Discussion in "Project Help" started by    rshankar    Feb 7, 2007.
Wed Feb 07 2007, 09:55 pm
I have made the subject mentioned project.I am not able to get the desired result.
The LCD is showing the day"SAT" anly and the digits for time and date are blank. It is just showing the constants like / / and : :.
I have reckecked all the hardware connections and the codes( downloaded in asm). I could n't find any thing wrong.

Kindly suggest the probable causes of defects and what are the points for further checking.
Thu Feb 08 2007, 02:53 am
The possible problem maybe with the RTC.. or its connections.. please recheck the connection and pins used for RTC with controller.
There should not be any problem of such kind.. is everything else ok? i mean.. when you power up?
is there any wrong you find? or just this problem?
Fri Feb 09 2007, 06:32 pm
The clock started working.After some time I switched off power supply and after few miniutes again switch on the power supply. the clock did not work. The date and thime was blank. It seems that problem takes place after switching on power supply I have following doubt:
As per the data sheet of DS1307 the bit 7 of register 0 is clock halt. The oscillator is disabled when this bit is 1 furit is written that on initial power on the the state opf all registers is not defined.Therefore it is important to enable the oscillator during initial configuration.
How ever in your program (assembly language) this enabling of oscillator is not given.
This is my doubt and I did not mean that your program is wrong. Pl send me you comments.
Fri Feb 09 2007, 06:54 pm
Well clearing your bout, when you run your RTC for the first time it will write the default values in the registers, i am writing 0x00 in register 0 that mean... no problem with clock halt.
When you power off the clock, the backup battery is there with the RTC which will retain the data.. that means if the CH bit of Reg0 is cleared then there is no chance that clock gets halted

and if the clock is halted the seconds will come as 80.. if you are getting the display as 80 then clock is halted but in your case no display so some other problem.
Thu Feb 15 2007, 09:32 pm
Thanks for the comments. the clock has started working and I got the display in the LCD. The problem was with the hardware i.e. loose connection. but today againg the same problem took place i.e. after switching off and then again switching on the clock stopped and the seconds was showing 82.I have connected battery also and it's voltage is 3.32 V that means battery is charged. I am not able to understand that how seconds reached to 82.
Thu Feb 15 2007, 09:41 pm
it happen sometimes.. i think you should not do fast break and make of circuit.. i mean.. sudden switch off then on.. problem will not come then..

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