ATMEGA8A-AU from Microchip, in a TQFP-32(7x7). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	PD3/INT1	bidirectional	Port D bit 3, bi-directional I/O with programmable internal pull-up. Alternate function: INT1 external interrupt input.
2	PD4/XCK/T0	bidirectional	Port D bit 4, bi-directional I/O with programmable internal pull-up. Alternates: USART external clock (XCK) and Timer/Counter0 external clock input (T0).
3	GND	power_in	Digital ground reference (0V).
4	VCC	power_in	Digital supply voltage, 2.7-5.5V.
5	GND	power_in	Digital ground reference (0V).
6	VCC	power_in	Digital supply voltage, 2.7-5.5V.
7	PB6/XTAL1/TOSC1	bidirectional	Port B bit 6, bi-directional I/O with internal pull-up. Alternates: XTAL1 crystal oscillator input (and internal clock circuit input); TOSC1 asynchronous Timer/Counter2 oscillator input when AS2 bit set.
8	PB7/XTAL2/TOSC2	bidirectional	Port B bit 7, bi-directional I/O with internal pull-up. Alternates: XTAL2 crystal oscillator output (inverting amplifier); TOSC2 asynchronous Timer/Counter2 oscillator when AS2 bit set.
9	PD5/T1	bidirectional	Port D bit 5, bi-directional I/O with internal pull-up. Alternate: Timer/Counter1 external clock input (T1).
10	PD6/AIN0	bidirectional	Port D bit 6, bi-directional I/O with internal pull-up. Alternate: analog comparator positive input (AIN0).
11	PD7/AIN1	bidirectional	Port D bit 7, bi-directional I/O with internal pull-up. Alternate: analog comparator negative input (AIN1).
12	PB0/ICP1	bidirectional	Port B bit 0, bi-directional I/O with internal pull-up. Alternate: Timer/Counter1 input capture (ICP1).
13	PB1/OC1A	bidirectional	Port B bit 1, bi-directional I/O with internal pull-up. Alternate: Timer/Counter1 output compare A (OC1A) PWM output.
14	PB2/SS/OC1B	bidirectional	Port B bit 2, bi-directional I/O with internal pull-up. Alternates: SPI slave select (SS, active low); Timer/Counter1 output compare B (OC1B) PWM output.
15	PB3/MOSI/OC2	bidirectional	Port B bit 3, bi-directional I/O with internal pull-up. Alternates: SPI Master Out / Slave In data (MOSI, also used for ISP programming); Timer/Counter2 output compare (OC2) PWM output.
16	PB4/MISO	bidirectional	Port B bit 4, bi-directional I/O with internal pull-up. Alternate: SPI Master In / Slave Out data (MISO, also used for ISP programming readback).
17	PB5/SCK	bidirectional	Port B bit 5, bi-directional I/O with internal pull-up. Alternate: SPI serial clock (SCK, also used for ISP programming).
18	AVCC	power_in	Analog supply voltage for the A/D Converter, Port C[3:0], and ADC[7:6]. Must be connected externally to VCC (through low-pass filter if ADC is used).
19	ADC6	input	Dedicated analog input channel 6 to the 10-bit ADC (TQFP/QFN only). Powered from analog supply (AVCC).
20	AREF	passive	Analog reference input for the A/D Converter. Typically decoupled with capacitor to AGND.
21	GND	power_in	Analog ground reference (0V); shared/tied to digital GND.
22	ADC7	input	Dedicated analog input channel 7 to the 10-bit ADC (TQFP/QFN only). Powered from analog supply (AVCC).
23	PC0/ADC0	bidirectional	Port C bit 0, bi-directional I/O with internal pull-up. Alternate: ADC channel 0 analog input.
24	PC1/ADC1	bidirectional	Port C bit 1, bi-directional I/O with internal pull-up. Alternate: ADC channel 1 analog input.
25	PC2/ADC2	bidirectional	Port C bit 2, bi-directional I/O with internal pull-up. Alternate: ADC channel 2 analog input.
26	PC3/ADC3	bidirectional	Port C bit 3, bi-directional I/O with internal pull-up. Alternate: ADC channel 3 analog input.
27	PC4/ADC4/SDA	bidirectional	Port C bit 4, bi-directional I/O with internal pull-up. Alternates: ADC channel 4 analog input; TWI (I2C-compatible) serial data (SDA) - open-drain when TWEN set.
28	PC5/ADC5/SCL	bidirectional	Port C bit 5, bi-directional I/O with internal pull-up. Alternates: ADC channel 5 analog input; TWI (I2C-compatible) serial clock (SCL) - open-drain when TWEN set.
29	PC6/RESET	input	Reset input (active low) by default; a low level longer than the minimum pulse length generates a reset even when the clock is not running. If the RSTDISBL fuse is programmed, PC6 becomes a general-purpose I/O with reduced drive.
30	PD0/RXD	bidirectional	Port D bit 0, bi-directional I/O with internal pull-up. Alternate: USART receive data input (RXD).
31	PD1/TXD	bidirectional	Port D bit 1, bi-directional I/O with internal pull-up. Alternate: USART transmit data output (TXD).
32	PD2/INT0	bidirectional	Port D bit 2, bi-directional I/O with internal pull-up. Alternate: INT0 external interrupt input.

Key specifications

Parameter	Value
Manufacturer	Microchip
Package	TQFP-32(7x7)
Category	MCU
Pins	32

Ordering variants

ATMEGA8A-AU
ATMEGA8A-AUR
ATMEGA8A-AUAN
ATMEGA8A-AUANR
ATMEGA8A-AUMU
ATMEGA8A-AUMUR
ATMEGA8A-AUMN
ATMEGA8A-AUMNR
ATMEGA8A-AUPU
ATMEGA8A-AUPN

CAD (KiCad official)

Symbol: ATMEGA8A-AU
Footprint: Package_QFP:LQFP-32_7x7mm_P0.8mm
3D model: TQFP-32(7x7) (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`atmega8a-au.step`	413 KB	You want the bare part, or you mark your own boards.
`atmega8a-au-etched.step`	3.0 MB	You want the part with `ATMEGA8A-AU` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 796 faces against 507 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Microchip datasheet (13 pp, sha256 95842cde9bc8cdd0, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF