I noticed that the SmartMatrix v4 takes 5v’s in but my Teensy 3.6 will only be able to take 3.3v (not 5v tolerant). I have seen people just stack the Teensy right on top of the SmartMatrix with headers, so does the SmartMatrix automatically shift the 5v it takes in down to 3.3v to use with the stacked teensy? Or will I need to buy a separate level shifter chip to manually shift the 5vs down to 3.3vs? Not sure exactly how that works.
As far I know, SmartMatrix shield doesn’t outputs any signals to the Teensy so you don’t need a level shifter in that direction. Any signals transmitted only in opposite direction - from the Teensy to Smartmatrix.
Would it work to supply both the SmartMatrix and Teensy with the same 5v power supply though? I suppose thats the main concern since the Teensy 3.6 is not 5v tolerant
The Teensy has a 3.3V regulator on board, so when you supply the board with 5V the chip only gets 3.3V.
There’s more detail on the SmartLED Shield’s power circuit here: SmartLED Shield V4