Chuẩn bị linh kiện:
- PIC18F4550
- DS1307 RTC
- DHT22 (AM2302 – RHT03)
- Màn hình 20×4 LCD
- Pin 3V
- Thạch anh 32.768KHz
- Điện trở 2 x 10K
- Điện trở 4.7K
- Chiết áp/ biến trở 10K
- 2 nút nhấn
- Nguồn +5V
- Board cắm
- Dây cắm board
Code trên CCS
// PIC18F4550 with DS1307 and DHT22 (AM2302-RHT03) CCS C code
//LCD module connections
#define LCD_RS_PIN PIN_D0
#define LCD_RW_PIN PIN_D1
#define LCD_ENABLE_PIN PIN_D2
#define LCD_DATA4 PIN_D3
#define LCD_DATA5 PIN_D4
#define LCD_DATA6 PIN_D5
#define LCD_DATA7 PIN_D6
//End LCD module connections
#include <18F4550.h>
#fuses NOMCLR INTRC_IO
#use delay(clock = 8000000)
#include <lcd.c>
#use fast_io(B)
#use I2C(master, I2C1, FAST=100000)
#define DHT22_PIN PIN_B4 // Connection pin between DHT22 and mcu
short button_state, Time_out;
char time[] = "TIME: : : ";
char calendar[] = " / /20 ";
unsigned int8 second, second10, minute, minute10,
hour, hour10, date, date10, month, month10,
year, year10, day, i, j ;
char message1[] = "Temperature: 00.0 C ";
char message2[] = "Humidity : 00.0 % ";
unsigned int8 T_byte1, T_byte2, RH_byte1, RH_byte2, CheckSum, time_read ;
unsigned int16 Temp, RH;
void ds1307_display(){
second10 = (second & 0x70) >> 4;
second = second & 0x0F;
minute10 = (minute & 0x70) >> 4;
minute = minute & 0x0F;
hour10 = (hour & 0x30) >> 4;
hour = hour & 0x0F;
date10 = (date & 0x30) >> 4;
date = date & 0x0F;
month10 = (month & 0x10) >> 4;
month = month & 0x0F;
year10 = (year & 0xF0) >> 4;
year = year & 0x0F;
time[16] = second + 48;
time[15] = second10 + 48;
time[13] = minute + 48;
time[12] = minute10 + 48;
time[10] = hour + 48;
time[9] = hour10 + 48;
calendar[9] = year + 48;
calendar[8] = year10 + 48;
calendar[4] = month + 48;
calendar[3] = month10 + 48;
calendar[1] = date + 48;
calendar[0] = date10 + 48;
lcd_gotoxy(1, 1); // Go to column 1 row 1
printf(lcd_putc, time); // Display time
lcd_gotoxy(1, 2); // Go to column 1 row 2
switch(day){
case 1: lcd_putc("DATE:Sun"); break;
case 2: lcd_putc("DATE:Mon"); break;
case 3: lcd_putc("DATE:Tue"); break;
case 4: lcd_putc("DATE:Wed"); break;
case 5: lcd_putc("DATE:Thu"); break;
case 6: lcd_putc("DATE:Fri"); break;
case 7: lcd_putc("DATE:Sat"); break;}
lcd_gotoxy(10, 2); // Go to column 10 row 2
printf(lcd_putc, calendar); // Display calendar
}
void ds1307_write(unsigned int8 address, data_){
i2c_start(); // Start I2C
i2c_write(0xD0); // DS1307 address
i2c_write(address); // Send register address
i2c_write(data_); // Write data to the selected register
i2c_stop(); // Stop I2C
}
void ds1307_read(){
i2c_start(); // Start I2C
i2c_write(0xD0); // DS1307 address
i2c_write(0); // Send register address
i2c_start(); // Restart I2C
i2c_write(0xD1); // Initialize data read
second =i2c_read(1); // Read seconds from register 0
minute =i2c_read(1); // Read minuts from register 1
hour = i2c_read(1); // Read hour from register 2
day = i2c_read(1); // Read day from register 3
date = i2c_read(1); // Read date from register 4
month = i2c_read(1); // Read month from register 5
year = i2c_read(0); // Read year from register 6
i2c_stop(); // Stop I2C
}
int8 edit(int8 parameter, int8 xx, int8 yy){
while(TRUE){
if(input(PIN_B2)) button_state = 0;
while(!input(PIN_B3)){
parameter++;
if(i == 1 && parameter > 23)
parameter = 0;
if(i == 2 && parameter > 59)
parameter = 0;
if(i == 3 && parameter > 31)
parameter = 1;
if(i == 4 && parameter > 12)
parameter = 1;
if(i == 5 && parameter > 99)
parameter = 0;
lcd_gotoxy(xx, yy);
printf(lcd_putc,"%02u", parameter);
delay_ms(200);}
lcd_gotoxy(xx, yy);
lcd_putc(" ");
j = 0;
while((input(PIN_B2) || button_state) && input(PIN_B3) && j < 5){
j++;
delay_ms(50);}
lcd_gotoxy(xx, yy);
printf(lcd_putc,"%02u", parameter);
j = 0;
while((input(PIN_B2) || button_state) && input(PIN_B3) && j < 5){
j++;
delay_ms(50);}
if(!input(PIN_B2) && !button_state){
button_state = 1; return parameter;}
}
}
void start_signal(){
output_drive(DHT22_PIN); // Configure connection pin as output
output_low(DHT22_PIN); // Connection pin output low
delay_ms(25);
output_high(DHT22_PIN); // Connection pin output high
delay_us(30);
output_float(DHT22_PIN); // Configure connection pin as input
}
short check_response(){
delay_us(40);
if(!input(DHT22_PIN)){ // Read and test if connection pin is low
delay_us(80);
if(input(DHT22_PIN)){ // Read and test if connection pin is high
delay_us(50);
return 1;
}
}
}
unsigned int8 Read_Data(){
unsigned int8 i, k, _data = 0; // k is used to count 1 bit reading duration
if(Time_out)
break;
for(i = 0; i < 8; i++){
k = 0;
while(!input(DHT22_PIN)){ // Wait until pin goes high
k++;
if (k > 100) {Time_out = 1; break;}
delay_us(1);}
delay_us(30);
if(!input(DHT22_PIN))
bit_clear(_data, (7 - i)); // Clear bit (7 - i)
else{
bit_set(_data, (7 - i)); // Set bit (7 - i)
while(input(DHT22_PIN)){ // Wait until pin goes low
k++;
if (k > 100) {Time_out = 1; break;}
delay_us(1);}
}
}
return _data;
}
void main(){
setup_oscillator(OSC_8MHZ); // Set internal oscillator to 8MHz
setup_adc_ports(NO_ANALOGS); // Configure all AN pins as digital
port_b_pullups(TRUE); // Enable PORTB pull-ups
output_b(0);
set_tris_b(0x0F); // Configure RB0,RB1,RB2 & RB3 as inputs
lcd_init(); // Initialize LCD module
lcd_putc('\f'); // LCD clear
while(TRUE){
Time_out = 0;
if(input(PIN_B2)) button_state = 0;
if(!input(PIN_B2) && (!button_state)){
button_state = 1;
// Convert BCD to decimal
minute = minute + minute10 * 10;
hour = hour + hour10 * 10;
date = date + date10 * 10;
month = month + month10 * 10;
year = year + year10 * 10;
// End conversion
i=1;
hour = edit(hour, 10, 1);
i=2;
minute = edit(minute, 13, 1);
while(TRUE){
if(input(PIN_B2))
button_state = 0;
while(!input(PIN_B3)){
day++;
if(day > 7)
day = 1;
lcd_gotoxy(6, 2); // Go to column 6 row 2
switch(day){
case 1: lcd_putc("Sun"); break;
case 2: lcd_putc("Mon"); break;
case 3: lcd_putc("Tue"); break;
case 4: lcd_putc("Wed"); break;
case 5: lcd_putc("Thu"); break;
case 6: lcd_putc("Fri"); break;
case 7: lcd_putc("Sat"); break;}
