ATMEGA324P-20MQ - 8-bit AVR MCU 32KB 20MHz VQFN-44 | Microchip
MPN: ATMEGA324P-20MQ β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.87 | $5.87 |
| 10 | $5.4 | $54.00 |
| 100 | $4.95 | $495.00 |
| 500 | $4.55 | $2,275.00 |
| 1,000 | $4.15 | $4,150.00 |
ATMEGA324P-20MQ Overview
A microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory, data memory and peripherals on one die. The ATmega324P sits within the AVR ATmega family of 8-bit MCUs, which in turn belongs to the broader category of embedded microcontrollers used in power management, industrial control and consumer systems. AVR cores execute most instructions in a single clock cycle, and this device implements 131 powerful instructions with 32 general-purpose working registers for fully static operation.
Key features include 32 KB of in-system self-programmable Flash with read-while-write capability, allowing firmware updates without halting execution; picoPower low-power technology for sleep currents in the microamp class; a real-time counter plus multiple flexible timers; and JTAG plus In-Circuit Serial Programming (ICSP) for debugging and programming through only two device I/O pins and reset. Throughput is approximately 20 MIPS at the full 20 MHz clock.
Architecturally, the AVR uses a Harvard structure with separate program and data buses, giving fast, deterministic instruction fetch. The P suffix denotes the picoPower feature set, which adds power-reduction registers that can clock-gate individual peripherals to cut consumption in idle, power-save, power-down and standby sleep modes.
Typical applications include industrial automation nodes, sensor and data-logging systems, motor and LED control, and consumer appliances that need moderate memory and rich I/O in a compact surface-mount footprint.
When designing, reserve the RESET line for ICSP and consider the newer ATMEGA324PA for new designs, as Microchip designates it as the newer device in this family.
This page synthesizes distributor pricing, drop-in family alternatives, pinout and practical design notes not found in a single manufacturer datasheet view.
Drop-in alternatives for ATMEGA324P-20MQ 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 ATMEGA324P-20MQ (same form factor and footprint) β differing in Flash Memory, EEPROM, Package, SRAM, ADC.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA324PA-20MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324P-20MU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$3.8 / Unit
View Datasheet βATMEGA164P-20MQ
β Drop-Inβ In Stock
$2.96 / Unit
View Datasheet βATMEGA644P-20MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324PA-20MUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324P-20MQ Maximum Ratings & Electrical Characteristics
| Core | AVR 8-bit RISC |
| Core Size | 8-bit |
| Maximum Clock Frequency | 20 MHz |
| Flash Memory | 32 KB (16K x 16) ISP |
| EEPROM | 1 KB |
| SRAM | 2 KB |
| Supply Voltage | 5 V |
| Number of I/O | 32 general purpose I/O lines |
| Package | 44-VQFN (7x7 mm), exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature Range | Extended temperature (M suffix) |
| Instruction Set | 131 powerful instructions |
| Working Registers | 32 general purpose registers |
| Low Power Technology | picoPower |
| Programming / Debug | ICSP, JTAG |
| Timers / RTC | Real time counter plus three flexible timers |
| RoHS Status | Green package (per FindIC listing) |
ATMEGA324P-20MQ Pin Configuration
| Pin 1 | PB5 (SCK) β Port B bit 5, SPI serial clock |
| Pin 2 | PB6 β Port B bit 6 |
| Pin 3 | PB7 β Port B bit 7 |
| Pin 4 | RESET β Reset input, active low; used by ICSP |
| Pin 5 | VCC β Digital supply voltage (5 V) |
| Pin 6 | GND β Digital ground |
| Pin 7 | XTAL2 β Crystal oscillator output |
| Pin 8 | XTAL1 β Crystal oscillator input / external clock |
| Pin 9 | PD0 (RXD) β Port D bit 0, UART receive |
| Pin 10 | PD1 (TXD) β Port D bit 1, UART transmit |
| Pin 11 | PD2 (INT0) β Port D bit 2, external interrupt 0 |
| Pin 12 | PD3 (INT1) β Port D bit 3, external interrupt 1 |
