ATtiny25/45/85 Datasheet, Pinout, Minimal Circuit, Maximum Frequency Calculator

The ATtiny25/45/85 has 6 programmable I/O pins, and runs off of an internal 8MHz RC oscillator, but also a 4.6MHz oscillator. It has no USART for serial communication, but provides a USI block which can be used as a USART in a pinch. 4 ADC channels and 2 8-bit timers are included as well. Pinout and functionality are similar to the ATtiny13.

The ATtinyx5 series looks to be ideal for motor or power control applications, having 4 ADC channels, and two high frequency PWM outputs with programmable dead time. With an INT0 interrupt, and a useful but less so PCINT0 interrupt one could make a pretty simple DC servo or RC-type servo control.

Power Supply vs. Maximum Frequency

The maximum clock frequency is dependent on the power supply voltage, and the calculator below can help you determine the maximum clock frequency at any power supply voltage.

Maximum Frequency Calculator for ATtiny25/45/85

ATtiny25/45/85 Features
FeatureAttiny24Attiny44Attiny84
Flash 2k4k8k
EEPROM 128B256B512B
RAM 128B256B512B
I/O Pins 6
Interrupts 15
USARTS 0
USI 1
SPI 0
TWI 0
ADC Channels 4
RT Counter (w/osc)0
Timers (8-bit) 2
Timers (16-bit) 1
PWM (8-bit) 2
PWM (16-bit) 0
Price (1's) $1.08$1.17$1.32
CharacteristicValue
Power Consumption (approximate) 1mA + (0.58mA/MHz)
Maximum I/O Current (per pin) 40mA
Maximum I/O Current (total) 200mA

ATtiny25/45/85 Datasheet

Link to ATtiny25/45/85 datasheet from Atmel's website.

ATtiny25/45/85 Pinout

ATtiny85-PU pinout

ATtiny25/45/85 "Minimal" Circuit Diagram

The circuit below shows a programming port. The most minimal circuit would be an ATtinyx5 with no additional parts.

ATtiny25/45/85 minimal schematic diagram