Qwiic Mux - PCA9548A

The Qwiic Mux - PCA9548A enables communication with multiple I²C devices that have the same address and between different bus voltages (2.8V, 3.3V, and 5V). The PCA9548A is a very easy to use I²C multiplexer enabling up to 8 buses. This means you can communicate with 8 of the same device or mix and match between 5V, 3.3V and 2.8V devices. The PCA9548A can be daisy chained as well, so, if needed, you can use up to eight of the shields at the same time enabling a whopping 64 buses.

Some I²C devices have a selectable address, but many have only one. The Qwiic Mux allows control of multiple haptic drivers, multiple accelerometers, or finger sensors with ease.

We took all the good things from the Arduino Mux Shield and added a scoop of features on top. The Qwiic Mux includes two regulators so the master can operate and power the board at 5V or 3.3V and a regulated 3.3V and 2.8V will be generated for the appropriate buses. A jumper on the rear of the board controls the main bus voltage. Three power LEDs indicate which power rails are active. All 8 buses now have ample decoupling and are broken out to both Qwiic connectors and 0.1" footprints.

How do I use the Qwiic Mux? Connect your platform of choice (Arduino, Photon, Raspberry Pi, etc) to the Main connector over I²C. Connect your device to either the 2.8V, 3.3V, or 5V bus. As you can see from the photo, Qwiic cables make this easy but you can solder male headers or wires to each port as well.

How do I control the PCA9548A? It’s surprisingly easy. Over I²C, you tell the device which port you want to talk to, for example port 3. After that, whatever I²C traffic happens gets sent to port 3. By switching back and forth between ports, it’s easy to talk to multiple devices that have the same address!

What is the difference between the PCA9548A and TCA9548A? Very little. PCA is made by NXP, TCA is made by TI. PCA can operate from 2.3 to 5.5V, TCA can operate from 1.65 to 5.5V. Everything else is identical.

Issues with this version: SparkX moves fast and we’d rather get something into the wild then let it languish in the lab. The top silkscreen is correct but the rear silkscreen incorrectly identifies ports 0, 1, and 2 as 5V. Ports 0 and 1 are 3.3V, Port 2 is 2.8V.

The Qwiic system enables fast and solderless connection between popular platforms and various sensors and actuators. You can read more about the Qwiic system here. We carry 200mm, 100mm, 50mm, and breadboard friendly Qwiic cables.

We do not plan to regularly produce SparkX products so get them while they’re hot!

Features:

• Works with popular platforms including Arduino, Photon, Raspberry Pi, Tessel 2, ESP32/ESP8266, and Edison
• 9 ports with Qwiic connectors and 0.1" footprints
• Four 3.3V buses, two 2.8V buses, two 5V buses
• On board 3.3V (600mA) and 2.8V (150mA) regulation
• Bus power indicator LEDs
• Pull-up resistors and decoupling caps provided on all buses
• Address jumpers to enable up to eight shields operating at the same time

Documents:

• Schematic
• Eagle Files
• PCA9548A Datasheet, TCA9548A Datasheet
• Arduino example sketches showing how to talk to two MMA8452Q accelerometers simultaneously
• To get the latest files please visit the GitHub repo