The DFRduino Nano USB Microcontroller V3.1 (ATMega 328) is a breadboard - friendly version of the Arduino mini with built - in USB. Similar to the Diecimila electronically, it has more analog input pins and an on - board +5V AREF jumper. It automatically detects and switches to the higher power supply, eliminating the need for a power select jumper. Its pin layout is compatible with the Mini or the Basic Stamp. It can be powered via the mini - B USB connection, a 6 - 20V unregulated external power supply (pin 30), or a 5V regulated external power supply (pin 27), always choosing the highest voltage source. Version 3.0 improved analog port pin mapping for Arduino Nano compatibility, and version 3.1 switched to a Micro USB port. Features include automatic reset during program download, a power - OK blue LED on the bottom, green (TX), red (RX), and orange (L) LEDs, a +5V to AREF jumper, auto - sensing/switching power input, a small mini - B USB for programming and serial monitor (cable not included), an ICSP header for direct program downloads, standard 0.1' spacing DIP (easy for breadboards), and a manual reset switch. Specifications involve a Microcontroller of Atmel Atmega328 - 20AU, operating voltage of 5V, recommended input voltage of 7 - 12V, input voltage limits of 6 - 20V, 14 digital I/O pins (6 with PWM output), 8 analog input pins, 40 mA DC current per I/O pin, 32 KB flash memory (2KB for bootloader), 2 KB SRAM, 1 KB EEPROM, and a 16 MHz clock speed. There's also a WIKI (Arduino Nano V3.1) available. The shipping list includes one DFRduino Nano V3.
Using the DFRduino Nano V3.1 is quite straightforward. First, choose your power source. You can use the mini - B USB connection, a 6 - 20V unregulated external power supply through pin 30, or a 5V regulated external power supply via pin 27. The device will automatically pick the highest voltage source. When programming, the automatic reset feature will make the process smooth. Just connect it to your computer using the small mini - B USB (though you'll need to provide your own cable), and use the ICSP header for direct program downloads. For breadboarding, its standard 0.1' spacing DIP makes it easy to work with. As for the LEDs, the power - OK blue LED on the bottom shows the power status, while the green (TX), red (RX), and orange (L) LEDs give you more information about data transfer and other operations. When it comes to input voltage, stick to the recommended 7 - 12V for the best performance, but it can handle between 6 - 20V. Don't exceed the 40 mA DC current per I/O pin to avoid damaging the device. For maintenance, keep it in a dry and clean environment. If you need to reset the device manually, use the manual reset switch. And always refer to the WIKI (Arduino Nano V3.1) if you have any technical questions.
