Teensy 4.1 Development Board


Teensy 4.1 features the fastest microcontroller and an expanded set of powerful peripherals in a 2.4 by 0.7 inch form factor.

Teensy 4.0 can be programmed using the Arduino IDE with Teensyduino add-on.

Technical Specifications Compared to Teensy 4.0

Teensy 4.1 & 4.0 use the same IMXRT1062, so most technical specifications are the same.

Please refer to the Teensy 4.0 page for common specifications and features.

Feature Teensy 4.1 Teensy 4.0
Ethernet 10 / 100 Mbit
DP83825 PHY
(6 pins)
USB Host 5 Pins with
power management
2 SMT Pads
SDIO (4 bit data) Micro SD Socket 8 SMT Pads
PWM Pins 35 31
Analog Inputs 18 14
Serial Ports 8 7
Flash Memory 8 Mbyte 2 Mbyte
QSPI Memory 2 chips
Plus Program Memory
Program memory only
Breadboard Friendly I/O 42 24
Bottom SMT Pad Signals 7 16
SD Card Signals 6 0
Total I/O Pins 55 40


Teensy 4.1 is designed to bring all general purpose I/O pins to breadboard friendly pads on the outside edges


To use the Ethernet port, a magjack and capacitor need to be connected.

This is currently available only as a DIY project using this OSH Park Shared Circuit Board.

Memory Expansion

The bottom side of Teensy 4.1 has locations to solder 2 memory chips. 

The smaller location is meant for a PSRAM chip. The larger location is intended for flash memory.

USB Host

Teensy 4.1's USB Host port allow you to connect USB devices, like keyboards and MIDI musical instruments. A 5 pin header and a USB Host cable are needed to be able to plug in a USB device.

USB hubs may be used if more than 1 device is needed. See the USBHost_t36 examples for details.