Szia,
I am using this LED Matrix with backpack from Adafruit
https://www.adafruit.com/products/871
and this is how I wired it with the 3xAAA battery pack:
LED /…/Battery
VCC -> positive (red wire)
GND -> negative (black wire)
LED /…/RePhone GSM+BLE
SDA -> pin 1 (SDA)
SCL -> pin 2 (SCL)
The LED Matrix is fully functional, nothing is burned because when I have it connected to RePhone and I turn it off for a split second all the LED’s on the matrix are turning on (yellow), so it is functional.
I am afraid that RePhone got damaged since my pictogram’s are not drawn fully on the LED Matrix (only half side of them).
This is what I’m expecting to see for every button press (the pictogram will change)
and this is what I get actually on the matrix:
The matrix should show the full “smile” face but instead is displayng only half of it correct and the bottom half is always scrambled 
When I did this with Adafruit Flora or Gemma instead of RePhone I used this library (#include <TinyWireM.h>) but now with RePhone I can not because it gives this error message:
C:\Users\Catalin\Documents\Arduino\libraries\TinyWireM_master\USI_TWI_Master.cpp:23:24: fatal error: util/delay.h: No such file or directory
#include <util/delay.h>
so I am using #include <Wire.h> instead and I have no error at compile but maybe the library is the matrix display issue,
any suggestions?
Thanks!