AT89C52 with DS1307

[Rajagopal]

My name is Rajagopal 70 years old, I knows basic electronics but no experience in current programming.

           I have purchased a few 7 segment 4 digit with AT89C52, RTC DS1307, 74LS595 (4nos), and ULN 2003 (4nos)  12hrs format and program preloaded assembled clock PCBs.

I did 12” , and 15” height and 4’ long LED display with driver circuits, this clocks are working since 2- 3 years, with Accuracy and good condition.

            I made a another display for another clock board, but my soldering mistake it was not work , found the fault and modified it and found working  3 digit only, the 4^th digit of 10hrs digit not work, I mean, run from 0 : 0 0 to 9 : 5 9 after 9 : 5 9 it is not going to 1 0 : 0 0 instead 1 0 : 0 0 it is going again 0 : 0 0 (three digits zeros) and run up to 9 : 5 9 then again  going 0 : 0 0 and run up to 3 : 5 9, after 3 : 5 9 it is going to 0 :  0 0 it mean, it is working as 10hrs + 10hrs + 4hrs for 24hrs, instead 12hrs format (12hrs + 12hrs  = 24hrs).

            Removed DS1307 ic and replaced a new DS1307, but working as above. Not only one, few new DS1307 ics replaced but same as above. 

           Now I doubt in AT89c52, what happened changed the program code in the AT89C52 it self, may it will possible?.

            Circuit and program are designed with AT89C52 for 12 hrs format earlier it was worked I assembled  two clocks still it is working, some unknown reason RTC  DS1307 is changed to 10hrs + 10hrs + 4hrs for 24 hrs format why?, and how to get it back to 12hrs format, may any one help me, please. 

[SHAH DISHANT H.]

Hi,

 

We respect your eagerness to learn at this age.

 

This problem sounds amazing. Can you please post code and schematic so that we can try to solve issue?

[Rajagopal]

 

Thanks for your reply

 

I dont know the code because it is preloaded program,

 

schemetic

 

 

 

 

Thanks,

krgopal

 

 

[Rajagopal]

Thanks Mr.  for your reply,

 

I dontknow the code, it was preloaded program, and I read out from 89c52 it is in HEX file.

 

 

KRGopal  –  abiamarayahoo

schemetic 

 

wysiwyg_imageupload:11833:

 

 

[SHAH DISHANT H.]

Well, we can not help without code as everything is on programming.

 

If required, we can give a try on developing code.

[Ganesh Selvaraj]

Hello Mr. Rajagopal,

 

According to what you have written I don’t think there is any problem with the programme in the micrcontroller. You said that your 4th 7-segment display is not working well but you fixed it. Now what does that display show when the hours is in single digit? (I mean does is show 0 9 : 5 9 ?) and what does it show after 9 : 5 9?

[Rajagopal]

Mr. Ganesh Selvaraj,

 

According to what you have written I don’t think there is any problem with the programme in the micrcontroller. You said that your 4th 7-segment display is not working well but you fixed it. Now what does that display show when the hours is in single digit? (I mean does is show 0 9 : 5 9 ?) and what does it show after 9 : 5 9?

 

 

No, 0 : 0 0 (three digits zeros only) the 4th digit of 10s hrs digit  not working, after 9 : 5 9 it is not going to 1 0 : 0 0, instead 1 0 : 0 0 it is going again 0 : 0 0 (three digits zeros only 4th digit not lightup ) and run up to 9 : 5 9 then again  going 0 : 0 0 and run up to 3 : 5 9, after 3 : 5 9 it is going again to 0 :  0 0 it mean, it is working as (0:00 to 9:59 two times and 0:00 to 3:59 one time) 10hrs + 10hrs + 4hrs for 24hrs, instead 12hrs format (12hrs + 12hrs  = 24hrs).

 

Thanks,

 

Rajagopal.

[Rajagopal]

Dear all,

 

Now I found the problem, now it is working as usual, I did in reset pin number 9 of AT89C52 just touch a wire with 5 volt positive  3 – 4  times now it is work as 12hrs format, after (0) 9 : 5 9 it is going to 1 0 : 0 0 and as usual, I mean that 4th digit of 10hrs digit is working, I think this happen is reset problem (why, I don’t know), This circuit is already having reset circuit that is one 10mfd capacitor connected with 5 volt positive and one 10 k resistance is connected with ground.

 

And I am having another one problem in it, that, when touch with a metal piece (forceps or naked screwdriver) in any (positive or negative) pins of any ICs in this circuit, suddenly changes going in the display digits I mean, some segments are, on or / and off (Random) its self, after fraction of seconds it is back to normal, working OK, why this happen, this circuit have connected a 100 N disc capacitor in each 74LS595 ICs vcc to with ground.

 

Thanks.

[Author]

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