I wasn't happy with the libraries floating around for the DS1337 Real Time Clock, so I modified the example one for the DS1307 included with Time.h to add support for the alarms and square wave output. Is there a repository to upload it to share? Also anyone that wants to critique my code feel free, I'm very new to arduino.
DS1337.h:
/*
* DS1337RTC.h - library for DS1337 RTC
* This library is intended to be uses with Arduino Time.h library functions
*/
#ifndef DS1337RTC_h
#define DS1337RTC_h
#include <Time.h>
#define DS1337_CTRL_ID 0x68
#define CLOCK_ADDRESS 0x00
#define ALARM1_ADDRESS 0x07
#define ALARM2_ADDRESS 0x0B
#define STATUS_ADDRESS 0x0F
#define CONTROL_ADDRESS 0x0E
#define INTB 0
#define SQW 1
// library interface description
class DS1337RTC
{
// user-accessible "public" interface
public:
DS1337RTC();
static time_t get(int address);
static void set(time_t t, int address);
static time_t sync();
static void read(tmElements_t &tm, int address);
static void write(tmElements_t &tm, int address);
static void enableAlarm(int address);
static void disableAlarm(int address);
static void resetAlarms();
static void interruptSelect(int mode);
static void freqSelect(int freq);
private:
static uint8_t dec2bcd(uint8_t num);
static uint8_t bcd2dec(uint8_t num);
static void startClock();
static void stopClock();
};
extern DS1337RTC RTC;
#endif
DS1337.cpp:
/*
* DS1337RTC.h - library for DS1337 RTC
By Eric Trombly
modified from DS1307RTC.h (c) Michael Margolis 2009
This library is intended to be uses with Arduino Time.h library functions
The library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
7 Jul 2011 - Initial release
*/
#include <Wire.h>
#include <WProgram.h>
#include "DS1337RTC.h"
byte controlRegister = 0x18; // default settings on start
DS1337RTC::DS1337RTC()
{
Wire.begin();
}
// PUBLIC FUNCTIONS
time_t DS1337RTC::get(int address) // Aquire data from buffer and convert to time_t
{
tmElements_t tm;
read(tm, address);
return(makeTime(tm));
}
void DS1337RTC::set(time_t t, int address) // Convert from time_t and save to rtc
{
tmElements_t tm;
breakTime(t, tm);
stopClock();
write(tm, address);
startClock();
}
time_t DS1337RTC::sync() // Function to use for Time.h setSyncProvider
{
return(get(CLOCK_ADDRESS));
}
void DS1337RTC::read( tmElements_t &tm, int address) // Aquire data from the RTC chip in BCD format
{
int numberBytes;
switch(address){
case CLOCK_ADDRESS: numberBytes = tmNbrFields; break;
case ALARM1_ADDRESS: numberBytes = 4; break;
case ALARM2_ADDRESS: numberBytes = 3; break;
}
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(address);
Wire.endTransmission();
Wire.requestFrom(DS1337_CTRL_ID, numberBytes);
if(address != ALARM2_ADDRESS){ // alarm 2 doesn't have a seconds field
tm.Second = bcd2dec(Wire.receive() );
}
tm.Minute = bcd2dec(Wire.receive() );
tm.Hour = bcd2dec(Wire.receive() );
if(address == ALARM1_ADDRESS || address == ALARM2_ADDRESS){ // the alarms don't have a wday,day,month,or year field
tm.Day = bcd2dec(Wire.receive() );
tm.Month = 0;
tm.Year = 0;
}else{
tm.Wday = bcd2dec(Wire.receive() );
tm.Day = bcd2dec(Wire.receive() );
tm.Month = bcd2dec(Wire.receive() );
tm.Year = y2kYearToTm((bcd2dec(Wire.receive())));
}
}
void DS1337RTC::write(tmElements_t &tm, int address)
{
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(address);
if(address != ALARM2_ADDRESS){ // alarm 2 doesn't have a seconds field
Wire.send(dec2bcd(tm.Second));
}
Wire.send(dec2bcd(tm.Minute));
Wire.send(dec2bcd(tm.Hour));
if(address == ALARM1_ADDRESS || address == ALARM2_ADDRESS){ // the alarms don't have a wday,day,month,or year field
Wire.send(dec2bcd(tm.Day));
}else{
Wire.send(dec2bcd(tm.Wday));
Wire.send(dec2bcd(tm.Day));
Wire.send(dec2bcd(tm.Month));
Wire.send(dec2bcd(tmYearToY2k(tm.Year)));
