Description:
You must connect SDA to A4 and SCL to A5 in order to get the RTC to work.
SDA and SCL are the last two pins next to the reset switch on the board, A4 and A5 are the last two pins at the opposite corner of the board. There are convenient solder points right next to each pin on this board.
SCL and SDA are also available on pins 20 & 21 on the Mega board, you can use jumpers to A4 & A5 on the data logger board.
This is an R3 version shield, but since it doesnt have an ICSP jack, it wont work interchangeably with the MEGA 2560 R3, without modifying things. Also, this card uses Pin 10 for SD, not the default pin 4 that the Arduino SD library defaults too. Once thats changed, the SD card functions with the library.
A plus is the clock. It works well. The SD library doesnt support writing a date (from the RTC) automatically. You need to add a clock call-back function to the loop(), and associate it correctly, during setup. Once thats done, it works very well.
This is an R3 compatible, so it includes the SDA and SCL pins. They are also broken out so they are easy to use. it a useful shield and have incorporated it into an automatic SD temperature logging sensor project.
Packing List:
4 * Data logger module