ATtiny25 Minimal Circuit

This schematic shows several ATtiny25 minimal circuit configurations. The ATtiny25 is shown using its internal 8 MHz RC oscillator, which divided by 8 gives a 1 MHz system clock, and with an external crystal. The ATtiny25 has 2kB flash, 128 bytes of SRAM, and 128 bytes of EEPROM. There are two 8-bit timers, and no 16-bit timers.

ATtiny25 Datasheet

Here you can find the current ATtiny25 datasheet

ATtiny25 Pinout

ATtiny25 Pinout

ATtiny25 Schematic Diagrams

Minimal Circuit

Parts

• U1 ATtiny25 MCU
• R1 10k 1/4W resistor
• SW1 Momentary pushbutton switch
• J1 2x5 ISP connector

Minimal Circuit w/External Crystal

Parts

• U1 ATtiny25 MCU
• C1,C2 27pF ceramic capacitor
• X1 20MHz crystal
• R1 10k 1/4W resistor
• SW1 Momentary pushbutton switch
• J1 2x5 ISP connector