ATtiny261/461/861 Datasheet, Pinout, Minimal Circuit, Maximum Frequency Calculator

The ATtinyx61 is a 20-pin device with 16 pins available for I/O. It is similar in I/O to the ATtiny26, but with the addition of pin change interrupts. It is pin-compatible. Certain peripherals can be clocked at 32 or 64MHz. One PWM uses the high-speed 8/10-bit timer to generate a true fast PWM.

The x61 is available in 2kB, 4kB, and 8kB versions.

Power Supply vs. Maximum Frequency

The ATtiny261 has a unique clock, featuring an internal RC clock that runs at 8MHz, with a PLL that takes the fast I/O clock up to 64MHz! The maximum CPU frequency is 20MHz with an external crystal.

Maximum Frequency Calculator for ATtiny261/461/861

ATtiny261/461/861 Features
Flash 2k4k8k
EEPROM 128B256B512B
RAM 128B256B512B
I/O Pins 16
Interrupts 19
ADC Channels 11
RT Counter (w/osc)0
Timers (8-bit) 21
Timers (16-bit) 0
Timers (16-bit) 0
PWM (8-bit) 2
PWM (16-bit) 0
Price (1's) $1.54$1.76$2.54
Power Consumption (approximate) 1mA + (0.58mA/MHz)
Maximum I/O Current (per pin) 40mA
Maximum I/O Current (total) 200mA (PDIP)


  1. There are one 8/16-bit timer and one 8/10-bit high-speed timer.

ATtiny261/461/861 Datasheet

Link to ATtiny261/461/861 datasheet from Atmel's website.

ATtiny261/461/861 Pinout

ATtiny261-PU pinout

ATtiny261-MU pinout

ATtiny261/461/861 "Minimal" Circuit Diagram

The circuit below shows a basic standalone ATtiny261. The resistor on the RESET line is not required because there is an internal pullup on the line.

ATtiny261/461/861 minimal schematic diagram