ATMEGA323-8PC - 8-Bit AVR MCU, 32KB Flash, 8MHz | Atmel
MPN: ATMEGA323-8PC β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.56 | $7.56 |
| 10 | $7.18 | $71.80 |
| 100 | $6.83 | $683.00 |
| 500 | $6.49 | $3,245.00 |
| 1,000 | $6.17 | $6,170.00 |
ATMEGA323-8PC Overview
A microcontroller unit (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals on one die, sitting below application processors and above simple logic ICs in the embedded-system hierarchy. The AVR family uses an advanced RISC architecture with a Harvard memory structure, meaning program and data buses are separate and most instructions execute in a single clock cycle.
Key features include 131 powerful instructions (most single-cycle), up to 16 MIPS throughput at 16MHz-class operation, and 32 general-purpose working registers directly connected to the ALU. Peripheral set includes Brown-out Detect/Reset (BOD), Power-on Reset (POR), PWM timers, a Watchdog Timer (WDT), plus I2C (TWI), SPI, and UART/USART serial interfaces. The 32KB Flash supports In-System Programming, enabling field firmware updates without removing the chip.
Architecturally, the ATmega323 executes code from Flash at up to 1 MIPS per MHz, letting designers trade clock speed for power consumption. The JTAG-compatible pin arrangement on port C supports boundary-scan and on-chip debugging on related family members, while the large 40-PDIP package offers generous 0.1-inch pin spacing ideal for prototyping, ZIF sockets, and through-hole assembly.
Typical applications include industrial control and automation nodes, educational and hobby embedded platforms, legacy equipment maintenance where socketed MCUs simplify replacement, and instrumentation requiring 5V-tolerant I/O and the 4.5V to 5.5V industrial supply range.
Design consideration: the -8PC suffix specifies 8MHz speed grade, 0C to +70C commercial temperature rating, and 5V PDIP packaging. For 3V systems or wider temperature ranges, select the L-suffix (2.7V to 5.5V) or I-suffix (industrial temperature) variants instead.
This page synthesizes distributor pricing, drop-in alternatives from the same AVR family, pinout data, and practical design notes beyond what the manufacturer datasheet provides.
Drop-in alternatives for ATMEGA323-8PC 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 ATMEGA323-8PC (same form factor and footprint) β differing in Package, Core Architecture, Maximum Clock Frequency, Operating Temperature, Throughput.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA32-16PU
β Drop-Inβ In Stock
$3.68 / Unit
View Datasheet βATMEGA32-16PI
β Drop-Inβ In Stock
$2.75 / Unit
View Datasheet βATMEGA323L-8PC
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA163-8PC
β Drop-Inβ In Stock
$3.2 / Unit
View Datasheet βATMEGA324P-20PU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA323-8PC Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Program Memory Size | 32KB (16K x 16) Flash |
| Program Memory Type | In-System Programmable Flash |
| SRAM Size | 2KB (2K x 8) |
| EEPROM Size | 1KB |
| Maximum Clock Frequency | 8MHz |
| Supply Voltage Range | 4.5V to 5.5V |
| Instruction Count | 131 instructions |
| Peak Throughput | Up to 16 MIPS |
| Communication Interfaces | I2C, SPI, UART/USART |
| Peripherals | Brown-out Detect/Reset, POR, PWM, WDT |
| Package | 40-PDIP (DIP-40) |
| Mounting Type | Through-Hole |
| Series | AVR ATmega |
| RoHS Status | unknown (legacy Atmel part) |
| Packaging | Tube |
ATMEGA323-8PC Pin Configuration
| Pin 1 | PB0 (T0/XCK) β Port B bit 0 / Timer0 clock input / USART external clock |
| Pin 2 | PB1 (T1) β Port B bit 1 / Timer1 clock input |
| Pin 3 | PB2 (AIN0/INT2) β Port B bit 2 / Analog comparator positive input / External interrupt 2 |
| Pin 4 | PB3 (AIN1) β Port B bit 3 / Analog comparator negative input |
| Pin 5 | PB4 (SS) β Port B bit 4 / SPI slave select |
| Pin 6 | PB5 (MOSI) β Port B bit 5 / SPI master output, slave input |
| Pin 7 | PB6 (MISO) β Port B bit 6 / SPI master input, slave output |
| Pin 8 | PB7 (SCK) β Port B bit 7 / SPI serial clock |
| Pin 9 | RESET β Active-low reset input |
| Pin 10 | VCC β Digital supply voltage (4.5V to 5.5V) |
