IIC bus program (chip AT24C02 EEPROM)

 1 #include
 2 #define uint unsigned int < br /> 3 #define uchar unsigned char
 4 
 5 sbit SCL =P2^1 ;
 6 sbit SDA =P2^0;
 7 
 8 sbit K1 =P3^0; 
 9 sbit K2 =P3^1;
 10 sbit K3 =P3^0;
 11 sbit K4 =P3^1;
 12 
< span style="color: #008080"> 13 sbit LSA =P2^2;
 14 sbit LSB =P2^3;
 15 sbit LS C =P2^4;
 16 uchar num;
 17 uchar code smgduan[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f< /span>,0x6f};
 18 
 19 /********************************************** *********************************
 20 * Function name: Delay10us()
 21 * Function function: Delay Hour 10us
 22 * Input: None
< span style="color: #008080"> 23 * Output: None
 24  *********************************** ********************************************/
 25 void Delay10us()//The delay is determined by calculation to be 10uM
 26 {
 27 unsigned char a,b;
 28 for(b=1;b>0;b--)
 29 for(a=2;a>0 ;a--);
 30 
 31 }
 32 /************************** ************************************************** ***
 33 * Function name: I2cStart()
< /span> 34 * Function: Start signal: SDA signal is generated during the high level of SCL clock signal A falling edge
 35 * Input: None
 36 * Output : None
 37 * Note: SDA and SCL are both 0 after the start< br /> 38 **************** ************************************************** *************/
 39< /span> 
 40 void I2cStart()
 41 {
 42 SDA=1;
 43  Delay10us();
 44 SCL=1;
 45  Delay10us();//The setup time is the SDA hold time>4.7us< br /> 46 SDA=0;< br /> 47 Delay10us();//The hold time is >4us
 48 SCL=0; 
 49  Delay10us (); 
 50 }
 51 /********** ******************************************** *************************
 52 < span style="color: #008000">* Function name: I2cStop()
 53 * Function: Termination signal: SDA signal generates a rising edge during the high level of SCL clock signal
 54 * Input: None
 55 * Output: None
 56 * Note: Keep both SDA and SCL at 1 after the end; means Bus is idle
 57 ************* ************************************************** ****************/
 58 
 59 void I2cStop()
 60 {
 61 SDA=0;
 62  Delay10us();
 63 SCL= 1;
 64 Delay10us();//The establishment time is greater than 4.7us
 65 SDA=1;
 66  Delay10us(); 
 67 }
 68 //Write bytes for IIC< br /> 69 uchar IICsendByte(uchar dat)
 70 {
 71 uchar a=< span style="color: #800080">0,b;
 72< /span> SDA =dat;
 73 for(a=0;a<8;a++)
 74  {
  75 SDA =dat>>7; //Take out the highest bit, and then move all other bits to the right
 76 dat =dat<<1; // Because the value of dat has not changed, so, leave it to the left Shift one place, the highest shift will drop, and the second highest position will become the highest position
 77 SDA =1;
 78 delay(1);
 79 SCL=< span style="color: #800080">0;
 80 delay(1);
 81} //At this time, all 8-bit data has been transmitted, and then we will respond. span>
 82 SDA=1; //SDA and SCL are set to 1 to pave the way for the following answer
 83 delay(1);
 84 SCL=1;
 85 // delay(1);
 86 while (SDA) //When the answer is successful, SDA=0; jump out of the loop 
 87  {
 88 b++;
 89 if(b>200)
 90 SCL=< span style="color: #800080">0;
 91 dealy(1);
 92 return 0;  //Indicates that the sending (communication) failed
 93  }
 94 SCL =0;
 95 delay( 1); 
 96 return 1; //When the sending is successful, return 1
 97 }
 98 //Read bytes for IIC
  99 uchar IICReadByte()
 100 {
101 uchar a,dat =0;
102 SD1= 1; //First let it pull High, let it be idle, so as not to make the data of the following SDA low
103 delay(1);
104 for(a=0;a<8;a++)
105< /span>  {
106 SCL =1; //In order to read data, first make SCL high, just to make Read again when the data is stable
107 dealy(1);
108 dat<<=1 ; // 0 00 10 110 must be placed in front of dat|=SDA, otherwise After putting all the 8-bit data in dat, if you move it by one bit, the highest displacement will be moved. If the data is wrong, it will be shifted by one bit to the left. When the second cycle comes over, this will be saved in the dat. The data will continue to move to the left once
109 dat|=SDA; //< /span> 01 11 111 That is to say, it only needs to move 7 times, and the highest displacement is not allowed to da t Perform a "bitwise OR" with SDA to assign the value of SDA to dat 
