Ales Povalac / DS1307

Dallas DS1307 real-time clock minimalistic driver

Dependents:   testing_RTC_OneWire EMIRv2

DS1307.cpp@1:60383faa35a9, 2014-04-27 (annotated)

Committer:
alpov
Date:
Sun Apr 27 19:07:57 2014 +0000
Revision:
1:60383faa35a9
Parent:
0:f29e45a25cba
Child:
2:6d8d35a5b3f2
added docu, even more simplification, constants

Who changed what in which revision?

UserRevisionLine numberNew contents of line
alpov 0:f29e45a25cba 1 #include "mbed.h"
alpov 0:f29e45a25cba 2 #include "DS1307.h"
alpov 0:f29e45a25cba 3
alpov 1:60383faa35a9 4 DS1307::DS1307(PinName sda, PinName scl) : ds1307_i2c(sda, scl)
alpov 0:f29e45a25cba 5 {
alpov 1:60383faa35a9 6 ds1307_i2c.frequency(DS1307_FREQ);
alpov 0:f29e45a25cba 7 }
alpov 0:f29e45a25cba 8
alpov 1:60383faa35a9 9 time_t DS1307::now()
alpov 0:f29e45a25cba 10 {
alpov 0:f29e45a25cba 11 struct tm now;
alpov 1:60383faa35a9 12 char addr = 0x00; // memory address
alpov 0:f29e45a25cba 13 char buffer[7];
alpov 1:60383faa35a9 14
alpov 1:60383faa35a9 15 if (ds1307_i2c.write(DS1307_ADDR, &addr, 1) != 0) return 0;
alpov 1:60383faa35a9 16 if (ds1307_i2c.read(DS1307_ADDR, buffer, 7) != 0) return 0;
alpov 0:f29e45a25cba 17
alpov 1:60383faa35a9 18 if (buffer[0] & 0x80) return 0; // clock stopped
alpov 0:f29e45a25cba 19 if (!(buffer[2] & 0x40)) return 0; // 12-hour format not supported
alpov 0:f29e45a25cba 20 now.tm_sec = bcdToDecimal(buffer[0] & 0x7F);
alpov 0:f29e45a25cba 21 now.tm_min = bcdToDecimal(buffer[1]);
alpov 0:f29e45a25cba 22 now.tm_hour = bcdToDecimal(buffer[2] & 0x3F);
alpov 0:f29e45a25cba 23 now.tm_wday = buffer[3];
alpov 0:f29e45a25cba 24 now.tm_mday = bcdToDecimal(buffer[4]);
alpov 0:f29e45a25cba 25 now.tm_mon = bcdToDecimal(buffer[5]) - 1;
alpov 0:f29e45a25cba 26 now.tm_year = bcdToDecimal(buffer[6]) + 2000 - 1900;
alpov 0:f29e45a25cba 27
alpov 0:f29e45a25cba 28 return mktime(&now);
alpov 0:f29e45a25cba 29 }
alpov 0:f29e45a25cba 30
alpov 1:60383faa35a9 31 bool DS1307::set_time(time_t t)
alpov 0:f29e45a25cba 32 {
alpov 0:f29e45a25cba 33 struct tm *now;
alpov 1:60383faa35a9 34 char buffer[9];
alpov 0:f29e45a25cba 35
alpov 0:f29e45a25cba 36 now = localtime(&t);
alpov 0:f29e45a25cba 37
alpov 1:60383faa35a9 38 buffer[0] = 0x00; // memory address
alpov 1:60383faa35a9 39 buffer[1] = decimalToBcd(now->tm_sec) & 0x7f; // CH = 0
alpov 1:60383faa35a9 40 buffer[2] = decimalToBcd(now->tm_min);
alpov 1:60383faa35a9 41 buffer[3] = 0x40 | (decimalToBcd(now->tm_hour) & 0x3F); // 24-hour format
alpov 1:60383faa35a9 42 buffer[4] = now->tm_wday + 1;
alpov 1:60383faa35a9 43 buffer[5] = decimalToBcd(now->tm_mday);
alpov 1:60383faa35a9 44 buffer[6] = decimalToBcd(now->tm_mon+1);
alpov 1:60383faa35a9 45 buffer[7] = decimalToBcd(now->tm_year + 1900 - 2000);
alpov 1:60383faa35a9 46 buffer[8] = 0x00; // OUT = 0
alpov 1:60383faa35a9 47 if (ds1307_i2c.write(DS1307_ADDR, buffer, 9) != 0) return false;
alpov 0:f29e45a25cba 48
alpov 0:f29e45a25cba 49 return true;
alpov 0:f29e45a25cba 50 }