| Pin 11 | GND β Ground |
| Pin 12 | XTAL2 β Crystal oscillator output |
| Pin 13 | XTAL1 β Crystal oscillator input / external clock input |
| Pin 14 | PD0 (RXD) β Port D bit 0 / USART receive input |
| Pin 15 | PD1 (TXD) β Port D bit 1 / USART transmit output |
| Pin 16 | PD2 (INT0) β Port D bit 2 / External interrupt 0 |
| Pin 17 | PD3 (INT1) β Port D bit 3 / External interrupt 1 |
| Pin 18 | PD4 (OC1B) β Port D bit 4 / Timer1 output compare B / PWM |
| Pin 19 | PD5 (OC1A) β Port D bit 5 / Timer1 output compare A / PWM |
| Pin 20 | PD6 (ICP1) β Port D bit 6 / Timer1 input capture |
| Pin 21 | PD7 (OC2) β Port D bit 7 / Timer2 output compare / PWM |
| Pin 22 | PC0 (SCL) β Port C bit 0 / TWI (I2C) serial clock |
| Pin 23 | PC1 (SDA) β Port C bit 1 / TWI (I2C) serial data |
| Pin 24 | PC2 (TCK) β Port C bit 2 / JTAG test clock |
| Pin 25 | PC3 (TMS) β Port C bit 3 / JTAG test mode select |
| Pin 26 | PC4 (TDO) β Port C bit 4 / JTAG test data output |
| Pin 27 | PC5 (TDI) β Port C bit 5 / JTAG test data input |
| Pin 28 | PC6 (TOSC1) β Port C bit 6 / Timer oscillator input (32.768kHz) |
| Pin 29 | PC7 (TOSC2) β Port C bit 7 / Timer oscillator output |
| Pin 30 | AVCC β Analog supply voltage for ADC |
| Pin 31 | GND β Ground |
| Pin 32 | AREF β Analog reference voltage for ADC |
| Pin 33 | PA0 (ADC0) β Port A bit 0 / ADC channel 0 |
| Pin 34 | PA1 (ADC1) β Port A bit 1 / ADC channel 1 |
| Pin 35 | PA2 (ADC2) β Port A bit 2 / ADC channel 2 |
| Pin 36 | PA3 (ADC3) β Port A bit 3 / ADC channel 3 |
| Pin 37 | PA4 (ADC4) β Port A bit 4 / ADC channel 4 |
| Pin 38 | PA5 (ADC5) β Port A bit 5 / ADC channel 5 |
| Pin 39 | PA6 (ADC6) β Port A bit 6 / ADC channel 6 |
| Pin 40 | PA7 (ADC7) β Port A bit 7 / ADC channel 7 |
Typical Applications
ATMEGA323-8PC is suitable for 6 applications: Industrial Control and Automation, Embedded Education and Prototyping, Legacy Equipment Repair and Maintenance, Instrumentation and Data Acquisition, Motor Control and PWM Systems, Consumer and Security Devices.
Industrial Control and Automation
The ATMEGA323-8PC suits industrial control nodes because its 4.5V to 5.5V supply range matches legacy 5V industrial logic rails, and its Brown-out Detect and Watchdog Timer provide the fault recovery that unattended equipment demands. The 131-instruction AVR core delivers roughly 1 MIPS per MHz, so an 8MHz clock yields about 8 MIPS - ample for relay sequencing, sensor polling, and Modbus-style UART communication. The 1KB EEPROM stores configuration and calibration data through power cycles, while the 32KB Flash supports In-System Programming for field firmware updates without desoldering. The through-hole DIP-40 package also simplifies socketed replacement during line maintenance.
Recommended
Embedded Education and Prototyping
The ATmega323 remains popular in teaching environments because the 40-pin PDIP package has 0.1-inch pin spacing that fits breadboards, ZIF sockets, and wire-wrap prototyping without adapters. Students can program the 32KB Flash in-system via SPI and experiment with I2C, SPI, and UART peripherals using only a crystal, a 5V supply, and a few decoupling capacitors. The 2KB SRAM is large enough for C-language projects with floating-point routines, and the 8MHz speed grade is forgiving of long breadboard traces that would break signal integrity at higher clocks. Its low cost and socketed nature make burned-out chips a trivial, teachable replacement exercise.
Recommended
Legacy Equipment Repair and Maintenance
For service organizations maintaining legacy industrial and medical equipment designed in the early 2000s, the ATMEGA323-8PC is frequently the specified socketed MCU. Where the original firmware binary cannot be recompiled, replacing with the exact MPN preserves bit-exact behavior. Where recompilation is possible, the pin-compatible ATMEGA32-16PU provides a modern, actively manufactured substitute at the same DIP-40 footprint. The AVR's EEPROM retention and in-system programming allow recalibration constants to be read from a failed unit and restored into the replacement, minimizing downtime on 5V-tolerant control boards.
