Interface of DS1307 with PIC16F876A

[Eng4444]

i think you didn't understand me well because you provided me a program to read from DS1307 and i am thankful.

But still, i dunno how to prgram it ( i mean how to set hours, minutes, seconds, month, day ,year for the first time).

So as i said, i just bought a DS1307 and i have a PIC16F876A. what are the next steps?....


I'll appear an idiot i know but really... this is not my field at all.. i got stuck with it and not way to step back because of lack of time...

thank you all for your understanding.

[Eng4444]

Would you be able to help me?

[Charles Linquis]

The following may prove useful.

Remember that the DS1307 stores all data in BCD format, so you will have
to convert your ASCII input into binary BCD before writing, and will have to
convert back from BCD when reading.


ClockAddr CON %11010000 ' RTC device address (byte addressing)
Offset CON 0
Cntrl CON %00010000 ' sets the SQW/OUT to 1Hz pulse, logic level low

I2CRead SDA_PIN, SCL_PIN,ClockAddr,Offset,[sec,mins,hr,day,date,mon,yr],ErrorTrap


I2CWrite SDA_PIN,SCL_PIN,ClockAddr,Offset,[sec,mins,hr,day,date,mon,yr,cntrl],ErrorTrap

[Travin77]

If you can buy a ds1302 RTC I can provide you with a working program and a schematic. I know it isn't a 1307, but those are the options I can provide.

Travin

[Eng4444]

If you can buy a ds1302 RTC I can provide you with a working program and a schematic. I know it isn't a 1307, but those are the options I can provide.

Travin

++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++

I do not care about the IC, i can buy DS1302 as long as it gives the same result.
i just need to deal with time in a certain way (multiply, divide...etc) so the IC will not cause a prob at all... do you have a program for PIC16F876A? i'll be more than thankful!!!

[Melanie]

Eng4444 please understand that folks don't sit next to their terminals all day long waiting to answer your questions. I might glance at it once a day if I'm at my desk - sometimes more, or I might not for several days at a time... Time may be of the essence for you but I also have other priorities in my life...

If you are calculating Energy = Power . Time, then you are about to open up a whole heap of time calculation problems if you are going to read the time and date, because as you move through midnight into the next day, or increment through into the next month, you have to take into account a whole new set of figures...

Example... What is the elapsed time between 14:37:31 on 25/02/06 and 17:11:09 on 26/05/06? That's a whole heap of code to do that. You have to work out how much time elapsed until midnight on one day, and how much time elapsed since midnight on the next. Then a month goes by... and you have to take account how many days have elaspsed. And was this year a Leap Year? If you get it wrong you're a day out... So unless you convert everything to Linear Time (there was a long thread on Julian Date calculation some time ago) you have a headache with a PIC full of lots of code doing no more than calculating an elapsed period.

The DS1307 however provides you with an easier solution that saves you having to do these Time and Date calculations... just count Seconds. Set up the DS1307 to output a Second Pulse to your PIC, and your program sits there doing whatever you want it to do and just simply incrementing a counter every time a Second ticks by.

Melanie

[Archilochus]

Isn't there a different chip in the DSxx series that just records the launch date and then counts elapsed seconds? - can't recall the part # off-hand.

Arch