We sure love the ATmega328 here at Adafruit, and we use them a lot for
our own projects. The processor has plenty of GPIO, Analog inputs,
hardware UART SPI and I2C, timers and PWM galore - just enough for
most simple projects. When we need to go small, we use a Pro Trinket
3V or 5V, but when size isn't as much of a concern, and an USB-serial
converter is required, we reach for an Adafruit METRO.
This is the Adafruit METRO with headers. It comes with headers
soldered on. It's a fully assembled and tested board with SMT headers
attached as well as through hole headers. If you don't want a Metro
with through-hole headers or at least, holes for them, but not
attached for super-slimness, check out our Metro without Headers.
METRO is the culmination of years of playing with AVRs: we wanted to
make a development board that is easy to use and is hacker friendly.
At the heart is an ATmega328P, with 32KB of flash and 2KB of RAM,
running at 16 MHz
* Power the METRO with 7-9V polarity protected DC or the micro USB
connector to any 5V USB source. The 2.1mm DC jack has an on/off switch
next to it so you can turn off your setup easily. The METRO will
automagically switch between USB and DC.
* METRO has 19 GPIO pins, 6 of which are Analog in as well, and 2 of
which are reserved for the USB-serial converter. There's also 6 PWMs
available on 3 timers (1 x 16-bit, 2 x 8-bit). There's a hardware SPI
port, hardware I2C port and hardware UART to USB. Logic level is 5V
but by cutting and soldering closed a jumper, you can easily convert
it to 3.3V logic
* USB to Serial converter, there's a hardware USB to Serial
converter that can be used by any computer to listen/send data to the
METRO, and can also be used to launch and update code via the
* Four indicator LEDs, on the front edge of the PCB, for easy
debugging. One green power LED, two RX/TX LEDs for the UART, and a red
LED connected to pin PB5
* Easy reprogramming, comes pre-loaded with the Optiboot bootloader,
which is supported by avrdude and only uses 512 bytes.
* Works with all Adafruit shields!
We also include 4 rubber bumpers to keep it from slipping off your
* 53mm x 71mm / 2.1" x 2.8"
* Height (w/ barrel jack): 13mm / 0.5"
* Weight: 19g…more