Datasheet

Changing I2C Address

The HT16K33 driver chip on these LED backpacks 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 2 or 3 address adjust pins, so that the address can be changed! The mini 0.8" 8x8 matrix

backpack has 2 address adjust pins. The 1.2" 8x8, bi-color 8x8, bi-color bargraph and 4 x 7-segment backpacks have 3

address adjust pins.

That means that you can set the backpacks to these addresses:

Mini 0.8" 8x8: 0x70, 0x71, 0x72, 0x73

Small 1.2" 8x8: 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77

4 x 7-segment: 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77

Bi-color 1.2" 8x8: 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77

Bi-color 24-bargraph: 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77

You can mix-and-match matrices, as long as each one has a unique address!

Changing Addresses

You can change the address of a backpack very easily. Look on the back to find the two or 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

A2 does not appear on the mini 0.8" 8x8 matrix, so you cannot set the address higher than 0x73

On the 1.2" 8x8 backpacks, the labels for A1 and A2 are swapped! Sorry about that!