Digispark DIY: The smallest USB Arduino




Digispark is an ATtiny85 based microcontroller development board come with USB interface. Coding is similar to Arduino, and it use the familiar Arduino IDE for development.

Digispark is copyrighted by Digistump LLC (digistump.com) and the full license is here: http://digistump.com/wiki/digispark/policy

The smallest USB Arduino




Specification:
Support for the Arduino IDE 1.0+ (OSX/Win/Linux)
Power via USB or External Source – 5v or 7-35v (automatic selection)
On-board 500ma 5V Regulator
Built-in USB (and serial debugging)
6 I/O Pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB)
8k Flash Memory (about 6k after bootloader)
I2C and SPI (vis USI)
PWM on 3 pins (more possible with Software PWM)
ADC on 4 pins
Power LED and Test/Status LED (on Pin0)

 

Step 2: Burning bootloader to ATTINY85

Like Arduino, Digispark require a bootloader to be running on ATTINY85. The bootloader will occupied 2KB flash memory.

Download bootloader
1. Download Micronucleus bootloader for ATTINY85
2. Extract the file (micronucleus-t85-master.zip) to any folder
3. You can find the bootloader file at micronucleus-t85-master\firmware\releases folder
4. Use micronucleus-1.06.hex for the bootloader

Burning bootloader to ATTINY85
You must use the correct fuses bit for the bootloader

Extended: 0xFE
High: 0xDD
Low: 0xE1

Note: The above fuse bit will not enable reset as I/O, so you can have only 5 I/O instead of 6 I/O. I’m still try to figure out on how to set it to 6 I/O

I’m using AVRISP MKII In System Programmer and AVR Studio software for burning bootloader.

The smallest USB Arduino schematic

Step 3: Installing Digispark USB driver

Digispark use USB to communicate with computer, so your computer must install Digispark USB driver
1. Download Arduino for Digispark which come with USB driver
2. Extract the file (DigisparkArduino-Win32-1.0.4-March29.zip)  to any folder
3. Execute DigisparkArduino-Win32\DigisparkWindowsDriver\InstallDriver.exe to start installing the USB driver

Major Components in Project

Prerequisite

AVRISP MKII In-System Programmer
ATTINY85 Microcontroller
2 x 3.6V zener diode
2 x 68 ohm resistor
1 x 1.5K resistor
USB cable (get from broken mouse or keyboard)
Some wires

For more detail: Digispark DIY: The smallest USB Arduino

We recommend EasyEDA for electronic circuit design.
From Schematic Drawing to PCB Production, Just Need One Tool
Cheap PCB Prototype: 10 pcs 2 layers only $10, quick delivery, 100% E-test







This Post / Project can also be found using search terms:

  • smallest mouse circuit board
  • digispark arduino library
  • digispark as usb to serial
  • digispark atting85 arduino pwm motor project
Clip to Evernote

Leave a Comment

(Spamcheck Enabled)

Read previous post:
Using DS1307 and DS3231 real-time clock modules with Arduino

We keep getting requests on how to use DS1307 and DS3231 real-time clock modules with Arduino from various sources –...

Close
Scroll to top