Question

我是PIC的新手。我知道这个论坛上有很多关于I2C的帖子，我已经尝试了所有给出的方法，但仍然没有解决我的问题。我使用pic16f1516和外部EEPROM CAT24C04TDI来存储一些数据。我使用了4k7欧姆电阻来上拉，我的代码是：

void I2CWrite(void); 
void WaitMSSP(void);
void I2CRead(void);
void i2c_init(void);
//void _delay_ms(unsigned int);
void main()
{ 
_delay_ms(100); // Give delay for power up
i2c_init(); // Initialize I2C
_delay_ms(20); 
I2CWrite(); // Sends the data to I2C EEPROM
_delay_ms(50);
while(1)
{
I2CRead(); // Read back the data?s
TXREG='\n';
while(TXIF==0); 
TXREG='\r'; 
_delay_ms(500);
}
} 
void I2CWrite()
{
SSPCON2bits.SEN=1;
WaitMSSP(); // wait for the operation to be finished
SSPBUF=0xa0;//Send Slave address write command
WaitMSSP();
SSPBUF=0x00; // Send the starting address to write
WaitMSSP(); 
SSPBUF=0x34; // rough data to be written
WaitMSSP();
}
PEN=1; // Send stop bit
WaitMSSP(); 
}
void I2CRead()
{
SEN=1; //Send start bit
WaitMSSP(); //wait for the operation to be finished
SSPBUF=0xa0;//Send Slave address write command
WaitMSSP(); 
SSPBUF=0x00; // Send the starting address to write
WaitMSSP(); 
RSEN=1; // Send re-start bit
WaitMSSP();
SSPBUF=0xa1; // Slave address read command
WaitMSSP();
RCEN=1; // Enable receive
WaitMSSP(); 
ACKDT=1; // Acknowledge data 1: NACK, 0: ACK
ACKEN=1; // Enable ACK to send
PEN=1; // Stop condition
WaitMSSP();
putch(SSPBUF); // Send the received data to PC
_delay_ms(30); 
}
PEN=1;
WaitMSSP();
}
void WaitMSSP()
{
while(!SSPIF); // while SSPIF=0 stay here else exit the loop
SSPIF=0; // operation completed clear the flag
}
void i2c_init()
{
TRISCbits.TRISC3=1; // Set up I2C lines by setting as input
TRISCbits.TRISC4=1;
SSPCON1 = 0b00101000; 
// SSPADD=(FOSC / (4 * I2C_FREQ)) - 1; //clock 100khz
SSPADD = 0x18 ; //clock 100khz
SSPSTAT=80; // Slew rate control disabled

PIR1bits.SSPIF = 0; // Clear MSSP interrupt request flag
PIE1bits.SSPIE = 1; // Enable MSSP interrupt enable bit

}

当我将其连接到示波器时，在发送SEN = 1后，SDA和SCL端口没有任何反应。请帮我解决这个问题。很久以来我一直坚持这个。

Answer 1

PIR1不是寄存器：数据表将其显示为寄存器while(!SSPIF); // while SSPIF=0 stay here else exit the loop SSPIF = 0; // operation completed clear the flag中的第3位，而不是行

while ((PIR1 & 0x08) == 0);
PIR1 = 0;

这意味着您应该使用

进行测试和清除

BCF PIR1,SSPIF ;I2C done, clear flag

清除状态的汇编程序指令是

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代码的更多细节是in this forum，另请阅读数据表以获取更多信息。

PIC I2C与外部EEPROM通信

1 个答案: