|
|
马老师，这是我用ATMEGA32的TWI接口写的一个读写PCF8563的程序，本来昨天是可以正确收到从机状态码0x18的，但是今天为什么我发了从机地址后，TWCC值会被修改，并且不会产生TWINT中断呢？
//I2c definition
#define I2cError 0x01
#define I2cStart() TWCR = ( 1<<TWINT ) | ( 1<<TWSTA ) | ( 1<<TWEN ) //send start condition
#define I2cStop() TWCR = ( 1<<TWINT ) | ( 1<<TWEN ) | ( 1<<TWSTO ) //trasmit stop condition
#define ClearTWINT() TWCR = ( 1<<TWINT ) | ( 1<<TWEN ) //clear TWINT in TWCR to start transmit
#define WaitTWINT() while( !( TWCR & ( 1<<TWINT ) ) )
#define CheckI2cStatus() ( TWSR & 0XF8 )
//define I2c status word
#define START 0x08
#define MT_SLA_ACK 0x18
#define MT_SLA_NACK 0x20
#define MT_DATA_ACK 0x28
#define MT_DATA_NACK 0x30
#define MR_SLA_ACK 0X40
#define MR_DATA_ACK 0X50
/************************************************************************/
//Rtc functions list
//MCU Write to I2c slaver
//Mcu Transmit As Master
unsigned char WriteRtc( unsigned char SlaAddr, unsigned char RegAddr, unsigned char *SlaData, unsigned char Length )
{
unsigned char i;
I2cStart();
WaitTWINT(); //wait for TWINT set , caused by start signal
if( CheckI2cStatus() != START )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
TWDR = SlaAddr; //TWDR must be written when TWINT set
ClearTWINT();
WaitTWINT(); //wait for TWINT come, that indicates transmit ok
if( CheckI2cStatus() != MT_SLA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
TWDR = RegAddr;
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MT_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
for( i = 0; i < Length; )
{
static unsigned char WriteErrorCount;
TWDR = *( SlaData+i );
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MT_DATA_ACK )
{
if( WriteErrorCount++ >20 )
{
I2cStop();
break;
}
FlagError |= I2cError;
continue;
}
i++;
}
I2cStop();
FlagError &= ( I2cError ^ 0xff );
return( FlagError );
}
//MCU Read from I2c slaver
//Mcu Receive As Master
unsigned char ReadRtc( void )
{
unsigned char Minute, Hour, Day, Week, Month, Year;
I2cStart();
WaitTWINT();
if( CheckI2cStatus() != START )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
TWDR = ReadPcf8563; //send slave address
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_SLA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
TWDR = SecondAddr; //send register of device
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
I2cStop();
TWDR = ReadPcf8563;
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_SLA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff2[6] = TWDR; //read second
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
Minute = TWDR; //read Minute
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff2[2] = AnodeSeg[( Minute&0x0f )]; //low byte of Minute
DisBuff2[3] = AnodeSeg[( Minute>>4 )]; //high byte of Minute
Hour = TWDR; //read Hour
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff2[4] = AnodeSeg[Hour&0x0f]; //low byte of beijing hour
DisBuff2[5] = AnodeSeg[( Hour>>4 )]; //high byte of beijing hour
Day = TWDR; //read Day
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff1[4] = AnodeSeg[( Day>>4 )]; //high byte of day
DisBuff1[5] = AnodeSeg[( Day&0x0f )]; //low byte of day
Week = TWDR; //read week
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff1[11] = AnodeSeg[( ( 1>>Week )^0xff )]; //week
Month = TWDR; //read Month
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff1[2] = AnodeSeg[( Month>>4 )]; //high byte of month
DisBuff1[3] = AnodeSeg[( Month&0x0f )]; //low byte of month
Year = TWDR; //read Year
ClearTWINT();
WaitTWINT();
if( CheckI2cStatus() != MR_DATA_ACK )
{
FlagError |= I2cError;
I2cStop();
return( FlagError );
}
DisBuff1[0] = AnodeSeg[( Year>>4 )]; //high byte of year
DisBuff1[1] = AnodeSeg[( Year&0x0f)]; //low byte of year
I2cStop();
FlagError &= ( I2cError ^ 0xff );
return( FlagError );
} |
阿莫论坛20周年了！感谢大家的支持与爱护！！
曾经有一段真挚的爱情摆在我的面前，我没有珍惜，现在想起来，还好我没有珍惜……
|
发表于 2008-4-28 16:46:24
楼主