Digispark Attiny microcontrollers implementation

Introduction

The Digispark is an Attiny85 based microcontroller, and much less well known than Arduino. But considering their price, it seems interesting to learn how to program them.

Digispark microcontrollers features:

Attiny85 based microcontroller (Digispark):

• Support Arduino IDE 1.0+ (OSX/Win/Linux)
• Power via USB or External Source – 5v or 12v
• On-board 500ma 5V Regulator
• Built-in USB
• 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)
• 512B EEPROM, 512-Byte SRAM
• I2C and SPI (vis USI)
• PWM on 3 pins (more possible with Software PWM)
• ADC on 4 pins
• Power LED and Test/Status LEDLF, HF full band.

Attiny167 based microcontroller (Digispark pro):

• Compatible with Arduino IDE 1.5 (OSX/Win/Linux)
• USB programming, USB device emulation, USB-CDC virtual serial port emulation
• 16 Mhz AVR MCU – using a true 16Mhz precision crystal
• 16KB Flash Memory (14.5K+ after bootloader)
• 512B EEPROM, 512-Byte SRAM
• Serial over USB debugging and communication!
• 14 i/o Pins (2 shared with USB)
• I2C, true SPI, UART, LIN, and USI
• ADC on 10 pins
• 3 PWM Channels (which can be assigned to a selection of pins)
• Power via USB, or External Source – 5v or 6-16v (automatic selection)
• On-board button that can be used as a reset, program, or user button – or can be disabled to use that pin as general i/o – without changing the bootloader
• On-board 500ma 5V regulator
• Power LED and Test/Status LED (on Pin 1)
  Breadboard compatible pin out/spacing (the three side header pins are only for legacy shield support).