TCA9548A-RK (community library)

Summary

Particle driver TCA9548A I2C bus multiplexer

Example Build Testing

Library Read Me

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TCA9548A-RK

Particle driver for TCA9548A I2C multiplexer

This handy chip allows 8 separate I2C busses to be connected to a single I2C port. This is handy it you want to connect devices that have conflict I2C addresses. Or if you want to support multiple busses at different voltage levels.

I purchased mine from Adafruit which has the surface mount chip soldered on a handy breakout board.

Pinouts

Bottom side:

• 1 - A0
• 2 - A1
• 3 - /RESET
• 4 SD0
• 5 SC0
• 6 SD1
• 7 SC1
• 8 SD2
• 9 SC2
• 10 SD3
• 11 SC3
• 12 GND

Top side:

• 13 SD4
• 14 SC4
• 15 SD5
• 16 SC5
• 17 SD6
• 18 SC6
• 19 SD7
• 20 SC7
• 21 A2
• 22 SCL
• 23 SDA
• 24 VCC

Note that the Adafruit breakout board has built-in pull-up resistors on the SDL and SCL (to Photon/Electron) lines. These can be disabled by cutting two traces on the bottom side of the board.

Also the A0, A1, and A2 lines have internal pull-downs, so the default address is 0 with no connections. There are solder pads on the bottom to change the address permanently.

Finally, the /RESET line has a pull-up on it, so you don't have to connect it unless you want to be able to hardware reset the chip.

If you are using a bare TCA9548A chip you'll need to add your own ties to GND or VCC, and add pull-ups for I2C.

Also note that neither includes pull-ups on the expanded SDAn and SCLn ports! This is intentional so you can pull-up to either 3.3V or 5V depending on what voltage you want to run the bus at. Each port can be run at a different voltage as desired.

Test Circuit

Examples

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