Software simulation to implement the iic protocol (51 as an example)

94 scl=0; // Pull scl low to facilitate updating sda data in the next clock cycle

95         delay();

96     }

97 return k; // Read 1 byte of data from sda

98 }

99

100 // (6) Write a byte of data to a certain address (such as EEPROM)

101 void write_add(uchar address,uchar date)

102 {

103 start(); // The host sends a start signal

104 write_byte(0xa0); // Host writes device address

105 ack(); // Slave responds

106 write_byte(address); // The host writes the address of the data to be written

107 ack(); // Slave responds

108 write_byte(date); // Host writes data

109 ack(); // Slave responds

110     stop();

111 }

112 // (7) Read one byte of data from a certain address (such as EEPROM)

113 uchar read_add(uchar address)

114 {

115 flying dates;

116     start();

117 write_byte(0xa0); // write device address, write mode

118     ack();

119 write_byte(address); // write the address of the read data

120     ack();

121     start();

122 write_byte(0xa1); // write device address, read mode

123     ack();

124 date=read_byte(); // Data read from a specific address

125     stop();

126     return date;

127 }

6. Complete code (taking 51 as an example)

#include

#define uchar unsigned char

sbit sda=P2^0;

sbit scl=P2^1;

flying a;

void delay()

{ ;; }

void start() // start signal

{

sda=1;

delay();

scl=1;

delay();

sda=0;

delay();

}

void stop() // Stop

{

sda=0;

delay();

scl=1;

delay();

sda=1;

delay();

}

void respons() // Response

{

flying i;

scl=1;

delay();

while((sda==1)&&(i<250))i++;

scl=0;

delay();

}

void init()

{

sda=1;

delay();

scl=1;

delay();

}

void write_byte(uchar date)

{

flying i,temp;

temp=date;

for(i=0;i<8;i++)

{

temp=temp<<1;

scl=0;

delay();

sda=CY;

delay();

scl=1;

delay();

}

scl=0;

delay();

sda=1;

delay();

}

uchar read_byte()

{

flying i,k;

scl=0;

delay();

sda=1;

delay();

for(i=0;i<8;i++)

{

scl=1;

delay();

k=(k<<1)|sda;

scl=0;

delay();

}

return k;

}

void delay1(fly x)

{

fly a,b;

for(a=x;a>0;a--)

for(b=100;b>0;b--);

}

void write_add(uchar address,uchar date)

{

start();

write_byte(0xa0);

response();

write_byte(address);

response();

write_byte(date);

response();

stop();

}

uchar read_add(uchar address)

{

flying date;

start();

write_byte(0xa0);

response();

write_byte(address);

response();

start();

write_byte(0xa1);

response();

date=read_byte();

stop();

return date;

}

void main()

{

heat();

write_add(23,0xaa);

delay1(100); // Add delay to prevent timing errors

P1=read_add(23);

while(1);

}