Sparkfun Teensy 3.5 4.0 Development Board

*Teensy 3.5 Development Board
The Teensy is a breadboard-friendly development board with loads of features in a, well, teensy package. Each Teensy 3.5 comes pre-flashed with a bootloader so you can program it using the on-board USB connection: no external programmer needed! You can program for the Teensy in your favorite program editor using C *or *you can install the Teensyduino add-on for the Arduino IDE and write Arduino sketches for it!

Features:
120MHz ARM Cortex-M4 with Floating Point Unit
512K Flash, 256K RAM, 4K EEPROM
Microcontroller Chip MK64FX512VMD12
1 CAN Bus Port
16 General Purpose DMA Channels
5V Tolerance on All Digital I/O Pins
62 I/O Pins (42 breadboard friendly)
25 Analog Inputs to 2 ADCs with 13-bit resolution
2 Analog Outputs (DACs) with 12-bit resolution
20 PWM Outputs (Teensy 3.6 has 22 PWM)
USB Full Speed (12Mbit/sec) Port
Ethernet mac, capable of full 100Mbit/sec speed
Native (4-bit SDIO) micro SD card port
I2S Audio Port, 4-Channel Digital Audio Input & Output
14 Hardware Timers
Cryptographic Acceleration Unit
Random Number Generator
CRC Computation Unit
6 Serial Ports (2 with FIFO and Fast Baud Rates)
3 SPI Ports (1 with FIFO)
3 I2C Ports
Real-Time Clock
62.3mm x 18.0mm x 4.2mm (2.5in x 0.7in x 0.2in)

Note: This does not come with a USB cable; please check below for an appropriate one.

*Sparkfun Teensy 4.0
Teensy 4.0 features an ARM Cortex-M7 processor at 600MHz, with a NXP iMXRT1062 chip, the fastest microcontroller available today. Teensy 4.0 is the same size and shape as Teensy 3.2, and retains compatibility with most of the pin functions on Teensy 3.2.

Features:
ARM Cortex-M7 at 600MHz
1024K RAM (512K is tightly coupled)
2048K Flash (64K reserved for recovery & EEPROM emulation)
2 USB ports, both 480MBit/sec
3 CAN Bus (1 with CAN FD)
2 I2S Digital Audio
1 S/PDIF Digital Audio
1 SDIO (4 bit) native SD
3 SPI, all with 16 word FIFO
3 I2C, all with 4 byte FIFO
7 Serial, all with 4 byte FIFO
32 general purpose DMA channels
31 PWM pins
40 digital pins, all interrrupt capable
14 analog pins, 2 ADCs on chip
Cryptographic Acceleration
Random Number Generator
RTC for date/time
Programmable FlexIO
Pixel Processing Pipeline
Peripheral cross triggering
Power On/Off management

Teensy 4.0's Cortex-M7 processor includes a floating point unit (FPU) which supports both 64 bit "double" and 32 bit "float". With M4's FPU on Teensy 3.5 & 3.6, and also Atmel SAMD51 chips, only 32 bit float is hardware accelerated. Any use of double, double functions like log(), sin(), cos() means slow software implemented math. Teensy 4.0 executes all of these with FPU hardware.

Note: Please be aware that the Teensy 4.0 does not include headers and will need to be purchased separately and soldered on yourself.