读AT24C08时, 频繁开机出现读出数据不正确. 请高手花费时间看一下啊!
写时可以均可以.看看程序有没能问题啊?
这和刚开机时,主机时钟稳定有关吧?
/* =========================================================
* 函 数 名: vvoid I2Cm_SetPinOUT(void)
* 功能描述: 设置数据口为输触
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
void I2Cm_SetPinOUT(void)
{
/11*****************************/
I2CDATADDR_OUT;
I2CDATAOR_OUT; }
/* =========================================================
* 函 数 名: void I2Cm_SetPinIn(void)
* 功能描述: 设置数据口为输入
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
void I2Cm_SetPinIn(void)
{
I2CDATADDR_IN;
I2CDATAOR_IN;
}
/* =========================================================
* 函 数 名: void I2Cm_Start(void)
* 功能描述: 开始
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
void I2Cm_Start(void)
{
I2C_CLK = 1;
I2C_DATA = 1;
I2Cm_SetPinOUT();
I2C_DATA = 0;
I2C_CLK = 0;
}
/* =========================================================
* 函 数 名: void I2Cm_Stop(void)
* 功能描述: 开始
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
void I2Cm_Stop(void)
{
I2C_DATA = 0;
I2Cm_SetPinOUT();
I2C_CLK = 1;
I2C_DATA = 1;
}
/* =========================================================
* 函 数 名:unsigned char I2Cm_CheckBusy(void)
* 功能描述: 检测忙否
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
void I2Cm_Reset(void)
{
unsigned char i;
for (i = 0; i < 20; i++)
{
I2C_CLK = 0;
I2C_CLK = 1;
}
I2Cm_Start();
I2C_DATA = 1;
I2Cm_SetPinOUT();
I2Cm_SetPinIn();
I2C_CLK = 1;
}
/* =========================================================
* 函 数 名:unsigned char I2Cm_CheckBusy(void)
* 功能描述: 检测忙否 true 为不忙 false 为忙
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
unsigned char I2Cm_CheckBusy(void)
{
unsigned char nEEPCycleCount; // EEP一次写入计数器,防止死循环
nEEPCycleCount = 0;
I2C_CLK = 0;
do
{
I2C_DATA = 1;
I2Cm_SetPinOUT();
I2Cm_SetPinIn();
I2C_CLK = 1;
nEEPCycleCount++;
if (nEEPCycleCount > 50)
I2Cm_Reset(); // 复位
if (nEEPCycleCount > 100)
return false;
}while (!I2C_DATA); // 检测应答位是否正确
return true;
}
/* =========================================================
* 函 数 名: unsigned char I2Cm_TxByte (unsigned char I2c_TxData)
* 功能描述: 发送一个字节
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
unsigned char I2Cm_TxByte (unsigned char I2c_TxData)
{
unsigned char i, j;
unsigned char nEEPCycleCount; //EEP一次写入计数器,防止死循环
nEEPCycleCount = 0;
do
{
f_MCU_FeedDog();
if (nEEPCycleCount)
I2Cm_Start();
I2Cm_SetPinOUT();
for (i = 0; i < 8; i++)
{
I2C_CLK = 0;
j = 1 << (7 - i);
if (I2c_TxData & j)
I2C_DATA = 1;
else
I2C_DATA = 0;
I2C_CLK = 1;
}
I2C_CLK = 0;
I2Cm_SetPinIn();
I2C_CLK = 1;
nEEPCycleCount++; //Prevent From Dead Cycle
if (nEEPCycleCount > 20)
return false;
}while (I2C_DATA); //检测应答位是否正确
I2C_CLK = 0;
return true;
}
/* =========================================================
* 函 数 名: unsigned char I2Cm_RxByte(void)
* 功能描述: 读入一个字节
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
unsigned char I2Cm_RxByte(void)
{
unsigned char i, nValue = 0;
f_MCU_FeedDog();
I2Cm_SetPinIn();
for (i = 0; i < 8; i++)
{
I2C_CLK = 0; //时钟为低
Nop();
Nop();
I2C_CLK = 1; //时钟为高
nValue <<= 1;
if(!I2C_DATA)
nValue |= 0;
else
nValue |= 1;
}
I2C_CLK = 0; //时钟为低
I2Cm_Stop(); //结束位
return nValue;
}
/* =========================================================
* 函 数 名: unsigned char I2Cm_Read(unsigned char I2c_Address)
* 功能描述: 读数据
* 调用方法:
* 输入变量:
* 输出变量:
========================================================= */
//unsigned char I2Cm_Read(unsigned char I2c_Address) rzm-- 8.12
int I2Cm_Read(unsigned char I2c_Address)
{
if(I2Cm_CheckBusy() == false)
// return false;
return -1;
I2Cm_Start();
if(I2Cm_TxByte(0xa0) == false)
// return false;
return -1;
if(I2Cm_TxByte(I2c_Address) == false)
// return false;
return -1;
I2Cm_Start();
if(I2Cm_TxByte(0xa1) == false)
// return false;
return -1;
return I2Cm_RxByte();
}
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