DS1307 Write Issues

[Suraj143]

Guys in my clock I use a DS1307 chip with PIC.The code works well.

I have two buttons to adjust the time "Hour" & "Minutes"

But sometimes I cannot write to DS1307.But it reads well.The display time is correct.

So after I remove battery & place it back I can write.

Whats the correct way of writing to DS1307?

I use SQW output also to interrupt @ 1 sec.

Do I need to turn off CH (clock Halt bit) or do I need to Stop SQW bit before writing to Hour or Minute registers?After writing registers I clear the seconds registers too.

 

[Pommie]

You shouldn't clear the seconds register. The correct way is to write all 8 registers in one go. The time gets written to the actual registers during the ACK. Note that the 8 writes must be in one block and written in less than 1 second.

Mike.

 

[Suraj143]

Hi mike I need only "Seconds","Minutes" & "Hour" registers.

If I need only above three do I still need to write all 8 registers?

I also show the seconds on the display.So I have to clear the seconds register after I change the time.

Currently I'm doing like this.
*Write Minutes
*Write Hours
*Write Seconds (clear)

You mean to write in this order?

*Write Seconds (clear)
*Write Minutes
*Write Hours

But in both ways the SQW register is operating (ON Mode).

 

[Pommie]

Yes, it should work writing seconds mins hours but they must be done in one write.

Mike.

 

[Suraj143]

Yes, it should work writing seconds mins hours but they must be done in one write.

Mike.

You got my point.Now Only I got it upto now I have written in separate writes that is bad.

I'll do in one write & see how it goes

Thanks for the idea.