Comments on: I2C Multiplexer Shield Testing

By: kwong

kwong — Wed, 17 Apr 2013 23:10:29 +0000

Yes, you will need pull up resistors (typically between 1K to 10K) on each device’s SCL/SDA lines.

By: Reebbhaa Mehta

Reebbhaa Mehta — Wed, 17 Apr 2013 21:30:18 +0000

How did you hook up the TCA9548A to your slave devices? Did you use pull up resistors? I’m having trouble figuring out the values of my pull up resistors.

By: casey g

casey g — Tue, 05 Feb 2013 18:55:43 +0000

Thanks! I just looked up PCA9548A on ti.com and ordered it’s replacement, TCA9548A – http://www.ti.com/product/tca9548a

By: kwong

kwong — Tue, 05 Feb 2013 18:47:21 +0000

Hi Casey,

Yes, using PCA9548A would be perfect for addressing multiple I2C devices with the same address as you would connect only one device at a time.

By: casey g

casey g — Tue, 05 Feb 2013 18:43:50 +0000

Might have mis-read the purpose of the PCA9517… Sounds like I do need the PCA9548A to do this?

By: casey g

casey g — Tue, 05 Feb 2013 18:21:43 +0000

Kerry – I’m working on a project where I need something like this to control 4 ADXL345′s from a single arduino, but I’m a noob when it comes to the electronics side of things. I can get my hand on ADXL345 breakout boards that use 2 different I2C addresses, but was struggling with how I would connect 4 when I only have 2 unique addresses.

Was curious if you would recommend using the PCA9548A chip (from this write up) or the PCA9517 chip (from http://www.kerrywong.com/2011/05/08/a-dual-temperature-display-with-humidity-measurement/) to solve this?

And either way, where do you get these chips?

Cheers.

Casey.

By: kwong

kwong — Tue, 09 Oct 2012 12:02:28 +0000

Thanks Vladimir. I just fixed the link.

By: Vladimir

Vladimir — Tue, 09 Oct 2012 07:37:41 +0000

Hello. Great explaining of I2C multiplexer function, thank you.
BTW, you have an error in the link to PCA9548A datasheet (need to add ‘http://’ at the beginning).