jay_3189
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I am using DS1307 and 89C51 controller. here I am trying to display time in hyper terminal.
I have read datasheet of DS1307 and there I found that 100kHz is standard clock rate for using I2c and DS1307. so, its mean I have to give only specific clock with delay or I can give any delay.
please check my below I2C code. is that work better or not.
At this time I am not getting tome accurate.
I have read datasheet of DS1307 and there I found that 100kHz is standard clock rate for using I2c and DS1307. so, its mean I have to give only specific clock with delay or I can give any delay.
please check my below I2C code. is that work better or not.
Code:
/*-------------------------------------------------------------
I2C
--------------------------------------------------------------*/
/*This function is used to generate a clock pulse on SCL line.*/
void I2C_Clock(void)
{
delay_us(5);
SCL = 1; // Wait for Some time and Pull the SCL line High
delay_us(5); // Wait for Some time
SCL = 0; // Pull back the SCL line low to Generate a clock pulse
}
/*This function is used to generate I2C Start Condition.
Start Condition: SDA goes low when SCL is High.*/
void I2C_Start()
{
SCL = 0; // Pull SCL low
SDA = 1; // Pull SDA High
delay_us(1);
SCL = 1; //Pull SCL high
delay_us(1);
SDA = 0; //Now Pull SDA LOW, to generate the Start Condition
delay_us(1);
SCL = 0; //Finally Clear the SCL to complete the cycle
}
/*Stop Condition: SDA goes High when SCL is High.
SCL __-----------
SDA ______------*/
void I2C_Stop(void)
{
SCL = 0; // Pull SCL low
delay_us(1);
SDA = 0; // Pull SDA low
delay_us(1);
SCL = 1; // Pull SCL High
delay_us(1);
SDA = 1; // Now Pull SDA High, to generate the Stop Condition
}
/*This function is used to send a byte on SDA line using I2C protocol
8bit data is sent bit-by-bit on each clock cycle. MSB(bit) is sent first and LSB(bit) is sent at last.
Data is sent when SCL is low.*/
void I2C_Write(unsigned char dat)
{
unsigned char i;
for(i=0;i<8;i++) // loop 8 times to send 1-byte of data
{
SDA = dat & 0x80; // Send Bit by Bit on SDA line
I2C_Clock(); // Generate Clock at SCL
dat = dat<<1;
}
SDA = 1; // Set SDA at last
}
/*This fun is used to receive a byte on SDA line using I2C protocol.
8bit data is received bit-by-bit each clock and finally packed into Byte.
MSB(bit) is received first and LSB(bit) is received at last.*/
unsigned char I2C_Read(void)
{
unsigned char i, dat=0x00;
SDA=1; //Make SDA as I/P
for(i=0;i<8;i++) // loop 8times to read 1-byte of data
{
delay_us(1);
SCL = 1; // Pull SCL High
delay_us(1);
dat = dat<<1; //dat is Shifted each time and
dat = dat | SDA; //ORed with the received bit to pack into byte
SCL = 0; // Clear SCL to complete the Clock
}
return dat; // Finally return the received Byte*
}
/*This function is used to generate a the Positive ACK
pulse on SDA after receiving a byte.*/
void I2C_Ack()
{
SDA = 0; //Pull SDA low to indicate Positive ACK
I2C_Clock(); //Generate the Clock
SDA = 1; // Pull SDA back to High(IDLE state)
}
/*This function is used to generate a the Negative/NO ACK
pulse on SDA after receiving all bytes.*/
void I2C_NoAck()
{
SDA = 1; //Pull SDA high to indicate Negative/NO ACK
I2C_Clock(); // Generate the Clock
SCL = 1; // Set SCL
}At this time I am not getting tome accurate.
