You can tile up to 32 NeoTrellis PCBs on a single 2-wire I2C bus. This allows you to easily build up to 16x16 larger panels which can be lots of fun!

To start with, its a good idea to assemble and test each individually so you know each NeoTrellis works individually.

The photos below show the earlier non-Neo Trellis but the process is identical for NeoTrellis!

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.

On the other side make sure LEDs #1 are in the same corner

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

Repeat for the other 4 fingers

Addressing

Each NeoTrellis 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 seesaw driver chip on the Trellis has a default I2C address of 0x2E. 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 seesaw has 5 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 hex number between 0x2E and 0x4E inclusive

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, A2, A3 and A4 solder jumpers.

Each one of these is used to hard-code 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 bit with a value of 2
  • A2 sets the bit with a value of 4
  • A3 sets the bit with a value of 8
  • A4 sets the bit with a value of 16

The final address is 0x2E + A4 + A3 + A2 + A1 + A0. So for example if A2 is shorted and A0 is shorted, the address is 0x2E + 4 + 1 = 0x33

Address Cheat Sheet

If you take on a project using many NeoTrellis boards, here's a handy cheat sheet for address/jumper value combos:

Download: file
(default)             0x2E
A0 (+1)               0x2F
A1 (+2)               0x30
A2 (+4)               0x32
A3 (+8)               0x36
A4 (+16)              0x3E

A0+A1 (+3)            0x31
A0+A2 (+5)            0x33
A0+A3 (+9)            0x37
A0+A4 (+17)           0x3F

A0+A1+A2 (+7)         0x35
A0+A1+A3 (+11)        0x39
A0+A1+A4 (+19)        0x41

A0+A1+A2+A3 (+15)     0x3d
A0+A1+A2+A4 (+23)     0x45
A0+A1+A2+A3+A4 (+31)  0x4d

A0+A2+A3 (+13)        0x39
A0+A2+A3+A4 (+29)     0x4b
A0+A2+A4 (+21)        0x43
A0+A3+A4 (+25)        0x47

A1+A2 (+6)            0x34
A1+A3 (+10)           0x38
A1+A4 (+18)           0x40
A1+A2+A3 (+14)        0x3c
A1+A2+A3+A4 (+30)     0x4c
A1+A3+A4 (+26)        0x48

A2+A3 (+12)           0x3a
A2+A4 (+20)           0x42
A2+A3+A4 (+28)        0x4a

A3+A4 (+24)           0x46

Thanks to Okyeron on the Lines forum for creating this list.

Here's an example of address jumper settings for an 8x8 grid from Okyeron:

This guide was first published on Sep 20, 2018. It was last updated on Sep 20, 2018.

This page (Tiling) was last updated on Nov 06, 2020.