ATMEGA329-16AU - 8-bit AVR MCU 16MHz 32KB Flash LCD | Microchip
MPN: ATMEGA329-16AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.16 | $11.16 |
| 10 | $10.5 | $105.00 |
| 100 | $9.85 | $985.00 |
| 500 | $9.15 | $4,575.00 |
| 1,000 | $8.45 | $8,450.00 |
ATMEGA329-16AU Overview
An AVR ATmega microcontroller is an 8-bit RISC-based MCU belonging to the broader microcontroller and embedded processor family. AVR devices execute most of their 130-plus powerful instructions in a single clock cycle, giving high code efficiency from small program memory. Microcontrollers of this class combine CPU, program Flash, data SRAM, EEPROM, and peripherals such as timers, USART, ADC, and - in this device - a complete LCD driver on one silicon die, forming the heart of an embedded system.
Key features include 32 KB of self-programming ISP Flash with read-while-write capability, 1 KB EEPROM, 2 KB SRAM, and 54 general purpose I/O lines. A JTAG interface provides boundary-scan, on-chip debugging, and programming. The integrated LCD controller with internal contrast control drives segment LCDs directly, a capability uncommon in general-purpose MCUs of this era, and three flexible timers plus a 10-bit ADC round out the analog and timing peripherals.
Architecturally, the device uses the AVR enhanced RISC core with 32 general purpose working registers directly connected to the ALU, allowing most single-cycle execution. In-system programmable Flash enables firmware updates on the assembled board through SPI or JTAG, reducing rework cost in production.
Typical applications include utility metering with segment LCD displays, industrial panels and human-machine interfaces, and battery-powered or line-powered instrumentation requiring direct LCD drive, timers, and ADC acquisition.
Design consideration: at 16 MHz the part must run from 4.5 V to 5.5 V; for 3 V systems choose a V speed grade variant and reduce the clock accordingly, and always place 100 nF decoupling on both VCC pins.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA329-16AU β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATMEGA329-16AU (same form factor and footprint) β differing in Package, LCD Controller, Core Architecture, Operating Temperature, ADC.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA329P-16AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA329-16AI
β Drop-Inβ In Stock
Contact for price
View Datasheet βATMEGA325PA-AUR
β Drop-Inβ In Stock
$3.9 / Unit
View Datasheet βATMEGA325-16AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$2.4 / Unit
View Datasheet βATMEGA165P-16AU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$5.1 / Unit
View Datasheet βATMEGA329-16AU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Maximum Clock Frequency | 16 MHz |
| Flash Program Memory | 32 KB (16K x 16) |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| Supply Voltage Range | 4.5 V to 5.5 V |
| General Purpose I/O Lines | 54 |
| Package | 64-TQFP (14x14 mm), 0.8 mm pitch |
| LCD Controller | On-chip segment LCD controller with internal contrast control |
| JTAG Interface | Yes (boundary-scan, on-chip debug, programming) |
| In-System Programming | Yes (ISP Flash, read-while-write) |
| General Purpose Working Registers | 32 |
| Instructions | 130+ powerful instructions, most single-clock cycle |
| Mounting Type | Surface Mount |
| Life Cycle Stage | Active |
ATMEGA329-16AU 64-tqfp (14x14 mm), 0.8 mm pitch Pin Configuration Guide
Pin configuration for ATMEGA329-16AU (64-tqfp (14x14 mm), 0.8 mm pitch package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATMEGA329-16AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA329-16AU is suitable for 6 applications: Utility Metering and Energy Panels, Industrial HMI and Control Panels, Battery-Powered Instrumentation (V-grade designs), Thermostats and Climate Controls, POS Terminals and Price Displays, Automotive and Appliance Sub-Systems (industrial grade).
Utility Metering and Energy Panels
Electricity, water, and gas meters are the classic home of the ATmega329 family because the on-chip LCD controller drives the segment display directly with internal contrast control, eliminating an external LCD driver IC and its wiring. The ATMEGA329-16AU contributes 32 KB of self-programming ISP Flash for metering firmware and tariff tables, 2 KB SRAM for accumulation buffers, and 1 KB EEPROM for storing calibration and billing data through power interruptions. Placed on a 5 V rail with the ADC reading shunt or transformer current samples, the 16 MHz AVR core executes accumulation and display-multiplexing loops with ample margin. Using EEPROM write endurance for periodic logging, and the JTAG port for factory calibration, keeps the whole meter front-end on one MCU die, reducing BOM count and board area in sealed meter enclosures.
Recommended
Industrial HMI and Control Panels
Industrial control panels need many I/O lines, robust timers, and a readable local display. The ATMEGA329-16AU supplies 54 GPIO in a single 64-TQFP, so switches, relays, indicators, and a segment LCD all connect without port expanders. The three flexible timers handle keypad debouncing, PWM actuator control, and system tick simultaneously, while the 10-bit ADC reads potentiometers and sensors at 5 V full scale - convenient because industrial sensors are commonly 0-5 V, needing no front-end scaling. Operating from 4.5 V to 5.5 V at 16 MHz matches legacy 5 V industrial rails directly, simplifying retrofit designs into existing cabinets. The JTAG interface supports boundary-scan for production test of the assembled panel and on-chip debugging during commissioning, which shortens bring-up time for custom machine-interface boards built in low-to-medium volumes.
