TCA9548A I2C multiplexer (8 channels) with ESP32

Supply 3.3-5 V Bus I2C I2C address 0x70 / 0x71 / 0x72 / 0x73 / 0x74 / 0x75 / 0x76 / 0x77

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VIN	Power	3V3	3 to 5 V
GND	Ground	GND
SCL	I2C clock (SCL)	D22
SDA	I2C data (SDA)	D21
RST	Not wired to the ESP32	—	Reset, active LOW, pulled up. Leave unconnected
A0	Not wired to the ESP32	—	Address select. All unconnected = 0x70
A1	Not wired to the ESP32	—
A2	Not wired to the ESP32	—
SD0	Not wired to the ESP32	—	Channel SDA: to a sensor, not to the ESP32
SC0	Not wired to the ESP32	—	Channel SCL: to a sensor, not to the ESP32
SD1	Not wired to the ESP32	—
SC1	Not wired to the ESP32	—
SD2	Not wired to the ESP32	—
SC2	Not wired to the ESP32	—
SD3	Not wired to the ESP32	—
SC3	Not wired to the ESP32	—
SD4	Not wired to the ESP32	—
SC4	Not wired to the ESP32	—
SD5	Not wired to the ESP32	—
SC5	Not wired to the ESP32	—
SD6	Not wired to the ESP32	—
SC6	Not wired to the ESP32	—
SD7	Not wired to the ESP32	—
SC7	Not wired to the ESP32	—

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x70);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "TCA9548A I2C multiplexer (8 channels) found at 0x70" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Texas Instruments TCA9548A datasheet, Slave address 1110 A2 A1 A0 (0x70 to 0x77); control register selects channels
Adafruit TCA9548A 1-to-8 I2C multiplexer breakout guide, Pinouts; channel pull-ups must be on the sensor boards

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.

TCA9548A I2C multiplexer (8 channels) with ESP32

Pins and ESP32 wiring

Starter code (Arduino)

Sources

Try it in 3D in BoardPilot

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