}
Wire.endTransmission();
}
void DS1337RTC::enableAlarm(int address){ //turn on the A1IE or A2IE bit
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(CONTROL_ADDRESS);
if(address == ALARM1_ADDRESS){
controlRegister |= 0x01;
}else{
controlRegister |= 0x03;
}
Wire.send(controlRegister);
Wire.endTransmission();
}
void DS1337RTC::disableAlarm(int address){ // turn off the A1IE or A2IE bit
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(CONTROL_ADDRESS);
if(address == ALARM1_ADDRESS){
controlRegister &= 0xFE;
}else{
controlRegister &= 0xFD;
}
Wire.send(controlRegister);
Wire.endTransmission();
}
void DS1337RTC::resetAlarms(){ // reset the A1F and A2F bits
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(STATUS_ADDRESS);
Wire.send(0x00);
Wire.endTransmission();
}
void DS1337RTC::interruptSelect(int mode){ // set the INTCN bit, valid modes are INTB and SQW
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(CONTROL_ADDRESS);
if(mode == INTB){
controlRegister |= 0x04;
}else{
controlRegister &= 0xFB;
}
Wire.send(controlRegister);
Wire.endTransmission();
}
void DS1337RTC::freqSelect(int freq){ // set RS1 and RS2 bits, freq 0=1Hz, 1=4.096kHz, 2=8.192kHz, 3=32.768kHz
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(CONTROL_ADDRESS);
switch(freq){
case 0: controlRegister &= 0xE7; break;
case 1: controlRegister |= 0x08; break;
case 2: controlRegister |= 0x10; break;
case 3: controlRegister |= 0x18; break;
}
Wire.send(controlRegister);
Wire.endTransmission();
}
// PRIVATE FUNCTIONS
// Convert Decimal to Binary Coded Decimal (BCD)
uint8_t DS1337RTC::dec2bcd(uint8_t num)
{
return ((num/10 * 16) + (num % 10));
}
// Convert Binary Coded Decimal (BCD) to Decimal
uint8_t DS1337RTC::bcd2dec(uint8_t num)
{
return ((num/16 * 10) + (num % 16));
}
void DS1337RTC::stopClock(){
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(STATUS_ADDRESS);
Wire.send(0x80);
Wire.endTransmission();
}
void DS1337RTC::startClock(){
Wire.beginTransmission(DS1337_CTRL_ID);
Wire.send(STATUS_ADDRESS);
Wire.send(0x00);
Wire.endTransmission();
}
DS1337RTC RTC = DS1337RTC(); // create an instance for the user
example usage:
#include <DS1337RTC.h>
#include <Time.h>
#include <Wire.h>
#define alarmPin 12
char *monthName[12] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
void setup(){
pinMode(alarmPin, INPUT);
digitalWrite(alarmPin,HIGH);
Serial.begin(9600);
tmElements_t tmSet;
tmSet.Year = 2011 - 1970;
tmSet.Month = 7;
tmSet.Day = 3;
tmSet.Hour = 20;
tmSet.Minute = 13;
tmSet.Second = 0;
RTC.set(makeTime(tmSet), CLOCK_ADDRESS); // set the clock
tmSet.Second = 4;
RTC.set(makeTime(tmSet), ALARM1_ADDRESS); // set the alarm for 4 seconds later
RTC.enableAlarm(ALARM1_ADDRESS);
RTC.freqSelect(1); // set the squarewave freq on alarm pin b to 4.096kHz
}
void loop(){
time_t alarm = RTC.get(ALARM1_ADDRESS); // get the time the alarm is set for
tmElements_t alarmSet;
breakTime(alarm, alarmSet);
//print the time using Time.h
Serial.print(day());
Serial.print(" ");
Serial.print(monthName[month() - 1]);
Serial.print(" ");
Serial.print(year());
Serial.print(" ");
Serial.print(hour());
printDigits(minute());
printDigits(second());
Serial.print("\t");
// print the alarm time
Serial.print("ALARM1: ");
Serial.print((int)alarmSet.Day);
Serial.print(" ");
Serial.print((int)alarmSet.Hour);
printDigits(alarmSet.Minute);
printDigits(alarmSet.Second);
Serial.print("\t");
if(digitalRead(alarmPin) == HIGH){ //pin is set low when alarm is triggered
Serial.println("ALARM off");
}else{
Serial.println("ALARM on");
RTC.resetAlarms();
}
delay(1000);
}
void printDigits(int digits){
// utility function for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if(digits < 10)
Serial.print('0');
Serial.print(digits);
}