://写操作
        if(I2C_suba_en ==0){ //-- 两个字节的地址都写入了
            if((I2C_num--)==0){
                  rIICSTAT = 0xd0;          //Stop MasTx condition
                  rIICCON  = 0xaf;          //-- resume iic
                  Delay(1);                //Wait until stop condtion is in effect.

                  I2C_end = TRUE;
                  OSSemPost(I2cSucc);
                          i2cint = 5;///---
                          i2cnum = I2C_num;
                  break;
            }else{
            rIICDS = *pI2C_buf++;
            //for(i=0;i<10;i++);
            rIICCON = 0xaf; //-- resume iic
            i2cint = 6;///---
            i2cnum = I2C_num;
            break;
            }
         }
        if(I2C_suba_en ==4){ //-- 先写入第一个字节的地址
            rIICDS = I2C_subaH;
            //for(i=0;i<10;i++); //-- for setup time

until rising edge of IICSCL
            rIICCON = 0xaf; //-- resume iic
            I2C_suba_en--; //-- 已写入第一个字节地址
            i2cint = 7;///---
            i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==3){ //-- 再写第二字节地址
            rIICDS = I2C_subaL;
            // for(i=0;i<10;i++);
            rIICCON = 0xaf; //-- resume iic
            I2C_suba_en = 0; //-- 两个字节地址都写完了，让I2C_suba_en ==0
               i2cint = 8;///---
               i2cnum = I2C_num;
            break;
         }
   case SETRDADDR:// 读数据前，设置地址
         if(I2C_suba_en ==2){ //--读数据前，先写入地址，现在写入高地址
            rIICDS = I2C_subaH;
            //for(i=0;i<10;i++);
            Delay(1);
            rIICCON = 0xaf; //-- resume iic
            I2C_suba_en--;
               i2cint = 9;
               i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==1){ //-- 写入低地址
            rIICDS = I2C_subaL;
            //for(i=0;i<10;i++);
            rIICCON = 0xaf; //-- resume iic
            I2C_suba_en = 0;
               i2cint = 10;
               i2cnum = I2C_num;
            break;
         }
         if(I2C_suba_en ==0){ //-- 两个字节地址都写入了
rIICDS    = I2C_sla+1;
rIICSTAT = 0xb0;            //发送重新起始条件，转到读模式
rIICCON = 0xaf;       //Resumes IIC operation.
I2C_suba_en = -1;
            i2cint = 11;///---
            i2cnum = I2C_num;
            break;
}
if(I2C_suba_en == -1){ //-- EEPROM对读起始条件的ACK
_iicMode = RDDATA; //-- set iic operation mode flag to read
rIICCON = 0xaf;       //Resumes IIC operation with ACK.
               i2cint = 12;///---
               i2cnum = I2C_num;
            break;
}
      default:
        rIICCON  = 0x2f;
        i2cint = 14;///---
        i2cnum = I2C_num;
         break;
}
//================================
ClearPending(BIT_IIC);
//================================
OS_EXIT_CRITICAL();
}

duibuqi

这是读函数：
[code]
uint8 IRcvStr(uint8 subaL,uint8 subaH,uint8 *s,uint8 no)
{
    uint8 err;
   _iicMode = SETRDADDR; //-- first,use write mode to write word address

I2C_sla = AT24C256;            //AT24C256 0Xa0

   I2C_subaH = subaH;

   I2C_subaL = subaL;

   pI2C_buf = s;

   I2C_num = no;

   I2C_suba_en = 2;

   I2C_end = 0;

rIICDS = I2C_sla;                //0xa0,//-- first,write slave address
rIICCON = 0xaf;
ClearPending(BIT_IIC);

rIICSTAT = 0xf0;                   //MasTx,Start

OSSemPend(I2cSucc,600,&err);
Delay(5);
if(err == OS_NO_ERR) return 1;
else return 0;

}

d123123

我是这样测试的：没隔5s，就读EEPROM 1320个字节，一般在读个十几次后，EEPROM就不回ACK了。

vairkey

2440的I2C用的硬件控制的？速度设多少？

xyw

是不是读的太快了,每读一页延时一下看看

lisheng053758

要不就别要ACK了，只要能读出来，了事。。。

我在操作2401的时候就这么干的

神的召唤啊

引用 9 楼 shuiyan 的回复:
2440的I2C用的硬件控制的？速度设多少？

S3C2440有IIC的时钟控制器，只能设置两个值，我选择了其中一个值，应该没问题

c51rf2

还没弄好吗？

cranes_u

EEPROM 要求的时序有没有严格实行？问题的关键哦

shunv424

暂时不搞了，将就着用

flyaround

我建议你用模拟的IIC来做，简单的多了

AT24C256不返回ACK [复制链接]

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