| Pin 13 | PD4 (OC1B) β Port D bit 4, Timer1 output compare B |
| Pin 14 | PD5 (OC1A) β Port D bit 5, Timer1 output compare A |
| Pin 15 | PD6 (ICP1) β Port D bit 6, Timer1 input capture |
| Pin 16 | PD7 (OC2A) β Port D bit 7, Timer2 output compare A |
| Pin 17 | PC0 (SCL) β Port C bit 0, TWI clock |
| Pin 18 | PC1 (SDA) β Port C bit 1, TWI data |
| Pin 19 | PC2 (TCK) β Port C bit 2, JTAG test clock |
| Pin 20 | PC3 (TMS) β Port C bit 3, JTAG test mode select |
| Pin 21 | PC4 (TDO) β Port C bit 4, JTAG test data out |
| Pin 22 | PC5 (TDI) β Port C bit 5, JTAG test data in |
| Pin 23 | PC6 (TOSC1) β Port C bit 6, RTC oscillator input |
| Pin 24 | PC7 (TOSC2) β Port C bit 7, RTC oscillator output |
| Pin 25 | AVCC β Analog supply voltage for ADC |
| Pin 26 | AREF β ADC analog reference |
| Pin 27 | GND β Analog ground |
| Pin 28 | PA0 (ADC0) β Port A bit 0, ADC channel 0 |
| Pin 29 | PA1 (ADC1) β Port A bit 1, ADC channel 1 |
| Pin 30 | PA2 (ADC2) β Port A bit 2, ADC channel 2 |
| Pin 31 | PA3 (ADC3) β Port A bit 3, ADC channel 3 |
| Pin 32 | PA4 (ADC4) β Port A bit 4, ADC channel 4 |
| Pin 33 | PA5 (ADC5) β Port A bit 5, ADC channel 5 |
| Pin 34 | PA6 (ADC6) β Port A bit 6, ADC channel 6 |
| Pin 35 | PA7 (ADC7) β Port A bit 7, ADC channel 7 |
| Pin 36 | PB0 (SS) β Port B bit 0, SPI slave select |
| Pin 37 | PB1 β Port B bit 1 |
| Pin 38 | PB2 (MOSI) β Port B bit 2, SPI master data out |
| Pin 39 | PB3 (MISO) β Port B bit 3, SPI master data in |
| Pin 40 | PB4 (OC0) β Port B bit 4, Timer0 output compare |
| Pin 41 | PB5 β Port B bit 5 (duplex pin position per package) |
| Pin 42 | PB6 β Port B bit 6 (duplex pin position per package) |
| Pin 43 | PB7 β Port B bit 7 (duplex pin position per package) |
| Pin 44 | GND β Ground |
Typical Applications
ATMEGA324P-20MQ is suitable for 6 applications: Industrial Automation Nodes, Sensor and Data-Logging Systems, Motor and LED Control, Consumer Appliances and Home Electronics, Networking and Communication Interfaces, Test, Measurement and Debug Probes.
Industrial Automation Nodes
The ATMEGA324P-20MQ fits factory automation nodes such as sensor multiplexers, valve controllers and small PLC I/O modules because its 32 GPIO lines across four bidirectional ports interface directly with relays, optocouplers and limit switches, while 32 KB Flash holds protocol stacks like Modbus RTU with room to spare. The extended-temperature VQFN-44 package survives harsh cabinet environments, and the real-time counter plus three flexible timers generate precise PWM or scheduling without CPU intervention. ICSP programming allows field firmware updates through a two-wire header, reducing maintenance cost in installed equipment.
Recommended
Sensor and Data-Logging Systems
In battery-backed data loggers and environmental monitoring nodes, the picoPower feature set of the ATMEGA324P-20MQ is the deciding factor: power-reduction registers clock-gate unused peripherals and multiple sleep modes cut average current between wake-up events. The 1 KB EEPROM retains calibration and event counters through power loss, and the 10-channel-capable port A feeds an external ADC for analog channels. With 2 KB SRAM the device buffers logged samples before writing to external flash over SPI, and the 20 MHz core compresses or timestamps data quickly during short active windows.
Recommended
Motor and LED Control
The ATMEGA324P-20MQ suits fan, pump and LED lighting controllers that need multiple independent PWM channels. Its timers can drive complementary outputs with hardware dead-time behavior coordinated in firmware, while port B and port D pins route direction and enable signals to H-bridge drivers. The 5 V supply matches common gate-driver logic thresholds, eliminating level shifters, and the 44-pin VQFN provides enough I/O for current-sense inputs, encoder quadrature channels and fault feedback on one chip. At 20 MHz, current-loop inner calculations execute well within typical 10-20 kHz PWM periods for small motor control.
