RTCDS3231 setting Year

[manu68]

Hi to all,
I need a little help about year setup on RTC DS3231. I 'm using DS3232RTC Library
// GitHub - JChristensen/DS3232RTC: Arduino Library for Maxim Integrated DS3232 and DS3231 Real-Time Clocks.

I see on DS3231datasheet that Bit4, Bit5, Bit6, Bit7 should be the responsable bits for 10 year. I can set the Bit4 and Bit5 so I can obtain : 10 year(Bit4=1,Bit5=0) , 20 year ( Bit 4=0, Bit5=1) and 30 year (Bit4=1,Bit5=1) but How I can obtain 40 year? I mean the fourth decade or fifth and so on. I think I must use Bit 6 and Bit7 but doesn't works. What's wrong in my thinking ?

thanks

[markd833]

Posting your code would help here so we don't have to guess what you are trying to do .....

You mention setting bits, so I assume that you are using the writeRTC() function in the library, instead of the set() function? Any particular reason for this?

Does the SetSerial.ino example not do what you want?

[manu68]

HI Markd833,

thanks to your reply I checked once again the code and i found the error ... i was missed an "1" in the bitwise & (see bold line) . I put 0b00000011 instead of 0b00000111

Wire.beginTransmission(deviceAddress); //START, Roll Cal
Wire.write(0x00); //SEC Register address in Address Counter of RTC
Wire.write(0x00); //data for SEC Register (23 sec = 0010 0011)
Wire.write(0x00); //data for MIN Register (54 Min = 0101 0100)
Wire.write(0x00); //data for HRS Register for 12 hour clock time format 12:54:27
Wire.write(0x02); //Monday
Wire.write(0x20); //0001 1001
Wire.write (0x08); //Month : August
Wire.write (0x21); //year: 0001 1001 = 21---> 2021
Wire.endTransmission(); //Execute the above Tasks, ACK STOP
}

void loop()
{
showTimeOnLCD();
}

void showTimeOnLCD()
{
Wire.beginTransmission(deviceAddress); //START, Roll Cal
Wire.write(0x00); //set SEC Register address
Wire.endTransmission(); //Execute the above queued data, ACK, STOP

Wire.requestFrom(deviceAddress, 7); //SEC, MIN, and HRS to read from RTC as BCD
byte bcdSeconds = Wire.read();
byte bcdMinutes = Wire.read();
byte bcdHours = Wire.read();
bcdDay = Wire.read();
byte bcdDate = Wire.read();
byte bcdMon = Wire.read();
byte bcdYr = Wire.read();

//---show Time on LCD---------------
lcd.print("Time:");
lcd.print(bcdHours >> 4 & 0b00000001); lcd.print(bcdHours & 0x0F); lcd.print(':');
lcd.print(bcdMinutes >> 4); lcd.print(bcdMinutes & 0x0F); lcd.print(':');
lcd.print(bcdSeconds >> 4); lcd.print(bcdSeconds & 0x0F);
if (bitRead(bcdHours, 5) == HIGH)
{
lcd.print(" AM");
}
else
{
lcd.print(" PM");
}

{
//---show: day/month/year----
lcd.setCursor(0, 1);
lcd.print("Date:");
getDay(bcdDay);
lcd.print(dayOftheWeek);
lcd.print(" :");
lcd.print(bcdDate >> 4 & 0b00000011); lcd.print(bcdDate & 0x0F); lcd.print('/');
lcd.print(bcdMon >> 4 & 0b00000001); lcd.print(bcdMon & 0x0F); lcd.print('/');
lcd.print("20"); lcd.print(bcdYr >> 4 & 0b00000111); lcd.print(bcdYr & 0x0F);

}