110 delay(1);
111 SCL=0; //Let SCL low is to make Data change
112 delay(1);
113  }
114 return dat;
 115 }
116 //Chip AT24C02 communication read and write
117 void AT24C02writeByte(uchar add,uchar dat)
118 < span style="color: #000000">{
119  IICstart(); 
120 IICsendByte(0xa0);//This is the device address. The upper four digits of the 8-bit are fixed and the last digit represents 0 for writing, 1 for reading, and the remaining three digits. Bits A1, A2, A3, we got the ground
121  IICsendByte(add) ;
122 IICsendByte(dat);//We thank you in the byte function of IIC
123  IICStop();
124 }
125 uchar AT24C02rea d(uchar add)//Because it is to read the signal, it is necessary to know the address of the read< /span>
126 {
127  uchar value;
128  IICstart();
129 IICsendByte(0xa0 );//This is the device address, the upper four digits of 8 bits are the last fixed digit It means 0 for writing, 1 for reading, and the remaining three digits A1, A2, and A3, and we are connected to the ground
130  IICsendByte(add);
131 IICstart(); //Because the address must be written before and the data inside will be read later, the direction of reading and writing will change, so it must be rewritten Start signal and device address
132 IICsendByte(0 xa1);
133 value =IICReadByte();//Read the data in the address directly, and save the value read back to value< br />134  IICstop();
135 return value; 
136 }
137 //Independent key function
138< /span> void keypros()
139 {
140 if (K1==0)
141  {
142 delay(10);
143 if (K1==0)
144  {
145 AT24C02writeByte(1,num); //Key 1 realizes the value of num, Write it into the address of 1, because the AT24C02 chip has 255 memory
146  }
147 while( !K1);// Determine whether the button is released. If you forget to write this statement, the function of this function will not stop To proceed
148  }
149 if (K2==0)
150  {
 151 delay(10) ;
152 if(K2==0)
153  {
154 num =AT24C02read(1< /span>); //Read out the data stored in the memory of 1, and assign it to the value of the variable num span>
155  }
156 while(!K2);
157  }
158 
159 if (K3==0)
160  {
161 delay(10);
162 if( K3==0)
163  {
164 num++; / /Add 1 to the value of num
165 if(num>255) //Because the variable of num is uchar, it can only store 255 characters
166 num =0; 
167   }
168 while(!K3);
169  }
170 if (K4==0)
 171  {
172 span> delay(10);
173 if(K4==0)
174  {
< span style="color: #008080">175 num =0; //Meticulously clear num to zero
176  }
177 while(!K4);
178  }
< /span>179 }
 180 /****************** ************************************************** ***********
181 * Function name: DigDisplay()
182 * Function function: digital tube display function
 183 * Input: None
184 * Output: None
185 ************************************* ******************************************/
186 void DigDisplay()
187 {
188  u8 i;
189 for(i=0;i<4;i++)
190  {
191 switch (i) //bit selection, select the digital tube to light up,< br />192  {
193 case(0):
194 LSA=0;LSB=0;LSC=0; break;//Display 0th place
195 case
195 case span>(1):
196 LSA=1;LSB=0;LSC=0; break;//Display 1st place
197 case(2):
198 LSA =0;LSB=1;LSC= 0; break;//Display 2nd place
199 case(3):
200 LSA =1;LSB=1;LSC= 0; break;//Display 3rd place
201  }
202 P0=disp[3-i];//Send data
203 delay(100); //Scan at intervals
204  P0=0x00;//Blanking
205 } 
206 }
207 < span style="color: #008000">/************************ ************************************************** *****
208 * Function name: datapros()
209 * Function function: data processing function
210 * 输入: 无
211 * 输出: 无
212 ********** ************************************************** *******************/
213 void datapros()
214 {
215     disp [0]=smgduan[num/1000]; //千位
216     disp[1]=smgduan[num%1000/100];//百位
217     disp[2]=smgduan[num%1000%100/10];//个位
218     disp[3]=smgduan[num%1000%100%10];        
219 }
220 void main()
221 {    
222     while(1)
223     {
224         Keypros();     //按键处理函数
225         datapros();     //数据处理函数
226         DigDisplay();//数码管显示函数        
227     }        
228 }