The ATtiny84 is part of the ATtiny series of AVR microcontrollers (MCUs) by Microchip and its design is based on RISC architecture. The ATtiny84 is a very small and low-cost microcontroller which can be programmed with an Arduino. This chip has a low power consumption with a voltage range from 1.8V to 5.5V and is available in various packages such as SOIC and PDIP.

The ATiny84 chip is a 8-bit processor which has 14 pins, 12 I/O pins and features:

• 8K Flash
• 512 Bytes of EEPROM
• 512 Bytes of SRAM
• Maximum Frequency 20MHz
• 8 ADC channels
• 4 PWM channels
• 8 bit and 16 bit timer/counter with two PWM channels

Like the AVR ATtiny85 microcontroller, the ATtiny84 is a great little chip for small projects where size is critical.