Recommended
Instrumentation and Data Acquisition
The ATmega323 integrates an 8-channel 10-bit ADC whose reference can be driven from the AREF pin (pin 32) or the internal reference, supporting sensor measurement chains in 5V instrumentation. Its UART/USART links instruments to PCs and loggers, the TWI (I2C) bus reads EEPROMs and RTCs, and the SPI port drives high-speed ADCs and display drivers. Timer/PWM channels (OC1A, OC1B, OC2) generate control waveforms for heaters, pumps, and lamps. At 8MHz the core executes approximately 8 MIPS, sufficient to sample, filter, and stream data over UART at 115200 baud while servicing a watchdog-supervised control loop.
Recommended
Motor Control and PWM Systems
The ATMEGA323's three hardware PWM outputs - OC1A and OC1B from the 16-bit Timer/Counter1 and OC2 from the 8-bit Timer/Counter2 - make it effective for DC motor and lighting control. Hardware PWM generation offloads timing from the CPU, leaving the 8 MIPS core free to run PID algorithms and communicate over UART or SPI. The input capture unit (ICP1) measures feedback frequency or pulse width from encoders and tachometers with hardware precision. With a 4.5V to 5.5V supply and 5V logic I/O, it interfaces directly to MOSFET gate drivers such as typical TC4420-class drivers without level shifting.
Recommended
Consumer and Security Devices
Security panels, access-control readers, and simple consumer appliances of the ATmega323 era use its keypad-scannable 8-bit ports, UART link to modems or RS-485 transceivers, and EEPROM for storing user codes that must survive power loss. Brown-out detection prevents corrupted writes during brownout events - essential when nonvolatile credentials are being updated. The 32KB Flash accommodates larger feature sets such as LCD menu drivers and multi-protocol communication stacks, while the static design allows the clock to be throttled down for battery-backed standby modes. Socketed DIP-40 mounting allows field security updates by swapping programmed chips.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA323-8PC β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA32-16PU | ATMEGA32-16PI | ATMEGA323L-8PC | ATMEGA163-8PC | ATMEGA324P-20PU |
|---|---|---|---|---|---|---|
| Package | 40-PDIP | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) |
| Max Clock Frequency | 8MHz | 16MHz | 16MHz | 8MHz | 8MHz | 20MHz |
| Flash Memory | 32KB | 32KB | 32KB | 32KB | 16KB | 32KB |
| SRAM | 2KB | 2KB | 2KB | 2KB | 1KB | 2KB |
| Supply Voltage | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 2.7V to 5.5V | 4.0V to 5.5V | 4.5V to 5.5V (picoPower) |
| Lifecycle Status | Obsolete | Active | Active | Obsolete | Obsolete | Active |
| RoHS Compliance | unknown (legacy) | Compliant | Compliant | unknown (legacy) | unknown (legacy) | Compliant |
Key Differentiators
- True 5V through-hole platform with socketed DIP-40 (vs ATMEGA324P-20PU)
- Wider supply window within the same family (vs ATMEGA323L-8PC)
- Double the memory of its predecessor at the same clock (vs ATMEGA163-8PC)
Design Notes
On DIP-40 AVR designs, connect VCC (pin 10) and AVCC (pin 30) to the 5V rail with separate 100nF ceramic decoupling capacitors placed within 10mm of each pin, and tie both GND pins (11, 31) to a solid ground net. Never leave AVCC unconnected even if the ADC is unused - the datasheet requires AVCC within 0.3V of VCC. For crystal operation, mount a crystal between XTAL1/XTAL2 with two 22pF load capacitors close to pins 12-13 to guarantee oscillator startup at 8MHz.
The -8PC suffix caps operation at 8MHz and 0C to +70C (commercial grade). Running the part above 8MHz violates the speed grade and may cause marginal instruction execution at low temperature. Also, the RESET pin (9) must not be left floating - fit a 10k pull-up to VCC so Brown-out Reset recovery is deterministic. When programming in-system, hold RESET low via the programmer; SPI programming is disabled if an external SPI device on the shared PB4-PB7 bus loads MISO excessively - use series resistors on the SPI bus.
Estimated: a typical ATmega323 at 8MHz and 5V consumes roughly 5-15mA active (per AVR family datasheet figures), so total board power including I/O loads should be budgeted below 300mW for the MCU itself; no heatsink or thermal design is required. Power the ADC from AVCC with an RC filter (10R + 10uF) from the digital rail to improve ADC noise performance. If battery backup or standby is planned, note the standard part is not optimized for low power - the ATMEGA323L or picoPower ATmega324P is the better fit.
Compliance Information
Legacy Atmel part predating RoHS enforcement; compliance data not published in current distributor listings. Pin-compatible active parts (ATMEGA32-16PU, ATMEGA324P-20PU) are RoHS compliant.
