ATMEGA324P-20MUR - 8-bit AVR MCU 20MHz 32KB Flash | Microchip
MPN: ATMEGA324P-20MUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.05 | $30.50 |
| 100 | $2.61 | $261.00 |
| 500 | $2.28 | $1,140.00 |
| 1,000 | $2.02 | $2,020.00 |
| 3,000 | $1.86 | $5,580.00 |
ATMEGA324P-20MUR Overview
An 8-bit AVR ATmega microcontroller is a single-chip computer that integrates a Harvard-architecture RISC processor core, program memory (Flash), data memory (SRAM), nonvolatile storage (EEPROM), and peripherals such as timers, UARTs, SPI, TWI (I2C), and a 10-bit ADC on one die. It sits at the lowest tier of the embedded-systems hierarchy - microcontroller, embedded processor, SoC - making it the workhorse of cost-sensitive embedded control designs.
Key features include the AVR advanced RISC architecture with 131 powerful instructions, most executing in a single clock cycle, enabling true 20 MIPS throughput at 20 MHz. The picoPower technology from the P-series reduces active and sleep-mode current consumption, critical for battery-backed and energy-conscious designs. Read-while-write Flash allows firmware updates during operation, and In-System Programming (ISP) via SPI enables field upgrades without removing the device.
The ATmega324P integrates two 8-bit timers, one 16-bit timer, two USARTs, SPI, TWI, an 8-channel 10-bit ADC, analog comparator, and JTAG (IEEE 1149.1) boundary-scan and debug support - per the Microchip ATmega324P product family documentation. The 44-pin VQFN 7x7 mm footprint suits space-constrained boards while remaining hand-solderable for prototyping.
Typical applications include industrial control panels, building automation nodes, sensor and metering systems, consumer appliances, and embedded instrumentation where 5 V industrial signaling and moderate code density (up to 32 KB) are required.
Design consideration: at 20 MHz the device must be operated at 4.5 V to 5.5 V; ensure your supply rail is 5 V and place 100 nF decoupling on every VCC/AVCC pin pair.
This page synthesizes distributor availability data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, with pricing refreshed as of 2026-09-17.
Drop-in alternatives for ATMEGA324P-20MUR — 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 ATMEGA324P-20MUR (same form factor and footprint) — differing in Package, Flash Memory, Maximum Clock Frequency, Number of I/O, Instruction Set.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA324PA-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA324PB-MU
✅ Drop-In✓ In Stock
$1.35 / Unit
View Datasheet →ATMEGA324P-20MQ
✅ Drop-In✓ In Stock
$4.15 / Unit
View Datasheet →ATMEGA324P-20MQR
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →ATMEGA644PA-MU
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA324P-20MUR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Program Memory Size | 32 KB (16K x 16) Flash |
| EEPROM Size | 1 KB |
| SRAM Size | 2 KB |
| Maximum Clock Frequency | 20 MHz |
| Performance | up to 20 MIPS at 20 MHz |
| Instructions | 131 powerful instructions, most single-cycle |
| Supply Voltage Range | 4.5 V to 5.5 V |
| General Purpose I/O | 32 I/O lines |
| Package | 44-VQFN (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| Flash Programming | In-System Programmable (ISP), read-while-write |
| Low Power Technology | picoPower |
| Debug / Boundary Scan | JTAG (IEEE 1149.1) |
ATMEGA324P-20MUR 44-vqfn (7x7 mm) Pin Configuration Guide
Pin configuration for ATMEGA324P-20MUR (44-vqfn (7x7 mm) 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 ATMEGA324P-20MUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA324P-20MUR is suitable for 6 applications: Industrial Control Panels, Sensor and Metering Systems, Building Automation Nodes, Consumer Appliance Control, Embedded Instrumentation and Test Fixtures, Motor-Adjacent Control Logic.
Industrial Control Panels
The ATmega324P-20MUR fits industrial control panels because its -40C to +85C industrial temperature grade and 4.5 V to 5.5 V supply directly match industrial 5 V signaling standards such as legacy PLC I/O. The 20 MHz core executing up to 20 MIPS handles ladder-logic interpretation, relay sequencing, and communication tasks with margin, while 32 KB Flash and 1 KB EEPROM store application code and configuration retained through power cycles. Dual USARTs let one UART link to a human-machine interface and the other to Modbus RTU field buses, and the 32 GPIO lines drive indicators and read limit switches. Placed on a standard 5 V rail with 100 nF decoupling per VCC pin and TVS protection on field-wired I/O, the 44-VQFN (7x7 mm) footprint keeps panel controller PCBs compact without requiring multilayer stackups.
Recommended
Sensor and Metering Systems
The ATmega324P-20MUR suits energy meters, flow meters, and multi-sensor acquisition nodes thanks to its 8-channel 10-bit ADC, which can be mapped across current-shunt, voltage-divider, and temperature inputs in a single device. The 1 KB EEPROM preserves calibration tables and billing counters without battery backup, and the picoPower process keeps average current low enough for battery-or-shunt-powered meter designs during idle polling. The 20 MHz clock provides headroom for digital filtering and pulse-counting algorithms while two USARTs and TWI connect to displays or a data concentrator. Designers should run the ADC with a filtered AVCC supply and an internal or external 2.56 V/5 V reference, sample synchronously to zero crossings for harmonic accuracy, and use EEPROM wear-leveling so counters are not written at every read cycle in 10+ year service life.
