Teensy 4.1 with Ethernet 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. This version has the pin headers pre-assembled - great for those who don't enjoy soldering. We also stock the standard unassembled with Ethernet version which comes with free separate pin header strips. 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. Feature Teensy 4.1 Teensy 4.0 Ethernet 10 / 100 Mbit DP83825 PHY (6 pins) -none- 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 Pinouts Teensy 4.1 is designed to bring all general-purpose I/O pins to breadboard-friendly pads on the outside edges. Ethernet To use the Ethernet port, a magjack and capacitor need to be connected. We have the PJRC Ethernet kit available here. 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. https://elecena.pl/product/28093224/teensy-4-1-with-ethernet-headers 2025-03-28 https://elecena.pl/product/28093224/teensy-4-1-with-ethernet-headers 2025-04-10 https://elecena.pl/product/28093224/teensy-4-1-with-ethernet-headers 2025-08-05 https://elecena.pl/product/28093224/teensy-4-1-with-ethernet-headers 2025-11-28 https://elecena.pl/product/28093224/teensy-4-1-with-ethernet-headers 2025-11-29