Update: Keyboard & Mouse type are now available in Teensyduino 0.6. Select it from the Tools->Boards menu, and your sketch can type with Keyboard.print("whatever") and use the mouse with Mouse.move(x,y) and Mouse.click().

Running Sketches on the Teensy

Many type of sketches are able to run on the Teensy! The digitial I/O pins work with digitialWrite(pin,value), digitalRead(pin), and pinMode(pin,mode). The PWM pins can be used with analogWrite(pin,value). Eight (8) pins can be used as interrupts with attachInterrupt(). The Teensy++ has 8 analog inputs that can be used with analogRead().

Communication can be done using Serial.print() and other communication functions normally used for communication on the Arduino board. Unlike the Arduino, which converts 38.4 kbps serial to USB, the Teensy has direct 12 MBit/sec USB access, so communications are sent and received at full USB speed.

Direct USB access is possible, so the Teensy is not limited to being only a serial-type USB device. Your sketch can use a Keyboard/Mouse board setting, which make become a USB keyboard and mouse! Future Teensyduino releases will add more USB device types.

The Teensy also has a serial port. It is not connected the USB port and can be used separately.

How Does Teensy Compare With The Arduino Board?

Specification	Teensy	Teensy++	Arduino
Processor	ATMEGA32U4	AT90USB646	ATMEGA328
Flash Memory	32256	130048	30720
RAM Memory	2560	8192	2048
EEPROM Memory	1024	4096	1024
Total I/O	25	46	20
Analog Inputs	12	8	6
PWM (Analog Out)	7	9	6
USB Port	1	1	(serial only)

Teensy uses a similar Atmel AVR processor as the Arduino board, but there are differences. The most important is direct, built-in USB on the Teensy compared to serial converted to USB by a separate chip on the Arduino. Teensy communications MUCH faster than Arduino. Starting with Teensyduino 0.6, Teensy can communicate as a USB keyboard and mouse, which is impossible with an Arduino board that has a fixed USB to serial converter chip.

Teensy is designed for easy use on breadboards in the smallest possible size, which is incompatible with the form-factor used by Arduino shields.

While many types of sketches can run, Teensy is NOT an "Arduino clone" due to the substantial technical differences. The Teensy hardware and Teensyduino software add-on are NOT endorsed or supported by the Arduino developer team.