How to Use Teensy 4.1+: Examples, Pinouts, and Specs

The Teensy 4.1+ is a high-performance microcontroller board powered by a 600 MHz ARM Cortex-M7 processor. It is designed for demanding applications requiring significant processing power, such as audio processing, real-time data acquisition, robotics, and advanced IoT systems. The Teensy 4.1+ offers extensive connectivity options, including Ethernet, USB host, and multiple serial interfaces, making it a versatile choice for developers. It is fully compatible with the Arduino IDE, allowing for easy programming and integration into existing projects.

• Audio synthesis and digital signal processing (DSP)
• Robotics and motor control
• High-speed data acquisition and logging
• IoT devices with Ethernet or USB connectivity
• Advanced sensor fusion and machine learning applications
• Real-time control systems

The Teensy 4.1+ features a total of 55 digital I/O pins, with multiple functions assigned to each pin. Below is a summary of the pin configuration:

For a complete pinout diagram, refer to the official Teensy 4.1+ documentation.

1. Powering the Board:

   • The Teensy 4.1+ can be powered via the USB port (5V) or an external power supply (3.6V to 5.5V). Ensure the power source is stable and within the specified range.

2. Connecting Peripherals:

   • Use the digital and analog pins to connect sensors, actuators, and other peripherals. For communication, utilize the UART, SPI, I2C, or CAN interfaces as needed.

3. Programming the Board:

   • Install the Arduino IDE and the Teensyduino add-on. Select "Teensy 4.1" as the board type in the IDE. Write your code and upload it via the USB connection.

4. Using the SD Card Slot:

   • Insert a microSD card into the onboard slot for data logging or file storage. Use the SD library in Arduino to interact with the card.

• Voltage Levels: The Teensy 4.1+ operates at 3.3V logic levels. Ensure all connected devices are compatible or use level shifters.
• Heat Management: For intensive applications, consider adding a heatsink to the processor to prevent overheating.
• Pin Protection: Avoid applying voltages higher than 3.3V to the I/O pins to prevent damage.
• Ethernet Usage: To use the Ethernet interface, connect an external Ethernet PHY module to the dedicated pins.

Below is an example of how to blink an LED connected to pin 13:

// This example blinks an LED connected to pin 13 on the Teensy 4.1+.
// The LED will turn on for 1 second and off for 1 second in a loop.

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

Here is an example of reading an analog sensor connected to pin A0:

// This example reads the value of an analog sensor connected to pin A0
// and prints the value to the Serial Monitor.

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
}

void loop() {
  int sensorValue = analogRead(A0); // Read the analog value from pin A0
  Serial.println(sensorValue);      // Print the value to the Serial Monitor
  delay(500);                       // Wait for 500 milliseconds
}

1. The board is not recognized by the computer:

   • Ensure the USB cable is data-capable (not charge-only).
   • Check that the Teensyduino add-on is installed in the Arduino IDE.
   • Press the reset button on the Teensy 4.1+ to force it into programming mode.

2. Code does not upload:

   • Verify that "Teensy 4.1" is selected as the board type in the Arduino IDE.
   • Ensure no other program is using the COM port assigned to the Teensy.

3. Peripherals are not working as expected:

   • Double-check the wiring and connections.
   • Confirm that the peripherals are compatible with 3.3V logic levels.
   • Use a multimeter to verify power and signal integrity.

4. Ethernet is not functioning:

   • Ensure the Ethernet PHY module is correctly connected to the dedicated pins.
   • Use the Ethernet library in Arduino and verify the configuration.

• Can I use 5V sensors with the Teensy 4.1+?
  Yes, but you will need level shifters to convert the 5V signals to 3.3V.

• What is the maximum SD card size supported?
  The Teensy 4.1+ supports SD cards up to 128 GB, formatted as FAT32 or exFAT.

• Can I use the Teensy 4.1+ without the Arduino IDE?
  Yes, you can use other development environments like PlatformIO or write bare-metal code.

• Does the Teensy 4.1+ support Wi-Fi?
  No, but you can add Wi-Fi functionality using external modules like the ESP8266 or ESP32.

This concludes the documentation for the Teensy 4.1+. For further details, refer to the official Teensy website and community forums.