{"id":288,"date":"2016-02-28T14:06:39","date_gmt":"2016-02-28T14:06:39","guid":{"rendered":"https:\/\/www.kolkataonweb.com\/code-bank\/?p=288"},"modified":"2016-07-27T20:04:55","modified_gmt":"2016-07-27T19:04:55","slug":"ds-1302-rtc-clock-module-for-arduino","status":"publish","type":"post","link":"https:\/\/www.kolkataonweb.com\/code-bank\/arduino\/ds-1302-rtc-clock-module-for-arduino\/","title":{"rendered":"DS-1302 RTC Clock Module for Arduino"},"content":{"rendered":"

DS-1302 from Maxim (data sheet download<\/a>) is a cheap RTC chip. Below are some of the salient features.<\/p>\n

    \n
  1. Real-Time Clock Counts Seconds,Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100<\/li>\n
  2. Simple 3-Wire Interface<\/li>\n
  3. 2.0V to 5.5V Full Operation<\/li>\n
  4. TTL-Compatible (VCC = 5V)<\/li>\n
  5. 31 x 8 Battery-Backed General-Purpose RAM<\/li>\n<\/ol>\n
    There are breakout boards available on ebay, which will be handy to build RTC based projects with Arduino. Look for China based sellers for a cheap price.<\/div>\n
    <\/div>\n
    \"DS-1302<\/a> \"DS-1302<\/a>\"DS-1302<\/a>\"DS-1302<\/a><\/div>\n
    Though there are various modules available but the above two types I found to be working properly.<\/div>\n
    The below board didn't work at all. Notice the PCB trace which indicates the poor quality.Unfortunately there was no way to know this before delivery.\r\n\r\n\"DS-1302<\/a>  \"DS-1302<\/a><\/pre>\n
    For those modules which has two power pins (VCC1 and VCC2), power to be connected to VCC2, VCC1 is connected to battery<\/div>\n
    <\/div>\n
    The below code can be used to used to write and read time from the chip. Credit for the DS1302 library used here goes to Matt Sparks<\/em>.\u00a0 The library can be downloaded from Github<\/a> and also from here<\/a> (in case it goes off from Github).<\/div>\n
    <\/div>\n
    Below is a code snippet (based on Matt Spark’s work) for setting time and reading it back easily. Please note for writing to the chip VCC2 needs to be given power (I used 5v).<\/em><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0 \/\/http:\/\/datasheets.maximintegrated.com\/en\/ds\/DS1302.pdf\r\n\r\n\u00a0\u00a0\u00a0 #include <DS1302.h>\r\n\u00a0\u00a0\u00a0 \/\/#include <SoftwareSerial.h>\r\n\r\n\u00a0\u00a0\u00a0 \/\/SoftwareSerial mySerial(2, 3); \/\/ RX, TX\r\n\r\n\u00a0\u00a0\u00a0 namespace {\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Set the appropriate digital I\/O pin connections.\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 const int kCePin\u00a0\u00a0 = 8;\u00a0 \/\/ Chip Enable (Some calls it Reset)\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 const int kIoPin\u00a0\u00a0 = 7;\u00a0 \/\/ Input\/Output\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 const int kSclkPin = 6;\u00a0 \/\/ Serial Clock\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Create a DS1302 object.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 DS1302 rtc(kCePin, kIoPin, kSclkPin);\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 String dayAsString(const Time::Day day) {\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 switch (day) {\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kSunday: return \"Sunday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kMonday: return \"Monday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kTuesday: return \"Tuesday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kWednesday: return \"Wednesday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kThursday: return \"Thursday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kFriday: return \"Friday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 case Time::kSaturday: return \"Saturday\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 }\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 return \"(unknown day)\";\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 }\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 void printTime() {\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Get the current time and date from the chip.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Time t = rtc.time();\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Name the day of the week.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 const String day = dayAsString(t.day);\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Format the time and date and insert into the temporary buffer.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 char buf[50];\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 snprintf(buf, sizeof(buf), \"%s %04d-%02d-%02d %02d:%02d:%02d\",\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 day.c_str(),\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 t.yr, t.mon, t.date,\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 t.hr, t.min, t.sec);\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Print the formatted string to serial so we can see the time.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Serial.println(buf);\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/mySerial.println(buf);\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 }\r\n\r\n\u00a0\u00a0\u00a0 }\u00a0 \/\/ end of namespace\r\n\r\n\u00a0\u00a0\u00a0 void setup() {\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 Serial.begin(9600);\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/mySerial.begin(38400);\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Initialize a new chip by turning off write protection and clearing the clock halt flag.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 rtc.writeProtect(false); \/\/should be set to true after writing to prevent accidental writes\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 rtc.halt(false);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Year month day hour min sec. DOW\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 Time t(2016, 2, 28, 19, 9, 30, Time::kSunday);\r\n\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ Set the time and date on the chip.\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 rtc.time(t);\u00a0 \/\/after writing once, comment\/remove this code to prevent unnecessary\/wrong re-writing of the time\r\n\u00a0\u00a0\u00a0 }\r\n\r\n\u00a0\u00a0\u00a0 \/\/ Loop and print the time every 5 seconds.\r\n\u00a0\u00a0\u00a0 void loop() {\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 printTime(); \/\/prints the date and time\r\n\u00a0\u00a0\u00a0\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0\u00a0\u00a0 delay(5000);\r\n\u00a0\u00a0\u00a0 }<\/pre>\n","protected":false},"excerpt":{"rendered":"
    DS-1302 from Maxim (data sheet download) is a cheap RTC chip. Below are some of the salient features. Real-Time Clock Counts Seconds,Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100 Simple 3-Wire Interface 2.0V to 5.5V Full Operation TTL-Compatible (VCC = 5V) 31 x… Continue reading DS-1302 RTC Clock Module for Arduino<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[36,34,35],"class_list":["post-288","post","type-post","status-publish","format-standard","hentry","category-arduino","tag-arduino-clock","tag-arduino-rtc","tag-ds-1302","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/posts\/288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/comments?post=288"}],"version-history":[{"count":7,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/posts\/288\/revisions"}],"predecessor-version":[{"id":467,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/posts\/288\/revisions\/467"}],"wp:attachment":[{"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/media?parent=288"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/categories?post=288"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kolkataonweb.com\/code-bank\/wp-json\/wp\/v2\/tags?post=288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}