Official mods to Adafruit 1411 rtc/logging shield for Mega2560?

Development Tools IDE 1.x
1

Hello,

I'm about to try modifying pin connections to an Adafruit 1411 logger shield so it will work properly on a Mega2560.

It worked fine on a Uno before.

There are a few scattered articles on the subject, but is there an official document on how to properly achieve this please?

EDIT: I've found an article on modifying the SD library, so the 1411 logger shield can work on a Mega, at Older Datalogger Shield Leonardo & Mega Library | Adafruit Data Logger Shield | Adafruit Learning System ... BUT, the example is for arduino 1.0.3, and I am using 1.6.3 which has a slightly different folder structure. I hope this doesn't cause problems.

Thanks,

Matt

2

There is this official part about using the SD card:

For the RTC the tutorial says:

"The RTC is an i2c device, which means it uses 2 wires to to communicate. These two wires are used to set the time and retreive it. On the Arduino, the pins are 'fixed' to be Analog 4and** 5** for the built in i2c capability. This is a bit annoying since of course we want to have up to 6 analog inputs to read data and now we've lost two. There is a way to use other pins...however, the hardware is by default set up for Analog 4 and 5 so lets start with that and then later we'll show how to modify the shield!"

Unfortunately that "later" never seems to arrive. Presumably they would tell you to cut the traces between the SDA/SCL pads and A4/A5 pins then jumper the SDA and SCL pads to the I2C pins appropriate for your board. On the MEGA 2560 that would be the two pins nearest the USB connector (see the back of the board for the labels).

3

Thanks for your support.

I carefully followed all the instructions at the link below, and that seems to make the Adafruit 1411 shield work fine on the Mega2560, with no pin changes! :slight_smile:

I'm using the first 4 analog inputs (0-3) with no obvious problems.

Regards,
Matt.

4

protomoose:
I'm using the first 4 analog inputs (0-3) with no obvious problems.

I guess it already uses the dedicated SCL and SDA pins as well as the A4 and A5 pins. That should work on recent boards (MEGA 2560, UNO R3, Leonardo) as long as you don't need A4 or A5 for anything. On the MEGA and Leonardo you can use A4 and/or A5 for analog input or digital I/O if you cut the shield traces linking them to SCL and SDA. You only need those traces intact on the UNO R2 and earlier models.