Chained I2C Devices with Same Addresses using the STEMMA QT connectors

For Adafruit customers who seek help with microcontrollers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
fiewfweifweoifnwnefonwef
 
Posts: 1
Joined: Tue May 23, 2023 3:42 pm

Chained I2C Devices with Same Addresses using the STEMMA QT connectors

Post by fiewfweifweoifnwnefonwef »

Hello,

I am currently using the Adafruit FT232H and the Adafruit APDS9960 STEMMA Qt / Qwiic.

Order No.: 3072418
Ordered: 05/16/23

I am trying to connect ~40 of the Adafruit APDS9960 together in a chained fashion using their STEMMA QT connectors (on either side of the sensor board) and having one of the ends of the chain plugged into the FT232H to receive the data.

From what I have been able to gather, the addresses on the APDS9960 are not able to be changed in software or physically with bridging pins.

I am aware of the Adafruit TCA9548A 1-to-8 I2C Multiplexer, but wanted to avoid using them due to the sizing, timing, and physical constraints of my project.

Thank you.

User avatar
adafruit_support_mike
 
Posts: 67391
Joined: Thu Feb 11, 2010 2:51 pm

Re: Chained I2C Devices with Same Addresses using the STEMMA QT connectors

Post by adafruit_support_mike »

fiewfweifweoifnwnefonwef wrote: Tue May 23, 2023 3:57 pm I am aware of the Adafruit TCA9548A 1-to-8 I2C Multiplexer, but wanted to avoid using them
There's no way to avoid an I2C multiplexer.

The APDS9960's I2C address is fixed, so you get exactly one per bus. If you want 40 sensors, you need 40 independent I2C buses.

Even with the TCA9548A, you'd need one to manage connections to seven sub-multiplexers, each of which controls access to a set of 8 buses.

Locked
Please be positive and constructive with your questions and comments.

Return to “Microcontrollers”