Teensy 4.1 – No Ethernet

This is a new version of the popular Teensy 4.1 but without the Ethernet chip onboard. Why? Because those pesky chip shortages are proving a real headache for the nice folks at PJRC! As many Teensy users don’t need or want the Ethernet features, this was a nice solution to continue providing the much-loved Teensy 4.1 to makers across the planet.

Everything else is the same as the standard Teensy 4.1 with Ethernet, as you’ll see below.

The Teensy 4.1 features the fastest microcontroller and an expanded set of powerful peripherals in a 2.4’x0.7′ form factor and can be programmed using the Arduino IDE with Teensyduino add-on.

Comparison 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.

Pinouts

Teensy 4.1 is designed to bring all general-purpose I/O pins to breadboard-friendly pads on the outside edges. Teensy 4.1 has a total of 55 input/output signal pins. 42 are easily accessible when used with a solderless breadboard. This pinout reference card comes with Teensy 4.1 (front / back).

A larger, more detailed pinout chart by KurtE is also available on the forum.

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.

The PSRAM chip is meant to be soldered to the smaller pads on the bottom side of Teensy 4.1, underneath the SD card socket, between pins 31-32 and 33-34. Do not use the larger pads. A single PSRAM chip must be soldered to the smaller pads to be detected.

USB Host

Teensy 4.1’s USB Host port allows 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.

Specifications

• ARM Cortex-M7 at 600 MHz
• Float point math unit, 64 & 32 bits
• 7936K Flash, 1024K RAM (512K tightly coupled), 4K EEPROM (emulated)
• QSPI memory expansion, locations for 2 extra RAM or Flash chips
• USB device 480 Mbit/sec & USB host 480 Mbit/sec
• 55 digital input/output pins, 35 PWM output pins
• 18 analog input pins
• 8 serial, 3 SPI, 3 I2C ports
• 2 I2S/TDM and 1 S/PDIF digital audio port
• 3 CAN Bus (1 with CAN FD)
• 1 SDIO (4 bit) native SD Card port
• 32 general purpose DMA channels
• Cryptographic Acceleration & Random Number Generator
• RTC for date/time
• Programmable FlexIO
• Pixel Processing Pipeline
• Peripheral cross triggering
• Power On/Off management

Processor

• Performance – ARM Cortex-M7 brings many powerful CPU features to a true real-time microcontroller platform. CPU performance is many times faster than typical 32 bit microcontrollers.
• Dual Issue Superscaler Architecture – Cortex-M7 is a dual-issue superscaler processor, meaning M7 can execute 2 instructions per clock cycle, at 600 MHz! Of course, executing 2 simultaneously depends upon the compiler ordering instructions and registers. Initial benchmarks have shown C++ code compiled by Arduino tends to achieve 2 instructions about 40% to 50% of the time while performing numerically intensive work using integers and pointers.
• Floating Point Unit – The FPU performs 32 bit float and 64 bit double precision math in hardware. 32 bit float speed is approximately the same speed as integer math. 64 bit double precision runs at half the speed of 32 bit float.
• Tightly Coupled Memory – Tightly Coupled Memory is a special feature which allows Cortex-M7 fast single cycle access to memory using a pair of 64 bit wide buses. The ITCM bus provides a 64 bit path to fetch instructions. The DTCM bus is actually a pair of 32 bit paths, allowing M7 to perform up to 2 separate memory accesses in the same cycle. These extremely high speed buses are separate from M7’s main AXI bus, which accesses other memory and peripherals.
• Cache – Two 32K caches, one for instructions and one for data, are used to speed up repetitive access to non-TCM memory.
• Branch Prediction – Cortex-M7 is the first ARM microcontroller to use branch prediction. On Cortex-M4 & earlier, loops and other code which much branch take 3 clock cycles. With M7, after a loop has executed a few times, the branch prediction removes that overhead, allowing the branch instruction to run in only a single clock cycle.
• Digital Signal Processing – DSP extension instructions accelerate signal processing, filters and Fourier transform. The Audio library automatically makes uses of these DSP instructions.

Resources

• Arduino IDE + Teensyduino – Arduino’s IDE software with the Teensyduino add-on is the primary programming environment for Teensy. On Windows, Linux and old Macs, Arduino is installed first and then the Teensyduino installer adds Teensy support to the Arduino IDE. On newer Macs, an all-in-one download is provided. Teensyduino includes a large collection of libraries which are tested and optimized for Teensy. Other libraries may be installed manually or by Arduino’s library manager.
• Visual Micro – Visual Micro allows use of Microsoft Visual Studio to program Arduino compatible boards, including Teensy. Only Windows is supported. Visual Micro is commercial paid software.
• PlatformIO – PlatformIO IDE is a cross platform development environment with many advanced features. Windows, Linux and Macintosh are supported.
• CircuitPython – CircuitPython provides a .HEX file which you program onto Teensy 4.1 using Teensy Loader. Then Teensy appears to your computer as a USB disk, where copy or save your Python code. CircuitPython does not fully support all of Teensy 4.1’s hardware.
• Command Line with Makefile – Makefiles for non-graphical use are provided with the Teensyduino installer.
  • Teensy 4.x: {Arduino}/hardware/teensy/avr/cores/teensy4/Makefile
  • Teensy LC & 3.x: {Arduino}/hardware/teensy/avr/cores/teensy3/Makefile

Revision History

As of 03/04/2024 we are no longer including header strips with our Teensy boards.