ATtiny13A — Ultra-Low-Cost 8-Bit AVR Microcontroller with 1KB Flash (DIP-8)

Overview

The ATtiny13A is an ultra-compact, ultra-low-cost 8-bit AVR RISC microcontroller manufactured by Microchip Technology (originally Atmel). Housed in an 8-pin through-hole DIP-8 and surface-mount SOIC-8 package, it provides the most minimalist bare-bones AVR processing platform available.

Operating from $1.8\text{V}$ to $5.5\text{V}$ DC with picoPower technology ( $< 0.1\ \mu\text{A}$ sleep current), the ATtiny13A integrates $1\text{ KB}$ Flash ( $1024\text{ Bytes}$ ), $64\text{ Bytes}$ SRAM, $64\text{ Bytes}$ EEPROM, 6 programmable GPIOs, a 4-channel 10-bit ADC, and 2 hardware PWM outputs from its internal 8-bit timer. With dedicated Arduino core support via MicroCore, it is celebrated across DIY electronics communities for powering tactical LED flashlight firmware (Biscotti / Guppydrv / ToyKeeper AMC7135 drivers), simple servo decoders, RGB LED mood candles, and tiny smart battery monitors.

Quick reference


CPU Core	8-bit AVR RISC Architecture
Package	8-pin DIP (DIP-8) / 8-pin SOIC / 10-pin QFN
Internal Oscillators	$9.6\text{ MHz}$ / $4.8\text{ MHz}$ / $128\text{ kHz}$ calibrated RC
Flash Memory	$1024\text{ Bytes}$ ( $1\text{ KB}$ ) non-volatile storage
SRAM	$64\text{ Bytes}$ internal RAM
EEPROM	$64\text{ Bytes}$ non-volatile data EEPROM
Supply Voltage Range	$1.8\text{ V}$ to $5.5\text{ V}$ DC ( $4.5\text{V} \dots 5.5\text{V}$ for $20\text{MHz}$ )
Deep Sleep Current	$< 0.1\ \mu\text{A}$ at $1.8\text{V}$ (Power-Down Mode)
GPIO Count	6 Programmable I/O lines (PB0 through PB5)
Analog Peripherals	4-channel 10-bit ADC (15 ksps) + Analog Comparator
Timer / PWM	1x 8-bit Timer/Counter with 2 PWM channels (`OC0A`, `OC0B`)
Programming Interface	In-System Programming (ISP via SPI: MOSI, MISO, SCK, RESET)

Pinout (DIP-8 Package)

text

                            ┌───┴───┐
      (Active-Low/ADC0) PB5 1│ 1   8 │ VCC (+1.8V to +5.5V)
       (ADC3/CLKI/PCINT3) PB3 2│ATtiny│ 7 PB2 (SCK/ADC1/PCINT2)
       (ADC2/CLKO/PCINT4) PB4 3│ 13A  │ 6 PB1 (MISO/OC0B/PCINT1)
                          GND 4│DIP-8 │ 5 PB0 (MOSI/OC0A/PCINT0)
                            └───────┘

Pin	Name	Type	Description
1	`PB5`	GPIO / Reset	Active-LOW Reset / `ADC0` / `PCINT5` / `dW` (debugWIRE)
2	`PB3`	GPIO / Analog	`ADC3` / External Clock Input (`CLKI`) / `PCINT3`
3	`PB4`	GPIO / Analog	`ADC2` / Clock Output (`CLKO`) / `PCINT4`
4	`GND`	Power	Common Ground reference ( $0\text{ V}$ )
5	`PB0`	GPIO / Digital	`MOSI` (ISP) / `OC0A` (PWM Output 0) / `AIN0` / `PCINT0`
6	`PB1`	GPIO / Digital	`MISO` (ISP) / `OC0B` (PWM Output 1) / `AIN1` / `PCINT1`
7	`PB2`	GPIO / Digital	`SCK` (ISP) / `ADC1` / `T0` (Timer Clock) / `PCINT2`
8	`VCC`	Power	Supply Voltage ( $+1.8\text{ V}$ to $+5.5\text{ V}$ DC)

Minimal Circuit & ISP Flashing Hookup

text

   Arduino as ISP / USBasp Programmer
   ┌────────────────────────────────┐
   │ 5V / 3.3V ─────────────────────┼─────────┬──────────────► [Pin 8: VCC]
   │                                │         │                     ATtiny13A
   │                                │   [ 100nF Cap ]               DIP-8
   │                                │         │
   │ GND ───────────────────────────┼─────────┼──────────────► [Pin 4: GND]
   │ RESET (Pin 10 on Arduino) ─────┼─────────┼──────────────► [Pin 1: PB5 / RESET]
   │ MOSI (Pin 11 on Arduino) ──────┼─────────┼──────────────► [Pin 5: PB0 / MOSI]
   │ MISO (Pin 12 on Arduino) ──────┼─────────┼──────────────► [Pin 6: PB1 / MISO]
   │ SCK  (Pin 13 on Arduino) ──────┼─────────┼──────────────► [Pin 7: PB2 / SCK]
   └────────────────────────────────┘

Comparison: ATtiny13A vs ATtiny85

Parameter	ATtiny13A	ATtiny85
Pinout	Identical 8-pin DIP / SOIC	Identical 8-pin DIP / SOIC
Flash Memory	$1024\text{ Bytes}$ ( $1\text{ KB}$ )	$8192\text{ Bytes}$ ( $8\text{ KB}$ )
SRAM	$64\text{ Bytes}$	$512\text{ Bytes}$
EEPROM	$64\text{ Bytes}$	$512\text{ Bytes}$
Timers	1x 8-bit Timer (2 PWM)	2x Timers (1x 8-bit, 1x High-Speed 64MHz 8-bit)
Price	$\approx \$ 0.30 - $0.50$	$\approx \$ 1.10 - $1.50$

Common mistakes

RAM exhaustion with standard C libraries: With only $64\text{ Bytes}$ of RAM, avoid using sprintf, heavy string manipulations, or large global arrays. Keep local variables minimal.
Flashing with stock Arduino core instead of MicroCore: Standard Arduino core overhead will exceed the $1024\text{ Byte}$ Flash limit instantly. Install MicroCore by MCUdude, which strips runtime bloat and allows full digitalWrite(), analogRead(), and delay() within a few hundred bytes.
Disabling the RESET pin (RSTDISBL fuse): Disabling Reset to gain Pin 1 as PB5 prevents future SPI programming. High-Voltage Serial Programming (HVSP with 12V on Reset) will be required to erase and restore the chip.

Notes

Arduino Core: Supported via the open-source MicroCore board package.