Data Sheet

The power pins are as follows:
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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. The regulated power supply used to power the microcontroller and other
components on the board. This can come either from VIN via an on-board regulator,
or be supplied by USB or another regulated 5V supply.
●
3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is
50 mA.
●
GND. Ground pins.
Memory
The ATmega2560 has 256 KB of flash memory for storing code (of which 8 KB is used for
the bootloader), 8 KB of SRAM and 4 KB of EEPROM (which can be read and written with the
EEPROM library).
Input and Output
Each of the 54 digital pins on the Mega can be used as an input or output, using pinMode()
, digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or
receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default)
of 20-50 kOhms. In addition, some pins have specialized functions:
●
Serial: 0 (RX) and 1 (TX); Serial 1: 19 (RX) and 18 (TX); Serial 2: 17 (RX)
and 16 (TX); Serial 3: 15 (RX) and 14 (TX). Used to receive (RX) and transmit
(TX) TTL serial data. Pins 0 and 1 are also connected to the corresponding pins of the
ATmega8U2 USB-to-TTL Serial chip.
●
External Interrupts: 2 (interrupt 0), 3 (interrupt 1), 18 (interrupt 5),
19 (interrupt 4), 20 (interrupt 3), and 21 (interrupt 2). These pins can be
configured to trigger an interrupt on a low value, a rising or falling edge, or a change
in value. See the attachInterrupt() function for details.
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PWM: 0 to 13. Provide 8-bit PWM output with the analogWrite() function.
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SPI: 50 (MISO), 51 (MOSI), 52 (SCK), 53 (SS). These pins support SPI
communication using the SPI library. The SPI pins are also broken out on the ICSP
header, which is physically compatible with the Uno, Duemilanove and Diecimila.
●
LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH