# ATmega32A-AU chip: specs and pinout

> 8-bit AVR microcontroller in a 44-lead TQFP surface-mount package: 32 KB flash, 2 KB SRAM, 1 KB EEPROM, 32 I/O lines. Bare chip, needs a custom board…

[HTML version](https://soldr.ai/docs/boards/atmega32a-au)

[Docs](https://soldr.ai/docs) / [Boards](https://soldr.ai/docs/boards)

8-bit AVR microcontroller in a 44-lead TQFP surface-mount package: 32 KB flash, 2 KB SRAM, 1 KB EEPROM, 32 I/O lines. Bare chip, needs a custom board or a TQFP adapter.

Every value cites its sourceOfficial pinout

[Buy on Compoden](https://compoden.com/products/atmega-32a-au-tqfp-44-pin-microcontroller)

## Specs

| Spec | Value | Source |
|---|---|---|
| Operating voltage | 2.7 V to 5.5 V | source Features, Operating Voltages |
| Speed grade | 0 to 16 MHz | source Features, Speed Grades |
| Operating temperature | -40 C to 85 C | source Section 28.2 DC Characteristics conditions (TA = -40C to 85C) |
| Flash / SRAM / EEPROM | 32 KB / 2 KB / 1 KB | source Introduction; Features |
| Programmable I/O lines | 32 | source Features, I/O and Packages |
| ADC | 8-channel 10-bit; 8 single-ended; 7 differential channels in TQFP package only | source Features, Peripheral Features |
| PWM channels | 4 | source Features, Peripheral Features |
| Serial interfaces | USART, SPI, two-wire serial interface, JTAG | source Features |
| Active current | 0.6 mA at 1 MHz, 3 V, 25 C | source Features, Power Consumption |
| Power-down current | < 1 uA at 3 V, 25 C | source Features, Power Consumption |

## Power

| | Value | Source |
|---|---|---|
| Supply | 2.7 V to 5.5 V | source Features, Operating Voltages and Power Consumption |
| Current | 0.6 mA active at 1 MHz, 3 V, 25 C; < 1 uA power-down | source Features, Operating Voltages and Power Consumption |

## Pinout

Bare chip, no module board. The pin table is the 44-lead TQFP figure from the chip data sheet (names as written there). The sheet notes the bottom pad of the QFN/MLF package should be soldered to ground; the TQFP has no such pad. A custom board or TQFP adapter is needed; no adapter is part of this listing.

| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1 | PB5 (MOSI) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 2 | PB6 (MISO) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 3 | PB7 (SCK) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 4 | RESET | | | source Section 1 Figure 1-1, TQFP/MLF |
| 5 | VCC | | | source Section 1 Figure 1-1, TQFP/MLF |
| 6 | GND | | | source Section 1 Figure 1-1, TQFP/MLF |
| 7 | XTAL2 | | | source Section 1 Figure 1-1, TQFP/MLF |
| 8 | XTAL1 | | | source Section 1 Figure 1-1, TQFP/MLF |
| 9 | PD0 (RXD) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 10 | PD1 (TXD) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 11 | PD2 (INT0) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 12 | PD3 (INT1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 13 | PD4 (OC1B) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 14 | PD5 (OC1A) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 15 | PD6 (ICP1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 16 | PD7 (OC2) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 17 | VCC | | | source Section 1 Figure 1-1, TQFP/MLF |
| 18 | GND | | | source Section 1 Figure 1-1, TQFP/MLF |
| 19 | PC0 (SCL) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 20 | PC1 (SDA) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 21 | PC2 (TCK) | | JTAG pin; the sheet lists a JTAG interface on port C | source Section 1 Figure 1-1, TQFP/MLF |
| 22 | PC3 (TMS) | | JTAG pin; the sheet lists a JTAG interface on port C | source Section 1 Figure 1-1, TQFP/MLF |
| 23 | PC4 (TDO) | | JTAG pin; the sheet lists a JTAG interface on port C | source Section 1 Figure 1-1, TQFP/MLF |
| 24 | PC5 (TDI) | | JTAG pin; the sheet lists a JTAG interface on port C | source Section 1 Figure 1-1, TQFP/MLF |
| 25 | PC6 (TOSC1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 26 | PC7 (TOSC2) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 27 | AVCC | | | source Section 1 Figure 1-1, TQFP/MLF |
| 28 | GND | | | source Section 1 Figure 1-1, TQFP/MLF |
| 29 | AREF | | | source Section 1 Figure 1-1, TQFP/MLF |
| 30 | PA7 (ADC7) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 31 | PA6 (ADC6) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 32 | PA5 (ADC5) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 33 | PA4 (ADC4) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 34 | PA3 (ADC3) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 35 | PA2 (ADC2) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 36 | PA1 (ADC1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 37 | PA0 (ADC0) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 38 | VCC | | | source Section 1 Figure 1-1, TQFP/MLF |
| 39 | GND | | | source Section 1 Figure 1-1, TQFP/MLF |
| 40 | PB0 (XCK/T0) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 41 | PB1 (T1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 42 | PB2 (INT2/AIN0) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 43 | PB3 (OC0/AIN1) | | | source Section 1 Figure 1-1, TQFP/MLF |
| 44 | PB4 (SS) | | | source Section 1 Figure 1-1, TQFP/MLF |

