data logger couldn't find RTC

[mikem33]

For several years I have had two of the original version data loggers with DS1307 RTC. These work fine.

I just received from Amazon one of the newer version B Adafruit data loggers with PFC8523 RTC. Consistently I get an error "Couldn't find RTC."

I installed stacking headers and double-checked for shorts. Solder joints are clean. I installed the 2x3 header for ISPC, connection is good. I have loaded the latest RTClib ver 2.01. Also tried several older versions of RTClib but no help. I have tried uncommenting various combinations of "rtc.adjust" lines in the "pdf8634" sketch but still get same error. Sketches upload with no problem. Baud rates were adjusted correctly in each case for the serial monitor.

Also tried running the "light-temp-logger.ino" from github. Serial monitor reports that SD card initialized and begins logging to the card but says "RTC failed".

I have tried all these things on several of my Arduino Uno R3's and on an Arduino Mega 2560 with same result. I have not shorted or cut any of the pads on the data logger bottom side.

I am out of ideas about how to find the problem. What can you suggest to try next?

[adafruit_support_carter]

Does the RTC address show up in an I2C scan?
https://learn.adafruit.com/scanning-i2c ... s/overview

[mikem33]

Thank you for quick reply!

i2c_scanner below reports:
https://learn.adafruit.com/scanning-i2c ... es-arduino

"Scanning...
No I2C devices found"

[adafruit_support_carter]

It might be a connection issue then. Please post a photo of your setup showing how everything is connected.

[mikem33]

Picture as requested. Nothing wired except leads for onboard LEDs.

[mikem33]

Also here is other side of logger board

[adafruit_support_carter]

Thanks for the excellent photos. I think you just need to solder on two more header pins here:

shield.jpg (83.98 KiB) Viewed 1109 times

This was part of the design change for the two versions you are dealing with.
https://learn.adafruit.com/adafruit-dat ... and-config

Since SCL/SDA are no longer connected to A4/A5 by default, you'll want to add the extra pins. Your UNO looks like a version that will have the I2C pins in those locations, so should just work once those pins are in place.

If you really want to use A4/A5, then you can solder the jumper pads closed on the back of the shield:

pads.jpg (35.42 KiB) Viewed 1109 times

[mikem33]

Looks like I needed a 10-pin stacking header on that side instead of an 8. Not sure how I missed that.

Thanks a bunch for your help!