Recommended
Consumer Appliances and Home Electronics
Appliance control boards - coffee machines, air handlers, small ovens - benefit from the ATMEGA324P-20MQ's combination of 32 KB Flash for UI logic, menu structures and fault handling, plus 32 I/O lines for keys, displays, buzzers and load relays. The green VQFN-44 package supports RoHS-driven consumer compliance requirements, and the read-while-write Flash lets the device store user settings in program memory pages at runtime. JTAG and ICSP access through a small connector enables factory programming and end-of-line testing without sockets, keeping the finished PCB fully sealed and washable.
Recommended
Networking and Communication Interfaces
The ATMEGA324P-20MQ works as a protocol bridge and gateway controller in RS-485, LIN and simple Ethernet-adjacent subsystems. Its 20 MHz AVR core handles 115.2 kbps UART traffic with headroom, and 2 KB SRAM buffers packet streams for framing and CRC checks. Port C pins double as JTAG for boundary-scan production test of dense boards. Because Flash supports self-programming, the device can store secondary firmware images and perform bootload-driven updates from a host, an important feature for remotely deployed communication modules where physical access is costly.
Recommended
Test, Measurement and Debug Probes
Bench instruments, signal generators and programming pods use the ATMEGA324P-20MQ for its deterministic single-cycle AVR execution and rich timer set: precise frequency output, event capture and PWM reference signals are generated in hardware while the core manages the user interface. The 44-pin VQFN footprint keeps probe PCBs compact, and the extended-temperature rating tolerates warm enclosures near power sections. ICSP plus JTAG lets instrument makers ship self-test firmware and update calibration routines in the field. Port A handles analog front-end control lines to external converters or programmable-gain amplifiers.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA324P-20MQ β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA324PA-20MU | ATMEGA324P-20MU | ATMEGA164P-20MQ | ATMEGA644P-20MU |
|---|---|---|---|---|---|
| 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 |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 16 KB | 64 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 1 KB | 4 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Power Technology | picoPower (P die) | picoPower, newer PA die (lower current) | picoPower (P die) | picoPower (P die) | picoPower (P die) |
| Temperature Suffix | MQ (extended, green) | MU (industrial) | MU (industrial) | MQ (extended, green) | MU (industrial) |
| Pin-to-Pin Compatibility | Reference (44-pin MLF/VQFN) | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible |
Key Differentiators
- Twice the Flash of the smaller family sibling (vs ATMEGA164P-20MQ)
- Extended-temperature green package (vs ATMEGA324P-20MU)
- Cost-optimized versus larger memory family members (vs ATMEGA644P-20MU)
Design Notes
The 44-VQFN 7x7 mm package has an exposed die pad that must be soldered to a grounded copper array on the PCB for mechanical reliability and thermal dissipation. Microchip application notes for MLF/VQFN assemblies recommend via stitching under the pad and a stencil aperture pattern of roughly 50-70% coverage to prevent floating. Place 100 nF ceramic decoupling capacitors at VCC and AVCC within 2-3 mm of the pins, and connect AVCC to VCC through a low-pass LC filter when ADC accuracy matters.
The RESET pin is shared with ICSP programming - never load it with a strong pull-down or a large capacitor, which blocks in-system programming. JTAG on port C is enabled by default in fresh parts; if you need PC2-PC7 as general-purpose I/O, clear the JTAGEN fuse (a parallel connection to JTAGICE is required to recover). Also note the JTD bit in the MCUCSR register can disable JTAG at runtime. Verify fuse settings (clock source, brown-out, BODLEVEL) before deploying, since wrong clock fuses can permanently seem to brick the device.
This is a 5 V device; at 20 MHz the datasheet specifies the higher voltage operating point, so power it from a regulated 5 V rail with brown-out detection enabled via fuses for reliable reset during supply dips. Estimated: with picoPower sleep modes and peripheral clock-gating, average system current in duty-cycled battery applications can drop by an order of magnitude versus always-running operation - schedule work in short active bursts and enter power-down between samples. For lowest power, evaluate the newer ATMEGA324PA die in the same footprint.
Compliance Information
Q package suffix denotes green (lead-free/RoHS) per FindIC and Microchip ordering conventions. Formal REACH, halogen-free and conflict-minerals declarations must be obtained from Microchip.
