Datasheet

ManualsBrandsArduino ManualsArduino ControllersArduino Leonardo

The Arduino Leonardo is a

microcontroller board based on the

ATmega32u4 (datasheet). It has 20

digital input/output pins (of which 7

can be used as PWM outputs and 12

as analog inputs), a 16 MHz crystal

oscillator, a micro USB connection, a

power jack, an ICSP header, and a

reset button. It contains everything

needed to support the

microcontroller; simply connect it to

a computer with a USB cable or

power it with a AC-to-DC adapter or

battery to get started.

The Leonardo differs from all

preceding boards in that the

ATmega32u4 has built-in USB

communication, eliminating the need for a secondary processor. This allows the Leonardo to

appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC)

serial / COM port. It also has other implications for the behavior of the board; these are

detailed on the getting started page.

Microcontroller

ATmega32u4

Operating Voltage

Input Voltage (recommended)

7-12V

Input Voltage (limits)

6-20V

Digital I/O Pins

PWM Channels

Analog Input Channels

DC Current per I/O Pin

40 mA

DC Current for 3.3V Pin

50 mA

Flash Memory

32 KB (ATmega32u4) of which 4 KB used by bootloader

SRAM

2.5 KB (ATmega32u4)

EEPROM

1 KB (ATmega32u4)

Clock Speed

16 MHz

EAGLE files: arduino-leonardo-reference-design.zip

Schematic: arduino-leonardo-schematic-rev3b.pdf

The Arduino Leonardo can be powered via the micro USB connection or with an external

power supply. The power source is selected automatically.

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery.

The adapter can be connected by plugging a 2.1mm center-positive plug into the board's

power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the

POWER connector.

The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V,

however, the 5V pin may supply less than five volts and the board may be unstable. If using

Summary of content (4 pages)

PAGE 1
The Arduino Leonardo is a microcontroller board based on the ATmega32u4 (datasheet). It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.
PAGE 2
more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts. The power pins are as follows: VIN. The input voltage to the Arduino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin. 5V.
PAGE 3
Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board. See also the mapping between Arduino pins and ATmega32u4 ports. The Leonardo has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The ATmega32U4 provides UART TTL (5V) serial communication, which is available on digital pins 0 (RX) and 1 (TX).
PAGE 4
The maximum length and width of the Leonardo PCB are 2.7 and 2.1 inches respectively, with the USB connector and power jack extending beyond the former dimension. Four screw holes allow the board to be attached to a surface or case. Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.