Toying with concepts here. I’ve got a TM1638 (great for I/O!) installed on my Rover V2. I’ll probably mount a MMA7361 Angle Sensor next , so I’ll soon be running out of pins for a few other ideas.
I see the I/O Expansion Shield for Arduino v7 has a dedicated I2C Interface.
How do I connect it to a 2nd Arduino … let’s say UNO ?
Thanks.
My question is not programming related but hardware related directly applicable to the V7 Shield.
As seen here dfrobot.com/wiki/index.php/File:DFR0265_Pinout.png the I2C Interface has 4 connections 5V, GND, SCL, and SDA.
How do I connect them to an UNO? For example… the two pins of the V7 SDA connect to …? on the UNO, etc
Another question that comes to mind is if the UNO also had a V7, would it be a simple 1-1 connection? … 5V to 5V, GND to GND, SCL to SCL and SDA to SDA.
A4==SDA and A5==SCL… but the V7 SDA/SLC interfaces each have two pins. So I just connect either one of them over to the other board?
Because of the two pins I was just worried about some +/- scenario I’m not aware of.
Great. Thank you.
I’m going to have fun with this Rover 
Depends on what you want to do - you can use many different ways to communicate between two Arduino boards including serial, I2C, analog, digital etc.
For the uno “A4 or SDA pin and A5 or SCL pin”, and of course connect the common ground. If you want to power the second Uno from the first board, you can try to connect the 5V line as well.
The two sets of four pins allows you to connect one device and then connect to another. The big advantage to I2C is connecting many devices using the “same” cables.
