RTC real time clock for the Pi
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RTC real time clock for the Pi

by pennypacker on Sat Oct 06, 2012 3:20 am

I am trying to install the RTC module for the raspberry pi.

I think I have followed the instruction from adafruit correctly. I left off both resistors. Then, I hooked it up according to the pinout instructions and when I first booted, I was able to get the 68 in the little table by running i2cdetect to show that the system was recognizing it. However, by the time I went through the rest of the instructions, it was already not working, the system said something about not being able to access the hardware clock. so I ran i2cdetect again and it was not showing up. I tried rebooting, and saw it there again for a moment, then ran it again and it was gone. I have unhooked and rehooked everything into the gpio pins of the rapi with no luck. Now I can't get i2cdetect to recognize it at all. I am using the 5v pin on the rpi as I think the instructions say to do that (they are a little fuzzy in some places).

Any ideas? Has anyone had any trouble with these failing?
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Re: RTC real time clock for the Pi

by MrZhi on Tue Oct 09, 2012 11:54 am

I used the adafruit breakout for DS1307 with great success on my Pi. I also have the GPIO breakout board for the Pi as well, so that made it a lot more clear when connecting the pins. Honestly, if I had to guess, I would say that you need to check to see if the module is still loaded on your PI and check the physical connections again, or even post a picture of your setup for some extra clarity into your problem.
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Re: RTC real time clock for the Pi

by pennypacker on Thu Oct 11, 2012 1:09 am

What do you mean "check to see if the module is still loaded"?

I will try to post some pics tomorrow of my setup. I have checked and rechecked and I am pretty sure it is setup correctly. Especially since I am getting the 68 showing in the table off and on now. It will show for a bit, then after a few seconds I will run the i2cdetect again and it will be gone.
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Re: RTC real time clock for the Pi

by pennypacker on Thu Nov 15, 2012 2:33 pm

After much trial and error, I finally discovered that my rtc was defective. I now have another and installation was a breeze. I have gone through the instructions provided on adafruit to install the real time clock on the raspberry pi. I can successfully push the time to the rtc from the system time using sudo hwclock -w I can also read the time off the rtc with sudo hwclock -r However, the last thing I am having difficulty with is getting the raspberry to automatically sync to the rtc on bootup. It continues to use the fake hwclock and seemingly ignores the rtc. I have tried lots of things included a rather complex set of instructions on a forum post at raspberrypi.org. None seem to work. After making changes, I have started from a fresh install each time to avoid confusion. This time, I have followed the tutorial exactly. I tried as is, and I also tried modifying it a bit and putting rtc-ds1307 rather than rtc-1307 into the modules file.

Has anyone here had success setting up the rtc from adafruit using the tutorial on the site? I am using the occidentalis 0.2 image. any more help would be much appreciated.
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Re: RTC real time clock for the Pi

by pennypacker on Thu Nov 15, 2012 4:04 pm

SOLUTION!

After a month of on and off trying to get the rtc to work on the ra pi with occidentalis 0.2, I ended up following the instructions listed in the tutorial by adafruit and then adding "sudo hwclock -s" in the rc.local file right after the "echo ds1307..." statement. This seems to work fine. I'm sure there may be some issues if some programs load before that, but this is a good enough solution for me. Perhaps some more expert linuxers could elaborate on whether this is an ok solution or not... but all I know is that my ra pi is syncing time to the real time clock on boot.
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