Multiplexer module, I2C, 8 channels, PCA9548, 3.3-5V

Multiplexer module, compatible with Arduino and other development boards, allows connection of up to 8 devices on the same I2C address. This happens when you have multiple sensors using the same I2C address, making it impossible to use them simultaneously.

The multiplexer itself is at I2C address 0x70 (configurable between 0x70 and 0x77) and works by sending a single byte to the multiplexer specifying the desired channel. The multiplexer communicates with the microcontroller via I2C, and the microcontroller selects which port on the multiplexer will be used. Theoretically, up to 8 multiplexer modules can be used, each with its own address between 0x70 and 0x77, each connected to 8 sensors, for a total of 64 I2C sensors on the same microcontroller.

This module is compatible with 3.3V and 5V logic levels, without the need for a logic level translator.

Specifications:

Supply voltage: 2.3 - 5VDC

Frequency: 0-400kHz

I2C address: Selectable, between 0x70 and 0x77

Number of available channels: 8 buses

Usage:

The address used is set by configuring pins A0, A1, and A2 as follows:

Setting to LOW is done by connecting the respective pin to GND, setting to HIGH by connecting to the module's supply voltage (VCC).

To select an I2C bus for writing/reading, it is necessary to send a byte to the multiplexer with the desired output port (in numeric format, from 0 to 7).

Example of port selection with Arduino:

void TCA9548A(uint8_t bus){

  Wire.beginTransmission(0x70);  // The TCA9548A address is 0x70

  Wire.write(1 << bus);          // send byte to selected bus

  Wire.endTransmission();

  Serial.print(bus);

}

Afterwards, it is sufficient to call the function and send as an argument the port number you want to control before sending I2C commands. For example, to control the device connected to bus number 3, call the following line before other I2C commands. Ports start at 0.

TCA9548A(2);

Pinout: