How to Use Teensy 4.0: Examples, Pinouts, and Specs

The Teensy 4.0, manufactured by PJRC (Part ID: Teensy 4.0), is a high-performance microcontroller board powered by the NXP i.MX RT1062 chip. It features a 600 MHz ARM Cortex-M7 processor, making it one of the fastest microcontroller boards available. With 1 MB of RAM, 2 MB of flash memory, and support for USB host and device functionality, the Teensy 4.0 is well-suited for demanding applications such as robotics, IoT devices, audio processing, and real-time data acquisition.

• Robotics: High-speed control and sensor integration.
• IoT Devices: Low-power, high-performance edge computing.
• Audio Processing: Real-time audio effects and synthesis.
• Data Acquisition: High-speed data logging and processing.
• Custom USB Devices: USB MIDI, HID, or mass storage devices.

The Teensy 4.0 has a total of 40 pins, including digital, analog, and power pins. Below is a summary of the pin configuration:

1. Powering the Board:

   • Connect the Teensy 4.0 to a computer or USB power source using a micro-USB cable.
   • Alternatively, supply 5 V to the VIN pin for external power.

2. Programming the Board:

   • Install the Arduino IDE and the Teensyduino add-on from PJRC's website.
   • Select "Teensy 4.0" as the target board in the Arduino IDE.
   • Write your code and upload it to the board via the USB connection.

3. Connecting Peripherals:

   • Use the GPIO pins for digital and analog I/O.
   • Connect sensors, actuators, or communication modules to the appropriate pins.

4. USB Host Functionality:

   • Use pins 26 and 27 for USB host applications (e.g., connecting a keyboard or mouse).

• Voltage Levels: The Teensy 4.0 operates at 3.3 V logic levels. While some pins are 5 V tolerant, ensure that connected devices are compatible.
• Heat Management: At 600 MHz, the processor may generate heat. Consider adding a heatsink for prolonged high-performance use.
• Bootloader Button: Use the onboard button to manually enter programming mode if needed.
• Static Protection: Handle the board with care to avoid damage from electrostatic discharge (ESD).

The following example demonstrates how to blink the onboard LED (pin 33):

// Blink the onboard LED on Teensy 4.0
// The LED is connected to pin 33 and is active HIGH.

void setup() {
  pinMode(33, OUTPUT); // Set pin 33 as an output
}

void loop() {
  digitalWrite(33, HIGH); // Turn the LED on
  delay(500);             // Wait for 500 milliseconds
  digitalWrite(33, LOW);  // Turn the LED off
  delay(500);             // Wait for 500 milliseconds
}

1. The board is not recognized by the computer:

   • Ensure the USB cable is a data cable (not a charge-only cable).
   • Press the bootloader button to force the board into programming mode.

2. Code does not upload:

   • Verify that "Teensy 4.0" is selected as the target board in the Arduino IDE.
   • Check for loose USB connections or try a different USB port.

3. Peripherals are not working as expected:

   • Double-check the wiring and pin assignments in your code.
   • Ensure that the connected devices are compatible with 3.3 V logic levels.

4. The board overheats:

   • Reduce the clock speed in the Arduino IDE if your application does not require 600 MHz.
   • Add a heatsink for better thermal management.

Q: Can the Teensy 4.0 run at lower clock speeds?
A: Yes, the clock speed can be adjusted in the Arduino IDE to reduce power consumption and heat.

Q: Does the Teensy 4.0 support Ethernet?
A: Yes, the Teensy 4.0 supports Ethernet via an external PHY module.

Q: Can I use the Teensy 4.0 with 5 V sensors?
A: While some pins are 5 V tolerant, it is recommended to use level shifters for 5 V sensors to avoid damage.

Q: How do I reset the Teensy 4.0?
A: Press the onboard bootloader button to reset or reprogram the board.

This concludes the documentation for the Teensy 4.0. For more information, visit the official PJRC website.