You can tile up to eight Trellis PCBs on a single 2-wire I2C bus. This allows you to easily build up to 8x16 or 4x32 panels which can be lots of fun!

To start with, its a good idea to assemble and test each individually so you know each Trellis works individually.
There's little nubs on the sides of some PCBs that keep them on the assembly panel, you can file them off with any file or sandpaper.
Arrange the tiles up the way you want, we'll start with two. Make sure the Adafruit logo is lined up the same.
Solder two blobs of solder on two adjacent finger pads.
Use your soldering iron to drag solder from one pad to another, with a little effort they'll stick together and make a connection. You can add more solder to make the connection stronger. Its still not mechanically strong - so be careful not to bend or shake the arrangement

For a more robust connection, use a small bare wire across the pads instead of just solder. The legs trimmed off the LEDs are perfect for this!

Repeat for the other 4 fingers
Check that the panels are aligned by looking from the side, gently bend/reheat until they are nice and straight
You can add a little more mechanical stability by soldering the large front tabs as well
Repeat for up to 8 panels connected together, in any arrangement you like


Each Trellis tile must have a unique address. You can set the addresses on the back of each panel using a little solder over the address jumpers.

The HT16K33 driver chip on the Trellis has a default I2C address of 0x70. Since each device on an I2C bus must have a unique address, its important to avoid collisions or you'll get a lot of strange responses from your electronic devices!

Luckily, the HT16K33 has 3 address adjust pins, so that the address can be changed. Each pin changes one binary bit of the address, so you can set the address to any of the following (in hex) 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77

The panels don't have to have consecutive address #'s, they just have to be unique.

Changing Addresses

You can change the address of very easily. Look on the back to find the three A0, A1 or A2 solder jumpers. Each one of these is used to hardcode in the address. If a jumper is shorted with solder, that sets the address. A0 sets the lowest bit with a value of 1, A1 sets the middle bit with a value of 2 and A2 sets the high bit with a value of 4. The final address is 0x70 + A2 + A1 + A0. So for example if A2 is shorted and A0 is shorted, the address is 0x70 + 4 + 1 = 0x75. If only A1 is shorted, the address is 0x70 + 2 = 0x72

For example, this Trellis has A0 shorted, the address is 0x71
This one has A1 shorted, the address is 0x72
If both A0 and A1 are shorted, the address is 0x73
If A2, A0 and A1 are shorted, the address is 0x77
Once you have set the unique addresses, you can set the addresses in the Arduino code, see the software page for details on how to do it.

This guide was first published on Dec 06, 2013. It was last updated on May 20, 2024.

This page (Tiling) was last updated on Mar 08, 2024.

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