ATtiny is a family of microcontrollers developed by Atmel beginning in the late 1990s (later Microchip Technology acquired Atmel in 2016). These chips have a modified Harvard architecture 8-bit RISC processor core. The smallest in their AVR family of microcontrollers are the ATtiny series (8-bit core and fewer features, fewer I/O pins, and less memory than other AVR series).

Features

The entire ATtiny microcontroller family doesn't have any of the following features: USB peripheral, DMA controller, Crypto engine, or external memory bus.

The following table summarizes common features of the ATtiny microcontrollers, for easy comparison. This table is not meant to be an unabridged feature list.

Notes

• Package column - the number after the dash is the number of pins in the package, DIP means PDIP (Plastic DIP) package with 0.3-inch row-to-row, SOwww means SOIC package with a case width of 'www' in thousandth of an inch, some packages may be known by alternate names.
• UART/I²C/SPI columns - green cell means a dedicated peripheral, yellow cell means a multi-feature peripheral that is chosen by setting configuration bits. Most USART peripherals support a minimum choice between UART or SPI, where as some might support additional choices, such as LIN, IrDA, RS-485.
• Timers column - recent families add a 12-bit timer, plus a 16-bit Real Time Counter (RTC) that is driven by a 32.768KHz clock (feature designated with 'R' in the table).
• ADC chans column - the total number of analog channels that are multiplex into the ADC input. Most parts have one ADC, a few have two ADC.
• Pgm/Dbg column - "in circuit" flash programmming and debugging protocols. ISP means In-System Programmable protocol, uses SPI to program the internal flash. dW means debugWIRE protocol. UPDI means Unified Program and Debug Interface protocol.

Abbreviations

• TWI: Many of Atmels microcontrollers contain built-in support for interfacing to a two-wire bus, called Two-Wire Interface. This is essentially the same thing as the I²C interface by Philips, but that term is avoided in Atmel's documentation due to trademark issues.
• USI: Universal Serial Interface (not to be confused with USB). The USI is a multi-purpose hardware communication module. With appropriate software support, it can be used to implement an SPI,^[71] I²C^[72][73] or UART^[74] interface.

Timeline

The following table lists each ATtiny microcontroller by the year of the first release date of each datasheet.

Note: The top and bottom rows need research to determine their correct year.

• Atmel tinyAVR Fast and Code Efficient Flyer
• Microchip 8-bit AVR MCU product selector
• ATMEL tinyAVR product selector^{[dead link]}
• All tinyAVR parts in a spreadsheet - EDN Magazine, September 8, 2014.