Recommended
Building Automation Nodes
Wall sensors, damper actuators, and HVAC zone controllers benefit from the ATmega324P-20MUR's balance of connectivity and I/O. TWI (I2C) at up to 400 kHz addresses temperature, humidity, and CO2 sensor ICs, one USART links to room displays, and 32 GPIO handles relay drivers, triacs, and DIP switches. The 5 V industrial grade tolerates the noisy supply environment of building wiring, while JTAG supports boundary-scan production testing of assembled boards. The 44-VQFN (7x7 mm) with 0.5 mm pitch lands on two-layer PCBs, keeping node cost low at volumes typical of BAS deployments. In firmware, schedule ADC and communication bursts between sensor reads to exploit picoPower sleep modes, and use the 16-bit timer with input capture for fan tachometer measurement with 1 Hz resolution at typical blade counts.
Recommended
Consumer Appliance Control
Washing machines, coffee systems, and small kitchen appliances use the ATmega324P-20MUR for its combination of robust 5 V operation, adequate memory, and low unit cost. The 32 KB Flash holds menu-driven UI code, motor ramps, and fault logs; 2 KB SRAM supports state machines and display buffers for segmented or small graphic panels. The 10-bit ADC reads NTC temperature probes and water-level pressure sensors, timers generate PWM for triac phase-angle motor control, and the analog comparator provides zero-cross detection with almost no CPU overhead. The 44-VQFN (7x7 mm) SMD package survives wave-free reflow assembly used in appliance manufacturing. Designers should isolate the 5 V logic ground from mains-referenced power sections with optocouplers and maintain creepage distances, and enable the internal brown-out detector to prevent EEPROM corruption during mains brownouts.
Recommended
Embedded Instrumentation and Test Fixtures
Bench instruments, production test fixtures, and data loggers leverage the ATmega324P-20MUR's JTAG boundary-scan for board-level test and its dual USARTs for simultaneous DUT communication and host logging. The 20 MHz/20 MIPS throughput executes CRC checks, pattern generation, and pass/fail scoring in real time, while 1 KB EEPROM stores fixture calibration constants that survive firmware updates. The 10-bit ADC captures analog DUT rails during functional sequences, and the SPI master can drive DACs or relay matrices. The 44-VQFN (7x7 mm) package offers a dense yet reworkable footprint for prototype iterations. Connect MPLAB SNAP or a JTAG ICE to the JTAG header for in-circuit debugging during fixture bring-up, and ground-guard analog traces near the ADC to hold noise below 1 LSB in 5 V-referenced measurements.
Recommended
Motor-Adjacent Control Logic
Fan controllers, gate drivers' supervision, and pump logic use the ATmega324P-20MUR for peripheral timing rather than raw processing. Two 8-bit timers and one 16-bit timer with input capture measure tach pulses, generate PWM for DC fan speed control at 20-25 kHz (above audible range using the 20 MHz clock), and synchronize outputs to zero crossings. The analog comparator with bandgap reference provides brownout or overcurrent trip logic in hardware, and 32 GPIO interfaces keypads, LEDs, and status outputs. Running at 5 V gives high noise immunity against inverter switching transients common in motor cabinets, and the -40C to +85C grade covers enclosure-mounted environments. Use differential RC filtering on tach inputs, keep PWM ground returns separate from analog ground at a single star point, and validate watchdog timeout coverage of worst-case ISR latency.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324P-20MUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PA-MU | ATMEGA324PB-MU | ATMEGA324P-20MQ | ATMEGA324P-20MQR | ATMEGA644PA-MU |
|---|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB |
| SRAM | 2 KB | 2 KB | 4 KB | 2 KB | 2 KB | 4 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| USARTs | 2 | 2 | 3 | 2 | 2 | 2 |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Supply Voltage | 4.5 V to 5.5 V | 1.8 V to 5.5 V (V variant grades) | 1.8 V to 5.5 V (V variant grades) | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V (V variant grades) |
Key Differentiators
- Identical die at active lifecycle with green package (vs ATMEGA324P-20MQ)
- Upgraded peripheral set on same footprint (vs ATMEGA324PB-MU)
- Lower power in same package (vs ATMEGA324P-20MUR)
- Memory headroom without redesign (vs ATMEGA644PA-MU)
Design Notes
The 20 MHz speed grade requires 4.5 V to 5.5 V on VCC; if your rail can droop below 4.5 V during motor start or mains brownout, enable the internal brown-out detector (BOD at 4.3 V) via fuses so the core halts before Flash or EEPROM corruption occurs. Estimated: at 20 MHz with peripherals active, typical active current is on the order of 10-15 mA, so a 100 mA 5 V LDO has ample margin for the MCU plus a few indicator LEDs.
The 44-VQFN (7x7 mm) exposes a die-attach pad under the body that should be soldered to a ground keepout with a via array (typically 4-9 vias) for thermal relief and signal return. Decouple both VCC and AVCC pins with 100 nF ceramics placed within 2 mm of each pin; add a 10 uF bulk capacitor near the device. Route AVCC through an LC filter (ferrite bead plus 100 nF/1 uF) if ADC accuracy matters, keeping analog traces away from PWM and crystal nets.
Do not assume the internal RC oscillator: the 20 MHz UART baud rates and precise PWM frequencies require the CKSEL fuses set for an external 20 MHz crystal with correct startup delay (16K CK + 64 ms for slow-starting resonators). A second pitfall is SPI ISP contention - keep a series 100R on MOSI/SCK to the ISP header if other SPI slaves load the bus during programming. Finally, confirm JTAGEN fuse state: enabling JTAG steals Port C pins 2-5 from general-purpose use.
Compliance Information
Verified web data lists the part as GREEN and RoHS-typical for the -MUR suffix (Microchip green packaging). REACH, halogen-free, and conflict-minerals status not explicitly stated in provided data.