How to Use qwiic multiport: Examples, Pinouts, and Specs

The Qwiic Multiport is a compact and efficient connector designed to simplify the process of connecting multiple I2C devices to a single I2C bus. It features multiple Qwiic connectors, enabling seamless communication between various sensors, modules, and microcontrollers. The Qwiic Multiport is part of the Qwiic ecosystem, which uses standardized 4-pin JST connectors for I2C communication, eliminating the need for soldering and reducing wiring complexity.

• Expanding the number of I2C devices connected to a microcontroller.
• Prototyping and testing multiple I2C sensors or modules simultaneously.
• Building modular and scalable systems for IoT, robotics, and automation.
• Simplifying wiring in compact or space-constrained projects.

The Qwiic Multiport is a passive breakout board that splits a single I2C bus into multiple Qwiic connectors. Below are its key technical details:

• Input Voltage: 3.3V or 5V (depends on the connected I2C devices)
• I2C Protocol: Standard I2C (100 kHz) and Fast I2C (400 kHz) supported
• Connectors: 4-pin JST Qwiic connectors (1 input, 3-8 outputs depending on the model)
• Dimensions: Varies by model (e.g., 1.0" x 1.0" for a 4-port version)
• Compatibility: Fully compatible with all Qwiic-enabled devices and microcontrollers.

The Qwiic Multiport uses standardized 4-pin JST connectors for I2C communication. The pinout is as follows:

1. Connect the Multiport to a Microcontroller:
   • Use a Qwiic cable to connect the input port of the Multiport to the I2C port of your microcontroller (e.g., Arduino UNO with a Qwiic shield).
2. Connect I2C Devices:
   • Plug Qwiic-enabled sensors or modules into the output ports of the Multiport using Qwiic cables.
3. Power the System:
   • Ensure the microcontroller and connected devices are powered appropriately (3.3V or 5V as required).
4. Address Conflicts:
   • Verify that all connected I2C devices have unique addresses. If two devices share the same address, use an I2C address changer or modify the device's address (if supported).

• Cable Length: Keep Qwiic cable lengths as short as possible to avoid signal degradation, especially at higher I2C speeds (400 kHz).
• Pull-Up Resistors: The Qwiic Multiport does not include pull-up resistors. Ensure that your microcontroller or one of the connected devices provides the necessary pull-up resistors for the SDA and SCL lines.
• Power Supply: Confirm that the total current draw of all connected devices does not exceed the power supply capacity of your microcontroller or external power source.

Below is an example of connecting two I2C sensors to an Arduino UNO using the Qwiic Multiport.

1. Attach a Qwiic shield to the Arduino UNO.
2. Connect the Qwiic Multiport to the Qwiic shield using a Qwiic cable.
3. Plug two Qwiic-enabled sensors (e.g., a temperature sensor and an accelerometer) into the Multiport.

#include <Wire.h>

// Define I2C addresses for the connected devices
#define TEMP_SENSOR_ADDR 0x48  // Replace with your temperature sensor's address
#define ACCEL_SENSOR_ADDR 0x1D // Replace with your accelerometer's address

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Start serial communication for debugging

  // Check communication with the temperature sensor
  Wire.beginTransmission(TEMP_SENSOR_ADDR);
  if (Wire.endTransmission() == 0) {
    Serial.println("Temperature sensor detected!");
  } else {
    Serial.println("Temperature sensor not found.");
  }

  // Check communication with the accelerometer
  Wire.beginTransmission(ACCEL_SENSOR_ADDR);
  if (Wire.endTransmission() == 0) {
    Serial.println("Accelerometer detected!");
  } else {
    Serial.println("Accelerometer not found.");
  }
}

void loop() {
  // Add your code to read data from the sensors and process it
}

1. Devices Not Detected:

   • Cause: Address conflict or incorrect wiring.
   • Solution: Check the I2C addresses of all connected devices and ensure they are unique. Verify all Qwiic cables are securely connected.

2. No Data from Sensors:

   • Cause: Missing pull-up resistors or incorrect power supply voltage.
   • Solution: Ensure pull-up resistors are present on the SDA and SCL lines. Verify that the power supply voltage matches the requirements of the connected devices.

3. Signal Degradation:

   • Cause: Excessive cable length or too many devices on the bus.
   • Solution: Use shorter Qwiic cables and reduce the number of devices if necessary. Consider using an I2C buffer for long-distance communication.

• Q: Can I connect non-Qwiic I2C devices to the Multiport?
  A: Yes, but you will need to use an adapter or manually wire the device to match the Qwiic pinout.

• Q: How many devices can I connect to the Qwiic Multiport?
  A: The number of devices depends on the number of output ports on your Multiport model. However, the I2C bus can theoretically support up to 127 devices, provided there are no address conflicts and the bus capacitance is within limits.

• Q: Does the Qwiic Multiport support 5V I2C devices?
  A: Yes, as long as your microcontroller and connected devices are compatible with 5V logic levels. Ensure all devices on the bus operate at the same voltage level.

By following this documentation, you can effectively use the Qwiic Multiport to expand your I2C bus and simplify your project wiring.