The TCA954X/PCA954X group of devices is a set of I2C switches. Several types are available, with 2, 4 or 8 channels, and different voltage specifications. The first letter is sometimes also "P". Not to be confused with PCA95x4, which is a set of GPIO expanders.
The TCA9548A device has eight bidirectional translating switches that can be controlled through the I2C bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels.
All operations for basic usage has been developed. If needed, RESET operation can also be implemented.
TCA9548A datasheet
You will find this device as "Adafruit TCA9548A 1-to-8 I2C Multiplexer Breakout"
A list of different variants is available on the Texas Instruments Website.
Create a Tca9548A class and pass the I2C device. The default I2C address is provided in the class.
Console.WriteLine("Hello TCA9548A!");
var bus = I2cBus.Create(1);
Tca9548A tca9548a = new Tca9548A(bus.CreateDevice(Tca9548A.DefaultI2cAddress), bus);
// Get all connected I2C interfaces
foreach (var channelBuses in tca9548a)
{
var deviceAddress = ((Tca9548AChannelBus)channelBuses).PerformBusScan();
foreach (var device in deviceAddress)
{
if (device == Bno055Sensor.DefaultI2cAddress || device == Bno055Sensor.SecondI2cAddress)
{
Bno055Sensor bno055Sensor = new Bno055Sensor(channelBuses.CreateDevice(device));
Console.WriteLine($"Id: {bno055Sensor.Info.ChipId}, AccId: {bno055Sensor.Info.AcceleratorId}, GyroId: {bno055Sensor.Info.GyroscopeId}, MagId: {bno055Sensor.Info.MagnetometerId}");
Console.WriteLine($"Firmware version: {bno055Sensor.Info.FirmwareVersion}, Bootloader: {bno055Sensor.Info.BootloaderVersion}");
Console.WriteLine($"Temperature source: {bno055Sensor.TemperatureSource}, Operation mode: {bno055Sensor.OperationMode}, Units: {bno055Sensor.Units}");
Console.WriteLine($"Powermode: {bno055Sensor.PowerMode}");
var calibrationStatus = bno055Sensor.GetCalibrationStatus();
Console.WriteLine($"Calibration Status : {calibrationStatus}");
var magneto = bno055Sensor.Magnetometer;
Console.WriteLine($"Magnetometer X: {magneto.X} Y: {magneto.Y} Z: {magneto.Z}");
var gyro = bno055Sensor.Gyroscope;
Console.WriteLine($"Gyroscope X: {gyro.X} Y: {gyro.Y} Z: {gyro.Z}");
var accele = bno055Sensor.Accelerometer;
Console.WriteLine($"Acceleration X: {accele.X} Y: {accele.Y} Z: {accele.Z}");
var orien = bno055Sensor.Orientation;
Console.WriteLine($"Orientation Heading: {orien.X} Roll: {orien.Y} Pitch: {orien.Z}");
var line = bno055Sensor.LinearAcceleration;
Console.WriteLine($"Linear acceleration X: {line.X} Y: {line.Y} Z: {line.Z}");
var gravity = bno055Sensor.Gravity;
Console.WriteLine($"Gravity X: {gravity.X} Y: {gravity.Y} Z: {gravity.Z}");
var qua = bno055Sensor.Quaternion;
Console.WriteLine($"Quaternion X: {qua.X} Y: {qua.Y} Z: {qua.Z} W: {qua.W}");
var temp = bno055Sensor.Temperature.DegreesCelsius;
Console.WriteLine($"Temperature: {temp} °C");
}
else if (device == Bmp180.DefaultI2cAddress)
{
using Bmp180 i2cBmp280 = new(channelBuses.CreateDevice(device));
// set samplings
i2cBmp280.SetSampling(Sampling.Standard);
// read values
Temperature tempValue = i2cBmp280.ReadTemperature();
Console.WriteLine($"Temperature: {tempValue.DegreesCelsius:0.#}\u00B0C");
Pressure preValue = i2cBmp280.ReadPressure();
Console.WriteLine($"Pressure: {preValue.Hectopascals:0.##}hPa");
// Note that if you already have the pressure value and the temperature, you could also calculate altitude by
// calling WeatherHelper.CalculateAltitude(preValue, Pressure.MeanSeaLevel, tempValue) which would be more performant.
Length altValue = i2cBmp280.ReadAltitude(WeatherHelper.MeanSeaLevel);
Console.WriteLine($"Altitude: {altValue:0.##}m");
Thread.Sleep(1000);
// set higher sampling
i2cBmp280.SetSampling(Sampling.UltraLowPower);
// read values
tempValue = i2cBmp280.ReadTemperature();
Console.WriteLine($"Temperature: {tempValue.DegreesCelsius:0.#}\u00B0C");
preValue = i2cBmp280.ReadPressure();
Console.WriteLine($"Pressure: {preValue.Hectopascals:0.##}hPa");
// Note that if you already have the pressure value and the temperature, you could also calculate altitude by
// calling WeatherHelper.CalculateAltitude(preValue, Pressure.MeanSeaLevel, tempValue) which would be more performant.
altValue = i2cBmp280.ReadAltitude(WeatherHelper.MeanSeaLevel);
Console.WriteLine($"Altitude: {altValue:0.##}m");
}
Thread.Sleep(1000);
}
}Important to understand: If you are getting lower data rate from sensor connected via Multiplexer on Raspberry Pi, you need to adjust the bus speed.
This example uses the I2C bus 1 with GPIO 2 and 3 on raspberry pi and gathers data from to BNO055 sensors and 4 BMP180 sensors over TCA9548A Mux
TCA9546A datasheet You can use the same class to control the 4-Channel Multiplexer also.