## Build with it
Project ideas for the ATmega32A-AU chip. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.

- [A custom circuit board around an ATmega 32A-AU that reads a soil moisture sensor and a light sensor and shows both on a 16x2 I2C LCD](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20custom%20circuit%20board%20around%20an%20ATmega%2032A-AU%20that%20reads%20a%20soil%20moisture%20sensor%20and%20a%20light%20sensor%20and%20shows%20both%20on%20a%2016x2%20I2C%20LCD): Port A pins PA0 to PA7 are the 10-bit ADC inputs and PC0/PC1 are the two-wire interface (SCL/SDA). A 5 V board matches the 2.7-5.5 V range. Programmed over its SPI pins.
- [Soil-moisture pump controller](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20custom%20circuit%20board%20around%20an%20ATmega%2032A-AU%20that%20waters%20a%20plant%20by%20switching%20a%20small%20pump%20through%20a%20relay%20module%20when%20a%20soil%20moisture%20sensor%20reads%20dry): One ADC input reads the sensor and one pin drives the relay module. The pump needs its own supply sized for it, not the chip&#x27;s pin. A learning project.
- [Pan-tilt platform with a joystick](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20custom%20circuit%20board%20around%20an%20ATmega%2032A-AU%20that%20moves%20a%20two-servo%20pan-tilt%20bracket%20from%20a%20joystick): Two ADC inputs read the joystick and the chip has four PWM channels (OC0, OC1A, OC1B, OC2). Power the servos from their own 5 V supply and join the grounds.
- [Stopwatch with a 4-digit display](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20custom%20circuit%20board%20around%20an%20ATmega%2032A-AU%20that%20runs%20a%20stopwatch%20on%20a%20TM1637%204-digit%20display%20with%20a%20start%2Fstop%20button): Any free port pins can drive the display&#x27;s two-wire clock and data lines; a 5 V supply keeps logic levels matched.

## Common mistakes

- Treating port C pins PC2 to PC5 as free I/O: the JTAG interface (TCK, TMS, TDO, TDI) shares them, so keep that in mind before using them as plain I/O (source: [link](https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega32A-Datasheet-Complete-DS40002072A.pdf), Features: JTAG interface; pinout Figure 1-1)
- AVCC outside the allowed window: AVCC must not differ more than 0.3 V from VCC (source: [link](https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega32A-Datasheet-Complete-DS40002072A.pdf), ADC chapter)
- Using the 40-pin DIP pin numbers on this 44-lead TQFP: the pin numbers differ between packages (source: [link](https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega32A-Datasheet-Complete-DS40002072A.pdf), Section 1 Figure 1-1)

## Not covered by the official source

- Listing names the TQFP-44 package, so the TQFP table is used; the 40-pin DIP table in the same sheet differs.
- JTAG enable/disable fuse behaviour is not covered; the JTAG mistake line relies on the Features list and the pinout figure only.
- Typical current at 16 MHz is not given on this page.

## Sources

- [link](https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega32A-Datasheet-Complete-DS40002072A.pdf) (Microchip DS40002072A, ATmega32A megaAVR Data Sheet Complete, 2018)