Hi... Very quick question..
How do I change the setting to be 12 hour am/pm in the following code snippet?
*hour = bcdToDec(Wire.receive() & 0x7f); //Change this if 12 hour am/pm
*hour = bcdToDec(Wire.receive() & 0x1f);
See getClock and setClock functions:
//clock SDA to analog pin 4 SCL to analog pin 5
#define DEBUG //compile serial monitor clock display
#define SETCLOCK //compile clock setup code
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68 //seven bit address
#define MAXLINE 10
#define Mode12 1
#define Mode24 0
#define AM 0
#define PM 1
static char *dayname[] =
{ "Sun",
"Mon",
"Tue",
"Wed",
"Thu",
"Fri",
"Sat"
};
void setup()
{
Wire.begin();
Serial.begin(9600);
#ifdef SETCLOCK
char ans[1];
int serbytes=0;
Serial.println("Enter 'y' to set clock");
serbytes = getSerStrWait(ans, 1, 10);
if (strcmp(ans, "y") == 0) {
setClock();
}
#endif
}
void loop()
{
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year, ampm;
getClock(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year, &m);
#ifdef DEBUG
leadzero(hour);
Serial.print(hour, DEC);
Serial.print(":");
leadzero(minute);
Serial.print(minute, DEC);
Serial.print(":");
leadzero(second);
Serial.print(second, DEC);
if (ampm != ' ') { //not space
Serial.print(" ");
Serial.print(ampm);
Serial.print("M");
}
Serial.print(" ");
leadzero(month);
Serial.print(month, DEC);
Serial.print("/");
leadzero(dayOfMonth);
Serial.print(dayOfMonth, DEC);
Serial.print("/");
leadzero(year);
Serial.print(year, DEC);
Serial.print(" ");
Serial.println(dayname[dayOfWeek-1]);
#endif
delay(1000);
}
void leadzero(byte val) {
if (val < 10) {
Serial.print("0");
}
}
#ifdef SETCLOCK
void setClock() {
//prompt for time settings
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
byte mode = 0;
byte ampm = 0;
char ans[1];
char dig2[3];
int serbytes=0;
Serial.println("Enter 2 dig year");
serbytes = getSerStr(dig2, 2);
year = atoi(dig2);
Serial.println("Enter 2 dig month");
serbytes = getSerStr(dig2, 2);
month = atoi(dig2);
Serial.println("Enter 2 dig day of month (1-31)");
serbytes = getSerStr(dig2, 2);
dayOfMonth = atoi(dig2);
Serial.println("Enter day of week where 1=SUN 2=MON 3=TUE 4=WED 5=THU 6=FRI 7=SAT");
serbytes = getSerStr(dig2, 1);
dayOfWeek = atoi(dig2);
Serial.println("Enter clock mode - 12 or 24");
serbytes = getSerStr(dig2, 2);
if (strcmp(dig2, "12") == 0) {
mode = Mode12;
Serial.println("Enter 'a' or 'p' for AM or PM");
serbytes = getSerStr(ans, 1);
if (strcmp(ans, "p") == 0) {
ampm = PM;
}
}
Serial.print("Enter 2 dig hour ");
if (mode == Mode12) {
Serial.println("(1-12)");
}else{
Serial.println("(0-23)");
}
serbytes = getSerStr(dig2, 2);
hour = atoi(dig2);
Serial.println("Enter 2 dig minute");
serbytes = getSerStr(dig2, 2);
minute = atoi(dig2);
second = 0;
if (mode == Mode12) {
bitSet(hour, 6);
if (ampm == PM) {
bitSet(hour, 5);
}
}
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.send(decToBcd(second)); // 0 to bit 7 starts the clock
Wire.send(decToBcd(minute));
Wire.send(hour); //already formatted with bits 6 and 5
Wire.send(decToBcd(dayOfWeek));
Wire.send(decToBcd(dayOfMonth));
Wire.send(decToBcd(month));
Wire.send(decToBcd(year));
Wire.endTransmission();
}
#endif
// Gets the date and time from the ds1307
void getClock(byte *second,
byte *minute,
byte *hour,
byte *dayOfWeek,
byte *dayOfMonth,
byte *month,
byte *year,
byte *ampm)
{
byte work;
byte mode; //12 or 24 hour
byte ap_ind; //am or pm indicator
// Reset the register pointer
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.endTransmission();
Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
// A few of these need masks because certain bits are control bits
*second = bcdToDec(Wire.receive() & 0x7f); //mask CH bit (bit 7)
*minute = bcdToDec(Wire.receive());
// *hour = bcdToDec(Wire.receive());
work = Wire.receive(); // get hour byte
mode = bitRead(work, 6); // if bit 6 set, running 12 hour mode
if (mode == Mode12) {
ap_ind = bitRead(work, 5); // if bit 5 set, time is PM
*hour = bcdToDec(work & 0x1f); // mask bits 5 thru 7 for 12 hour clock
if (ap_ind == PM) {
*ampm = 'P';
}else{
*ampm = 'A';
}
}else{
*hour = bcdToDec(work & 0x3f); // mask bits 6 and 7 for 24 hour clock
*ampm = ' ';
}
*dayOfWeek = bcdToDec(Wire.receive());
*dayOfMonth = bcdToDec(Wire.receive());
*month = bcdToDec(Wire.receive());
*year = bcdToDec(Wire.receive());
}
#ifdef SETCLOCK
int getSerStr(char line[], int lim) {
int bytesread=0;
int val=0;
Serial.flush();
while(bytesread<lim) {
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10) || (val == 13) || (val == '*')) {
break; // stop reading
}
line[bytesread] = val; // add the digit
bytesread++; // ready to read next character
}
}
line[bytesread] = '\0'; //terminate string
return(bytesread);
}
int getSerStrWait(char line[], int lim, int waitsecs) {
int bytesread=0;
int val=0;
unsigned long waitms = 1000 * waitsecs;
unsigned long start = millis();
Serial.flush();
while(bytesread<lim) {
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10) || (val == 13) || (val == '*')) {
break; // stop reading
}
line[bytesread] = val; // add the digit
bytesread++; // ready to read next character
}
if (millis() - start > waitms) {
Serial.flush();
line[0] = '\0';
return(0);
}
}
line[bytesread] = '\0'; //terminate string
return(bytesread);
}
#endif
//BCD to decimal conversion: decVal =(bcdVal.NIB1 * 10) + bcdVal.NIB0
//decimal to BCD conversion: bcdVal = (decVal / 10 <<4) + bcdVal // 10
// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
{
return ( (val/10*16) + (val%10) );
}
// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
return ( (val/16*10) + (val%16) );
}
// Stops the DS1307, but it has the side effect of setting seconds to 0
// Probably only want to use this for testing
/*void stopDs1307()
{
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.send(0x80);
Wire.endTransmission();
}*/
Thanks much for replying and providing the code...
I ran the code to see how it would work.. I entered 11:59 am and waited a minute or so... Then it rolled over to 04:00 am.... I reran the test several times - just to be safe...
I guess I might be missing something... I expected 12:00 pm....
Can you run the example and see if it does the same thing?
Hi... I'm still breaking my head over how to set the hour time 12/24...
I've tried various things including using 0x1f - but it doesn't effect the output... I still reports things back in military / 24 hours... I'm setting the time at 12:59 pm and then it becomes 13:00 instead of 1:00..
*hour = bcdToDec(Wire.receive() & 0x1f); //originally 0x3f
Please let me know what I am doing wrong...
Thanks much.
Here is the corrected code. When I was tweaking it, I forgot to convert from dec to bcd when setting the hour.
Good luck!
//clock SDA to analog pin 4 SCL to analog pin 5
#define DEBUG //compile serial monitor clock display
#define SETCLOCK //compile clock setup code
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68 //seven bit address
#define MAXLINE 10
#define Mode12 1
#define Mode24 0
#define AM 0
#define PM 1
static char *dayname[] =
{ "Sun",
"Mon",
"Tue",
"Wed",
"Thu",
"Fri",
"Sat"
};
void setup()
{
Wire.begin();
Serial.begin(9600);
#ifdef SETCLOCK
char ans[1];
int serbytes=0;
Serial.println("Enter 'y' to set clock");
serbytes = getSerStrWait(ans, 1, 10);
if (strcmp(ans, "y") == 0) {
setClock();
}
#endif
}
void loop()
{
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year, ampm;
getClock(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year, &m);
#ifdef DEBUG
leadzero(hour);
Serial.print(hour, DEC);
Serial.print(":");
leadzero(minute);
Serial.print(minute, DEC);
Serial.print(":");
leadzero(second);
Serial.print(second, DEC);
if (ampm != ' ') { //not space
Serial.print(" ");
Serial.print(ampm);
Serial.print("M");
}
Serial.print(" ");
leadzero(month);
Serial.print(month, DEC);
Serial.print("/");
leadzero(dayOfMonth);
Serial.print(dayOfMonth, DEC);
Serial.print("/");
leadzero(year);
Serial.print(year, DEC);
Serial.print(" ");
Serial.println(dayname[dayOfWeek-1]);
#endif
delay(1000);
}
void leadzero(byte val) {
if (val < 10) {
Serial.print("0");
}
}
#ifdef SETCLOCK
void setClock() {
//prompt for time settings
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
byte mode = 0;
byte ampm = 0;
char ans[1];
char dig2[3];
int serbytes=0;
Serial.println("Enter 2 dig year");
