> **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

# Arduino USB 2 Serial Micro

**Type:** Product page · **SKU:** CE00331
**Page:** https://core-electronics.com.au/arduino-usb-2-serial-micro.html ([markdown](https://core-electronics.com.au/arduino-usb-2-serial-micro.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

The USB Serial Adapter has an onboard micro-USB connector and 5 pins including RX (for receiving data from the computer) and TX (for transmitting data). 5V, Ground and a Reset pin are also exposed.

Status lights include power, RX and TX activity.

The adapter can easily connect to the Arduino Mini.

An onboard polyfuse limits the current to 500mA and protects the host computer from short circuits.

The ATmega16U2 firmware source code is available. The ATmega16U2 is loaded with a DFU bootloader, refer to the DFU mode section. You can then use Atmel's FLIP software (Windows) or the DFU programmer (Mac OS X and Linux) to load a new firmware if required. You can use the ISP header with an external programmer (overwriting the DFU bootloader). See this user-contributed tutorial for more information.

### Schematic & Reference Design

EAGLE files: arduino-USB-2-Serial-micro-reference-design.zip
Schematic: arduino-USB-2-Serial-micro-schematic.pdf

### Automatic (Software) Reset

The USB Serial connector is designed in a way that allows it to reset an attached board by software running on a connected computer.The external reset line mirrors the DTR line of the virtual serial device on the computer. It's typically connected to the reset line of the connected board allowing the board to reset on upload.

This setup has other implications. When the board is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). While it is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened. If a sketch running on the board receives one-time configuration or other data when it first starts, make sure that the software with which it communicates waits a second after opening the connection and before sending this data.

The pinouts on the connector are compatible with a standard FTDI

### DFU mode

First connect the Arduino to the computer using the USB port.

To reprogram the atmega16u2, you must put the chip into DFU (Device Firmware Update) mode.

Shortcut briefly the pin 5 and 6 of the ICSP header as shown:

![Arduino USB 2 Serial Micro](https://core-electronics.com.au/media/wysiwyg/product_info/A000107-ArduinoUSB2serialMICRO-flat_det.jpg)

The pinouts on the connector are compatible with a standard FTDI header (as well as the Adafruit and Sparkfun USB-Serial adapters).

### Conformity Declaration

CE

## Guides for this product

- [Programming with USB-Serial Converters](https://core-electronics.com.au/guides/digital-electronics/programming-with-usb-serial-converters/)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/a/r/arduino-usb-2-serial-micro.jpg)