> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official retailers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt

# Adafruit METRO 328 with Headers - ATmega328

**Type:** Product page · **SKU:** ADA2488 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia)
**Page:** https://core-electronics.com.au/adafruit-metro-328-with-headers-atmega328.html ([markdown](https://core-electronics.com.au/adafruit-metro-328-with-headers-atmega328.html.md))

## Retired product

This product is retired and no longer available for purchase. Search the catalogue for an alternative.

## How to buy

- **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works)
- **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt
## Description

Adafruit sure love the ATmega328 here at Adafruit, and Adafruit use them *a lot* for Adafruit's 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 Adafruit need to go small, Adafruit use a [Pro Trinket 3V](https://core-electronics.com.au/adafruit-pro-trinket-3v-12mhz.html) or [5V](https://core-electronics.com.au/adafruit-pro-trinket-5v-16mhz.html), but when size isn't as much of a concern, and an USB-serial converter is required, Adafruit 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 Adafruit's [Metro without Headers.](https://core-electronics.com.au/adafruit-metro-328-without-headers-atmega328.html)

METRO is the culmination of years of playing with AVRs: Adafruit 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 bootloader
- **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](https://github.com/Optiboot/optiboot), which is supported by avrdude and only uses 512 bytes.
- **[Works with all Adafruit shields!](https://www.adafruit.com/categories/21)**
 
They also include 4 rubber bumpers to keep it from slipping off your desk. [Metro shown with Adafruit's 12x capacitive touch shield attached just to demonstrate the headers, but that shield is not included!](https://core-electronics.com.au/adafruit-12-x-capacitive-touch-shield-for-arduino-mpr121.html)

**Mac & Windows People! Don't forget to grab & install the FTDI VCP drivers from FTDI to make the COM/Serial port show up right! The default drivers may not support this FTDI chip!**

## Technical Details

**Detailed specifications:**

- ATmega328 microcontroller with Optiboot (UNO) Bootloader
- USB Programming and debugging via the well-supported genuine FTDI FT231X
- Input voltage: 7-9V (a 9VDC power supply is recommended)
- 5V regulator can supply peak ~800mA as long as the die temp of the regulator does not exceed 150\*C
- 3.3V regulator can supply peak ~150mA as long as the die temp of the regulator does not exceed 150\*C
- 5V logic with 3.3V compatible inputs, can be converted to 3.3V logic operation
- 20 Digital I/O Pins: 6 are also PWM outputs and 6 are also Analog Inputs
- 6-pin ICSP Header for reprogramming
- 32KB Flash Memory - 0.5K for bootloader, 31.5KB available after bootloading
- 16MHz Clock Speed
- Compatible with "Classic" and "R3" Shields
- Adafruit Black PCB with gold plate on pads
- 53mm x 71mm / 2.1" x 2.8"
- Height (w/ barrel jack): 13mm / 0.5"
- Weight: 19g
- Derivative of "Arduino UNO R3 Reference design"
- [Open source hardware files on github!](https://github.com/adafruit/Adafruit-METRO-328-PCB)
 
Revision History:

- As of August 31, 2015 Adafruit have updated the Metro's headers to be *slightly* taller so that they are the same height as classic 'non-SMT' headers for a better shield-fit

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/2/4/2488-09.jpg)