Recommended
Battery-Powered Instrumentation (V-grade designs)
Although the -16AU grade targets 5 V systems, the ATmega329 architecture is the platform for portable instruments: the same firmware scales to the V-grade family members that run at lower supply. In portable gauges and handheld testers, the segment LCD with internal contrast control draws minimal current compared with backlit graphic displays, extending battery life substantially. The 1 KB EEPROM preserves user settings and last-measurement values across battery swaps, and the AVR sleep modes cut idle current to microamp levels when the instrument waits for a trigger. Designers prototype on the 5 V ATMEGA329-16AU where debug tooling and signal levels are convenient, then port to the V variant for the production battery build - the shared footprint and pinout make this a solder-and-boot change rather than a redesign, protecting schedules in short development cycles.
Recommended
Thermostats and Climate Controls
HVAC thermostats and climate controllers combine a segment LCD, temperature measurement, relay actuation, and long field life - all strengths of the ATMEGA329-16AU. The on-chip LCD controller shows setpoint and measured temperature without a display driver, the 10-bit ADC reads NTC thermistors through a simple divider at the native 5 V rail, and timers generate relay PWM or compressor anti-cycle delays. The 32 KB Flash holds scheduling tables and menu logic with room for firmware updates delivered through the self-programming ISP Flash bootloader, enabling feature upgrades on installed units. The 1 KB EEPROM stores user schedules and hysteresis calibrations across power outages. Because commercial thermostats run continuously for a decade, the JTAG debug path and Microchip's long-lifecycle support for the AVR family make maintenance straightforward throughout the product's service life.
Recommended
POS Terminals and Price Displays
Retail price displays, small point-of-sale terminals, and ticketing units traditionally use segment LCDs for cost and readability under shop lighting. The ATMEGA329-16AU drives such displays directly from its integrated LCD controller with internal contrast control, keeping the display legible without backlight power. Its 54 GPIO lines interface keypad matrices, printers, communication gates, and indicator LEDs from one controller, and the USART links the terminal to back-office systems. The 32 KB ISP Flash accommodates protocol stacks and localization strings, while the 1 KB EEPROM retains device identity and transaction counters through power failures. Running at 16 MHz from a 5 V supply provides deterministic timing for receipt printing and keypad scanning, and the self-programming Flash lets service teams update firmware in the field over the serial link without replacing the MCU.
Recommended
Automotive and Appliance Sub-Systems (industrial grade)
White goods and non-safety automotive sub-systems - dishwasher panels, charger status units, seat-memory modules - combine a display with numerous switches and loads. The industrial-temperature sibling ATMEGA329-16AI, pin-identical to this part, covers -40C to +85C ambient conditions found in garages and appliance cabinets, letting one PCB design serve both commercial and harsher environments. On this platform the ATmega329's LCD controller drives the cycle-status display, the ADC reads potentiometer and NTC inputs, and 54 GPIO handle door interlocks, heaters, and motor relays through driver transistors. The 5 V tolerant architecture suits automotive 12 V rails via a simple regulator, and the EEPROM logs fault codes across power cycles for service diagnostics. Using JTAG boundary-scan during board production catches solder defects on the dense 64-pin footprint before assembly into sealed enclosures.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA329-16AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA329P-16AU | ATMEGA329-16AI | ATMEGA325PA-AUR | ATMEGA165P-16AU |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 1 KB |
| Max Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 20 MHz (PA grade) | 16 MHz |
| LCD Controller | Yes, with internal contrast control | Yes | Yes | Yes (fewer segments) | Yes (fewer segments) |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V (16 grade) | 4.5 V to 5.5 V | 1.8 V to 5.5 V (PA picoPower) | 4.5 V to 5.5 V (16 grade) |
Key Differentiators
- Integrated LCD controller with internal contrast control (vs ATMEGA324P-20AUR)
- Double the memory of the smaller family sibling (vs ATMEGA165P-16AU)
- PicoPower upgrade path without redesign (vs ATMEGA329P-16AU)
Design Notes
The ATMEGA329-16AU requires 4.5 V to 5.5 V for the 16 MHz speed grade. Do not attempt 3.3 V operation at 16 MHz - core timing violations cause erratic execution. If the board also contains 3.3 V peripherals, add level shifting or choose a PA/V picoPower variant. Place 100 nF ceramic decoupling capacitors at each VCC/AVCC pin pair, plus a 10 uF bulk capacitor near the regulator, and tie AVCC to VCC through an LC filter when ADC accuracy matters.
For the 64-TQFP (0.8 mm pitch), use a solder-mask-defined land pattern per IPC-7351 guidance and verify with the Microchip packaging drawing before release. Route the JTAG pins (TCK, TMS, TDI, TDO) to a 2x5 header even if debugging is optional - the cost is trivial and in-field diagnostics via boundary-scan have repeatedly saved recalls. Keep the LCD segment traces short and, if the display is remote, guard them with ground to prevent ghost segments from capacitive coupling.
Two frequent mistakes on ATmega329 designs: first, leaving JTAGEN fuse programmed when the JTAG pins are needed as GPIO - the four JTAG lines are not usable as ports until the fuse is cleared via ISP programming, so verify early. Second, EEPROM wear: meters that log every second can exhaust the 100k write endurance within months; wear-level by cycling write addresses or throttling writes. Also confirm brown-out detection fuse settings for 5 V operation (around 2.7 V or 4.0 V BOD level) to prevent Flash corruption during slow supply decay.
Compliance Information
The AU suffix denotes Microchip/Atmel lead-free packaging. Full RoHS/REACH declarations should be pulled from the Microchip product page before compliance sign-off.