delay_ms(200);
}
lcd_gotoxy(6, 2);
lcd_putc(" ");
j = 0;
while((input(PIN_B2)||button_state) && input(PIN_B3) && j < 5){
j++;
delay_ms(50);}
lcd_gotoxy(6, 2);
switch(day){
case 1: lcd_putc("Sun"); break;
case 2: lcd_putc("Mon"); break;
case 3: lcd_putc("Tue"); break;
case 4: lcd_putc("Wed"); break;
case 5: lcd_putc("Thu"); break;
case 6: lcd_putc("Fri"); break;
case 7: lcd_putc("Sat"); break;}
if(!input(PIN_B2) && (!button_state)){
button_state = 1;
break;}
j = 0;
while((input(PIN_B2)||button_state) && input(PIN_B3) && j < 5){
j++;
delay_ms(50);}
}
i=3;
date = edit(date, 10, 2);
i=4;
month = edit(month, 13, 2);
i=5;
year = edit(year, 18, 2);
// Convert decimal to BCD
minute = ((minute/10) << 4) + (minute % 10);
hour = ((hour/10) << 4) + (hour % 10);
date = ((date/10) << 4) + (date % 10);
month = ((month/10) << 4) + (month % 10);
year = ((year/10) << 4) + (year % 10);
// End conversion
ds1307_write(1, minute);
ds1307_write(2, hour);
ds1307_write(3, day);
ds1307_write(4, date);
ds1307_write(5, month);
ds1307_write(6, year);
ds1307_write(0, 0);
}
ds1307_read(); // Read data from DS1307 RTCC
ds1307_display(); // Diaplay time and calendar
if(((second10 * 10+second)>time_read)||((second10 * 10+second)==0 && time_read)){
time_read = second10 * 10 + second;
Start_signal();
if(check_response()){ // If there is response from sensor
RH_byte1 = Read_Data(); // read RH byte1
RH_byte2 = Read_Data(); // read RH byte2
T_byte1 = Read_Data(); // read T byte1
T_byte2 = Read_Data(); // read T byte2
Checksum = Read_Data(); // read checksum
if(Time_out){ // If reading takes long time
lcd_gotoxy(21, 1); // Go to column 1 row 3
lcd_putc(" Time Out! ");
lcd_gotoxy(21, 2); // Go to column 1 row 4
lcd_putc(" "); // Clear 4th row
}
else{
if(CheckSum == ((RH_Byte1 + RH_Byte2 + T_Byte1 + T_Byte2) & 0xFF)){
RH = RH_byte1;
RH = (RH << 8) | RH_byte2;
Temp = T_byte1;
Temp = (Temp << 8) | T_byte2;
if(Temp > 0X8000){
message1[12] = '-';
Temp = Temp & 0X7FFF; }
else
message1[12] = ' ';
message1[13] = (Temp / 100) % 10 + 48;
message1[14] = (Temp / 10) % 10 + 48;
message1[16] = Temp % 10 + 48;
message2[13] = (RH / 100) % 10 + 48;
message2[14] = (RH / 10) % 10 + 48;
message2[16] = RH % 10 + 48;
message1[17] = 223; // Degree symbol
lcd_gotoxy(21, 1); // Go to column 1 row 1
printf(lcd_putc, message1); // Display message1
lcd_gotoxy(21, 2); // Go to column 1 row 2
printf(lcd_putc, message2); // Display message2
}
else{
lcd_gotoxy(21, 1); // Go to column 1 row 3
lcd_putc(" Checksum Error! ");
lcd_gotoxy(21, 1); // Go to column 1 row 4
lcd_putc(" "); // Clear 4th row
}
}
}
else {
lcd_gotoxy(21, 1); // Go to column 3 row 3
lcd_putc(" No response ");
lcd_gotoxy(21, 2); // Go to column 1 row 4
lcd_putc(" from the sensor ");
}
}
delay_ms(50);
}
}Theo: https://simple-circuit.com/
 DS1307 có thể đếm giờ, phút, giây, thứ, ngày tháng, năm. Giao tiếp với vi điều khiển thông qua chuẩn I2C, và đóng vai trò là slave khi kết nối đến Bus I2C này.){kind=link}