Real time clock with two alarms using DS1307 RTCC and PIC18F4550 microcontroller
We have seen how to make a simple real time clock and calendar using PIC18F4550 microcontroller and DS1307 RTC chip at:
Real time clock with PIC18F4550 and DS1307 RTC
Now let’s see how to add 2 alarms to the previous project with some changes.
About DS1307 RTC:
The DS1307 is an 8-pin integrated circuit uses I2C communication protocol to communicate with master device which is in our case the PIC18F4550 microcontroller. This small chip can count seconds, minutes, hours, day, date, month and year with leap-year up to year 2100.
The DS1307 receives and transfers data (clock data and calendar data) as BCD format, so after receiving data we have to convert these data into decimal data, and before writing data to the DS1307 we have to convert this data from decimal to BCD format. For example we have the BCD number 33, converting this number into decimal gives 21.
The following image shows the DS1307 pin configurations:
And the following circuit is typical operating circuit for the DS1307 RTC:
A 3V battery can be connected between VBAT and GND as a backup supply input.
The DS1307 uses an external 32.768KHz crystal and there is no need to add any resistors or capacitors with it.
The time and calendar information is obtained by reading the appropriate register bytes. The time and calendar are set or initialized by writing the appropriate register bytes. The contents of the time and calendar registers are in the BCD format. The following table shows the DS1307 RTC registers:
More details in the DS1307 RTC datasheet.
Real time clock with 2 alarms using PIC18F4550 and DS1307 circuit:
Required Components:
- PIC18F4550 Microcontroller
- DS1307
- 2004 (20×4) LCD
- 3V Cell Battery
- 32.768KHz crystal oscillator
- 2 x 10K resistors
- 10K Potentiometer
- 470Ohm resistor
- 3 Buttons
- LED (For Alarm 1)
- Buzzer (For Alarm 2)
- +5V Power Supply
- Protoboard
- Jumper Wires
In this project PIC18F4550 microcontroller internal oscillator is used (8MHz) and MCLR pin function is disabled.
Real time clock with 2 alarms using PIC18F4550 and DS1307 C code:
Tested with CCS PIC C compiler version 5.051.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 | // Real time clock with 2 alarms using PIC18F4550 and DS1307 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) #use pwm (PWM1, FREQUENCY = 2400Hz, DUTY = 50, PWM_OFF) short alarm1_status, alarm2_status, button_state; char time[] = "TIME: : : "; char calendar[] = " / /20 "; char alarm1[] = "ALARM1: 00:00:00"; char alarm2[] = "ALARM2: 00:00:00"; unsigned int8 second, second10, minute, minute10, hour, hour10, date, date10, month, month10, year, year10, day, alarm1_minute=0, alarm1_hour=0, alarm2_minute=0, alarm2_hour=0, i, j; 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[15] = second + 48; time[14] = second10 + 48; time[12] = minute + 48; time[11] = minute10 + 48; time[9] = hour + 48; time[8] = 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:Su"); break; case 2: lcd_putc("DATE:Mo"); break; case 3: lcd_putc("DATE:Tu"); break; case 4: lcd_putc("DATE:We"); break; case 5: lcd_putc("DATE:Th"); break; case 6: lcd_putc("DATE:Fr"); break; case 7: lcd_putc("DATE:Sa"); break;} lcd_gotoxy(9, 2); // Go to column 9 row 2 printf(lcd_putc, calendar); // Display calendar } void alarm_display(){ // Display alarms info alarm1[12] = alarm1_minute % 10 + 48; alarm1[11] = alarm1_minute/10 + 48; alarm1[9] = alarm1_hour%10 + 48; alarm1[8] = alarm1_hour/10 + 48; lcd_gotoxy(21, 1); // Go to column 1 row 3 printf(lcd_putc, alarm1); lcd_gotoxy(38, 1); if(alarm1_status) lcd_putc("ON "); else lcd_putc("OFF"); alarm2[12] = alarm2_minute % 10 + 48; alarm2[11] = alarm2_minute/10 + 48; alarm2[9] = alarm2_hour%10 + 48; alarm2[8] = alarm2_hour/10 + 48; lcd_gotoxy(21, 2); // Go to column 1 row 4 printf(lcd_putc, alarm2); lcd_gotoxy(38, 2); if(alarm2_status) lcd_putc("ON "); else lcd_putc("OFF"); } 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 } void alarm_check(){ if((alarm1_minute == ((minute & 0x0F) + (minute >> 4) * 10)) && (alarm1_hour == ((hour & 0x0F) + (hour >> 4) * 10)) && (second == 0) && alarm1_status) output_high(PIN_B5); // Alarm1 ON if((alarm2_minute == ((minute & 0x0F) + (minute >> 4) * 10)) && (alarm2_hour == ((hour & 0x0F) + (hour >> 4) * 10)) && (second == 0) && alarm2_status) pwm_on(); // Alarm2 ON } int8 edit(int8 parameter, int8 xx, int8 yy){ while(TRUE){ if(input(PIN_B2) && input(PIN_B4)) button_state = 0; while(!input(PIN_B3)){ parameter++; if(((i == 1) || (i == 6)) && parameter > 23) parameter = 0; if(((i == 2) || (i == 7)) && 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); if((i == 6) || (i == 7)){ ds1307_read(); ds1307_display();} delay_ms(200);} lcd_gotoxy(xx, yy); lcd_putc(" "); j = 0; while((input(PIN_B2) || button_state || (i==6) || (i==7)) && (input(PIN_B4) || button_state || ((i != 6) && (i != 7))) && 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||(i == 6) || (i == 7)) && (input(PIN_B4) || button_state || ((i != 6) && (i != 7))) && input(PIN_B3) && j < 5){ j++; delay_ms(50);} if((i != 6) && (i != 7) && !input(PIN_B2) && !button_state){ button_state = 1; return parameter;} if((i == 6) || (i == 7)){ if(!input(PIN_B4) && (!button_state)){ button_state = 1; return parameter;} ds1307_read(); ds1307_display(); } } } short alarm_on_off(short number){ short alarm; while(TRUE){ if(input(PIN_B4)) button_state = 0; ds1307_read(); ds1307_display(); while(!input(PIN_B3)){ alarm++; lcd_gotoxy(38, number+1); if(alarm) lcd_putc("ON "); else lcd_putc("OFF"); delay_ms(200); } lcd_gotoxy(38, number+1); lcd_putc(" "); j=0; while(input(PIN_B3) && (input(PIN_B4) || button_state) && j < 5){ j++; delay_ms(50);} lcd_gotoxy(38, number+1); if(alarm) lcd_putc("ON "); else lcd_putc("OFF"); if(!input(PIN_B4) && !button_state){ button_state = 1; return alarm;} j=0; while(input(PIN_B3) && (input(PIN_B4) || button_state) && j < 5){ j++; delay_ms(50);} } } void main(){ setup_oscillator(OSC_8MHZ); // Set internal oscillator to 8MHz setup_adc_ports(NO_ANALOGS); port_b_pullups(TRUE); // Enable PORTB pull-ups output_b(0); set_tris_b(0x1F); // Configure RB0 & RB1 as inputs lcd_init(); // Initialize LCD module lcd_putc('\f'); // LCD clear while(TRUE){ if(input(PIN_B2) && input(PIN_B4)) 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, 9, 1); i=2; minute = edit(minute, 12, 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("Su"); break; case 2: lcd_putc("Mo"); break; case 3: lcd_putc("Tu"); break; case 4: lcd_putc("We"); break; case 5: lcd_putc("Th"); break; case 6: lcd_putc("Fr"); break; case 7: lcd_putc("Sa"); 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("Su"); break; case 2: lcd_putc("Mo"); break; case 3: lcd_putc("Tu"); break; case 4: lcd_putc("We"); break; case 5: lcd_putc("Th"); break; case 6: lcd_putc("Fr"); break; case 7: lcd_putc("Sa"); 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, 9, 2); i=4; month = edit(month, 12, 2); i=5; year = edit(year, 17, 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); } if(!input(PIN_B4) && (!button_state)){ button_state = 1; i=6; alarm1_hour = edit(alarm1_hour, 29, 1); i=7; alarm1_minute = edit(alarm1_minute, 32, 1); alarm1_status = alarm_on_off(0); i=6; alarm2_hour = edit(alarm2_hour, 29, 2); i=7; alarm2_minute = edit(alarm2_minute, 32, 2); alarm2_status = alarm_on_off(1); delay_ms(200); } if(input(PIN_B3) == 0){ output_low(PIN_B5); pwm_off(); } ds1307_read(); // Read data from DS1307 RTCC alarm_check(); // Check if there is an alarm ds1307_display(); // Diaplay time and calendar alarm_display(); // Display alarms delay_ms(50); } } |
Project video:
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