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I2C Switch

I2C Switch expansion board for the Raspberry Pi
Top View
Top View
As Supplied
On a Raspberry Pi Zero
On a Raspberry Pi 4

£7.99 each (including VAT: £9.59)

199 in stock to order today.

Features

  • 4 I2C channels
  • Channel selection via I2C-bus, in any combination
  • 3 address pins allowing up to 8 devices on the I2C-bus
  • Allows voltage level translation between 2.7 V, 3.3 V and 5 V buses
  • 0 Hz to 400 kHz clock frequency

The I2C Switch from AB Electronics UK is a 4 channel bidirectional I2C switch controlled via the I2C-bus.  It is designed for use on all Raspberry Pi models with the 40 pin GPIO connector. The I2C Switch can be securely fitted to your Raspberry Pi using our mounting kit pack.

The I2C Switch is based around a PCA9546A controller from NXP.  The PCA9546A provides quad bi-directional communication between the I2C port on the Raspberry Pi and any attached I2C devices.  Each channel can be individually enabled or disabled allowing you to connect I2C devices that share the same address to your Raspberry Pi.

Powered through the host Raspberry Pi using the GPIO port and extended pins on the GPIO connector allowing you to stack the I2C Switch along with other expansion boards.

Each channel can operate at 2.7V, 3.3V or 5V allowing you to mix different voltage I2C devices on your Raspberry Pi. 

Pull-up resistors need to be fitted to the SDA and SCL pins on each channel.  We recommend using a value of between 2.2K and 10K for the pull-up resistors.

The pinout for each channel matches the first 6 pins on the Raspberry Pi GPIO connector with 3.3V, 5V, Ground, SDA and SCL.

The I2C switch supports clock frequencies up to 400KHz.

The reset pin on the PCA9546A is connected to GPIO 27 (pin 13) on the Raspberry Pi GPIO header allowing you to recover from a situation in which one of the downstream I2C buses is stuck in a low state.


Specifications

Input Ratings & Specifications

Spec
Ratings
Host I2C SDA/SCL voltage
3.3 V
Channel I2C SDA/SCL voltage
2.7 V - 5V
I2C port current
25 mA
Max Clock Frequency
400KHz

Schematic

Click to download
Click to download schematic PDF.

Mechanical Drawings

Mechanical Drawing


Assembly

The I2C Switch is supplied with the 40 pin GPIO connector unsoldered. 

Before using the I2C Switch you will need to solder the 40 pin GPIO connector.

PCB Header Assembly Jig

Download and print our PCB Header Assembly Jig to hold your circuit board when soldering the header pins.

Use
 

I2C Address Table

The I2C Switch includes three address selection solder jumpers which can be bridged with solder to give you up to 8 different I2C addresses.

2 1 0 Address
      0x70
    0x71
    0x72
  0x73
    0x74
  0x75
  0x76
0x77

Compatibility

Model Status
Raspberry Pi Model A No
Raspberry Pi Model B No
Raspberry Pi 1 Model A+ Yes
Raspberry Pi 1 Model B+ Yes
Raspberry Pi 2 Model B Yes
Raspberry Pi 3 Model B Yes
Raspberry Pi 4 Yes
Raspberry Pi Zero Yes
Raspberry Pi Zero W Yes
Orange Pi Yes
Asus Tinker Board Yes
Odroid Yes

Code Libraries and Demos

We have Python, C and C++ and Node JS libraries available for this expansion board.  You can download all of the libraries from github at:

https://github.com/abelectronicsuk/ or click on the logos below for your selected programming language,


Datasheets

PCA9546A (I2C Switch)


Related Items

Important Information

This development board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by abelectronics.co.uk to be a finished end-product fit for general consumer use. As such, the goods being provided are not intended to be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety and environmental measures typically found in end products that incorporate such semiconductor components or circuit boards. Persons handling the product(s) must have electronics training and observe good engineering practice standards. This development board/kit does not fall within the scope of the European Union directives regarding electromagnetic compatibility, restricted substances (RoHS), recycling (WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of these directives or other related directives. Note: documents in Portable Document Format (PDF) require Adobe Acrobat Reader 5.0 or higher to view, download Adobe Acrobat Reader or other PDF reading software for your computer or mobile device.