serbytes = getSerStr(dig2, 2);
year = atoi(dig2);
Serial.println("Enter 2 dig month");
serbytes = getSerStr(dig2, 2);
month = atoi(dig2);
Serial.println("Enter 2 dig day of month (1-31)");
serbytes = getSerStr(dig2, 2);
dayOfMonth = atoi(dig2);
Serial.println("Enter day of week where 1=SUN 2=MON 3=TUE 4=WED 5=THU 6=FRI 7=SAT");
serbytes = getSerStr(dig2, 1);
dayOfWeek = atoi(dig2);
Serial.println("Enter clock mode - 12 or 24");
serbytes = getSerStr(dig2, 2);
if (strcmp(dig2, "12") == 0) {
mode = Mode12;
Serial.println("Enter 'a' or 'p' for AM or PM");
serbytes = getSerStr(ans, 1);
if (strcmp(ans, "p") == 0) {
ampm = PM;
}
}
Serial.print("Enter 2 dig hour ");
if (mode == Mode12) {
Serial.println("(1-12)");
}else{
Serial.println("(0-23)");
}
serbytes = getSerStr(dig2, 2);
hour = decToBcd(atoi(dig2));
Serial.println("Enter 2 dig minute");
serbytes = getSerStr(dig2, 2);
minute = atoi(dig2);
second = 0;
if (mode == Mode12) {
bitSet(hour, 6);
if (ampm == PM) {
bitSet(hour, 5);
}
}
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.send(decToBcd(second)); // 0 to bit 7 starts the clock
Wire.send(decToBcd(minute));
Wire.send(hour); //already formatted with bits 6 and 5
Wire.send(decToBcd(dayOfWeek));
Wire.send(decToBcd(dayOfMonth));
Wire.send(decToBcd(month));
Wire.send(decToBcd(year));
Wire.endTransmission();
}
#endif
// Gets the date and time from the ds1307
void getClock(byte *second,
byte *minute,
byte *hour,
byte *dayOfWeek,
byte *dayOfMonth,
byte *month,
byte *year,
byte *ampm)
{
byte work;
byte mode; //12 or 24 hour
byte ap_ind; //am or pm indicator
// Reset the register pointer
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.endTransmission();
Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
// A few of these need masks because certain bits are control bits
*second = bcdToDec(Wire.receive() & 0x7f); //mask CH bit (bit 7)
*minute = bcdToDec(Wire.receive());
// *hour = bcdToDec(Wire.receive());
work = Wire.receive(); // get hour byte
mode = bitRead(work, 6); // if bit 6 set, running 12 hour mode
if (mode == Mode12) {
ap_ind = bitRead(work, 5); // if bit 5 set, time is PM
*hour = bcdToDec(work & 0x1f); // mask bits 5 thru 7 for 12 hour clock
if (ap_ind == PM) {
*ampm = 'P';
}else{
*ampm = 'A';
}
}else{
*hour = bcdToDec(work & 0x3f); // mask bits 6 and 7 for 24 hour clock
*ampm = ' ';
}
*dayOfWeek = bcdToDec(Wire.receive());
*dayOfMonth = bcdToDec(Wire.receive());
*month = bcdToDec(Wire.receive());
*year = bcdToDec(Wire.receive());
}
#ifdef SETCLOCK
int getSerStr(char line[], int lim) {
int bytesread=0;
int val=0;
Serial.flush();
while(bytesread<lim) {
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10) || (val == 13) || (val == '*')) {
break; // stop reading
}
line[bytesread] = val; // add the digit
bytesread++; // ready to read next character
}
}
line[bytesread] = '\0'; //terminate string
return(bytesread);
}
int getSerStrWait(char line[], int lim, int waitsecs) {
int bytesread=0;
int val=0;
unsigned long waitms = 1000 * waitsecs;
unsigned long start = millis();
Serial.flush();
while(bytesread<lim) {
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10) || (val == 13) || (val == '*')) {
break; // stop reading
}
line[bytesread] = val; // add the digit
bytesread++; // ready to read next character
}
if (millis() - start > waitms) {
Serial.flush();
line[0] = '\0';
return(0);
}
}
line[bytesread] = '\0'; //terminate string
return(bytesread);
}
#endif
//BCD to decimal conversion: decVal =(bcdVal.NIB1 * 10) + bcdVal.NIB0
//decimal to BCD conversion: bcdVal = (decVal / 10 <<4) + bcdVal // 10
// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
{
return ( (val/10*16) + (val%10) );
}
// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
return ( (val/16*10) + (val%16) );
}
// Stops the DS1307, but it has the side effect of setting seconds to 0
// Probably only want to use this for testing
/*void stopDs1307()
{
Wire.beginTransmission(DS1307_I2C_ADDRESS);
Wire.send(0);
Wire.send(0x80);
Wire.endTransmission();
}*/
Wow... It works great... I was able to modify my program as well... Thanks so much for the input!!!
RonC thanks for the excellent sketch, you have saved us a lot of time!