Unused Pins on the RGB Matrix Backback?

[b34npour]

I know that when you manually wire an Arduino Uno to the RGB Matrix you are left with digital pins 11, 12, 13 and analog pins 4, 5 to use with other sensors. Are these pins still available on the RGB Matrix Backpack?

The reason I ask is because this isn’t mentioned on the description page and the physical board doesn’t appear to have these pins.

[Michael]

Correct, analog pins 4,5 are not used, and digital pins 11,12,13 are not used. Digital pin 10 is connected to the button.

However the pins are not broken out to pads, so you’d have to solder directly to the ATmega328 chip’s pads to use these pins. I should have broken out these pins to pads 🙁

[b34npour]

Awesome, that’s what I was hoping for. I don’t have a problem with soldering a breakout cable or something directly to the ATmega328 😉

[b34npour]

One more quick question: What would be the appropriate pin to solder a ground connection to? I’m setting up an I2C connection between two Arduinos (one being the Backpack) which requires that their grounds be connected (along with analog pins 4 and 5 too, but I know where those are).

Should I just solder to pin 8 or 22 on the ATmega328’s pads?

[Michael]

One of the terminal block connections is ground (labeled GND), and the big fat connection directly underneath the power jack is also ground. All the grounds are connected, so you can choose any of them.

[b34npour]

Just soldered it up, thanks Michael!

[chrishem]

Are the pins which provide SPI available?
I believe (but could be incorrect) that those are MOSI (PB3 / pin 17), MISO (PB4 / pin 18), SCK (PB5 / pin 19) and _SS_ (any GPIO I think?).
Alternately, what about the TX and RX pins?

Essentially, I’m trying to come up with a good way to get data into and out of the Nootropic backpack.

Thanks!

[simon_schvartzman]

Hi team, I would like to connect the backpack to an Arduino Yun.

Ideally I would like to use the Yun’s USB port connected to an FTDI cable on the backpack.

Any ideas?

Many thanks in advance

[eriknauman]

To update this topic to the V2 backpack, since the onboard button was moved from pin 10 to pin 11 can I assume the unused digital pins are 10, 12, and 13?
And the analog pins are 4 & 5?
Thanks,
Erik

[Michael]

Pin 10 is not available as it is also used to control the matrix. Pins 12 and 13 are available and analog pins 4 and 5.

[eriknauman]

Thanks!
I’m trying to connect a hover (V1 http://www.hoverlabs.co/shop/hover-original) gesture control and have every pin needed on the Atmega for the hover but am missing a 3V+ line. Is there one somewhere on the backpack, like there is on an Arduino UNO?

[Michael]

The backpack doesn’t have a 3.3V line. An Arduino has one because the FTDI USB adapter chip provides a 3.3V line.

[Author]

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