PR 12 REAL TIME CLOCK ..

[TeoYX]

Hi all,


I encounter the real time clock problem with change value and clock running again. I use the same program and same circuit i tested OK last time but now it cannot work totally. The LCD display all 0 and unable to save the value i changed. The clock also not running at all no matter how long i power ON it.

Does anyone face this problem as me before? How do i troubleshooting further? I did check connection and it is correct. Program able to be compiled with no error as well. I totally lose in this point... Please help if anyone know.

Hope can get any suggestion. Thanks a lot.

[TeoYX]

How do i test the DS1307 whether it is working properly or not? Any testing method i can try on the IC?

Please advice. Thanks.

[ABSF]

Hi all,


I encounter the real time clock problem with change value and clock running again. I use the same program and same circuit i tested OK last time but now it cannot work totally. The LCD display all 0 and unable to save the value i changed. The clock also not running at all no matter how long i power ON it.

Does anyone face this problem as me before? How do i troubleshooting further? I did check connection and it is correct. Program able to be compiled with no error as well. I totally lose in this point... Please help if anyone know.

Hope can get any suggestion. Thanks a lot.

Your circuit was working once and doesnt work now, correct? To do trouble-shooting, you have to isolate the fault part by part or block by block.

1. Is you circuit constructed on PCB or breadboard?

2. Is your PIC & LCD confirmed working?

3. If you have a scope or logic probe, you can monitor the SDA & SCL lines. Are there any pulses from PIC to 1307 and vice versa? There should be some activities when the clock is updating the PIC every second or every minute or during the setting of clock.

4. Is the +5V and battery voltage for clock OK?

There are many things you can check besides the software (which I dont suspect as it was working before). The keyword is ISOLATION of fault....

Allen

[TeoYX]

Hi all,


I encounter the real time clock problem with change value and clock running again. I use the same program and same circuit i tested OK last time but now it cannot work totally. The LCD display all 0 and unable to save the value i changed. The clock also not running at all no matter how long i power ON it.

Does anyone face this problem as me before? How do i troubleshooting further? I did check connection and it is correct. Program able to be compiled with no error as well. I totally lose in this point... Please help if anyone know.

Hope can get any suggestion. Thanks a lot.

Your circuit was working once and doesnt work now, correct? To do trouble-shooting, you have to isolate the fault part by part or block by block.

1. Is you circuit constructed on PCB or breadboard?

2. Is your PIC & LCD confirmed working?

3. If you have a scope or logic probe, you can monitor the SDA & SCL lines. Are there any pulses from PIC to 1307 and vice versa? There should be some activities when the clock is updating the PIC every second or every minute or during the setting of clock.

4. Is the +5V and battery voltage for clock OK?

There are many things you can check besides the software (which I dont suspect as it was working before). The keyword is ISOLATION of fault....

Allen

Thanks Allen,

1. The circuit is in PCB.
2. My PIC is working when i use for another project. The LCD display also working well with the same PIC.
3. I need to try this on Monday only. I have no equipment on my hand now.
4. The 5V and battery is OK for RTC.

Do you have other idea about the troubleshooting?

Thanks a lot.

[ABSF]

pr12 simulated

I simulated PR12 on proteus with the scope showing SDA and SCL signals.

Since you said you PIC and LCD and codes were confirmed good. And If you're not getting the signals that I got, then most probably either the DS1307 or the crystal is the most suspected. Did you put any 0.1uF caps on the +5V and before the 7805 DC lines? The circuit is so simple, I only spent less than half an hour on the proteus. What other components do you want to suspect?

Allen

[TeoYX]

I follow the connection from the Project 12 schematic for the LM7805 and RTC IC. There is using 100uF cap. Is that OK? Do i need to change it to 0.1uF cap?

Please advice. Thanks.

[ABSF]

No, I mean add 0.1uF (100nF) parallel with 100uF. 100uF is for 50Hz filtering while 100nF for noise produced by PIC working at high frequency.

Allen

[Idris]

is it possible if i want add some features on this PR12? like make from normal clock to multiple alarm clock? and may be some output? any changing on hardware? what method in programming i need to do to add this features?

I think you need to modify the program, try to compare the time to multiple set point.