ATMEGA1284P-MU - 128KB Flash 8-Bit AVR MCU 20MHz | Microchip
MPN: ATMEGA1284P-MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.9 | $6.90 |
| 10 | $6.2 | $62.00 |
| 100 | $5.5 | $550.00 |
| 500 | $4.95 | $2,475.00 |
| 1,000 | $4.4 | $4,400.00 |
| 3,000 | $4.1 | $12,300.00 |
ATMEGA1284P-MU Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor in the broader microcontroller (MCU) hierarchy: MCU -> embedded processor -> semiconductor IC. AVR devices achieve throughputs approaching 1 MIPS per MHz by executing most powerful instructions in a single clock cycle, which lets designers run lower clock speeds, reduce EMI, and cut power consumption compared with CISC 8-bit alternatives.
Key features include 128KB of In-System Programmable (ISP) FLASH with Read-While-Write support, the largest SRAM (16KB) in the megaAVR 44-pin family, and picoPower technology for low-power battery designs. Peripherals comprise a Real Time Counter (RTC), three flexible Timer/Counters with compare modes and PWM, two USARTs, a byte-oriented 2-wire interface (TWI/I2C), SPI, an 8-channel 10-bit ADC, and a programmable Watchdog Timer.
Technically, the ATmega1284P uses the Advanced RISC AVR core with 32 general-purpose working registers directly connected to the ALU, giving single-cycle execution. In-system programming via SPI and self-programming boot support simplify field firmware updates without removing the device from the PCB.
Typical applications include industrial automation and sensor acquisition nodes, motor and LED control systems, battery-powered instruments, and hobby/embedded systems such as Arduino-compatible boards via the MightyCore hardware package.
A key design consideration: the 44-VQFN (MU) package requires an exposed-pad ground connection on the PCB land pattern for reliable grounding and thermal dissipation, and the supply range and clock configuration must be matched to BOD settings for safe flash writes.
This page synthesizes distributor availability, drop-in same-package alternatives, and practical design notes not consolidated in the manufacturer datasheet. Pricing shown is estimated as of 2026-09-16.
Drop-in alternatives for ATMEGA1284P-MU 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 ATMEGA1284P-MU (same form factor and footprint) β differing in EEPROM, Flash Memory, Package, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA1284-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA644PA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA644P-20MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324PA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA164PA-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$2.55 / Unit
View Datasheet βATMEGA1284P-AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA1284P-MU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Max CPU Clock | 20 MHz |
| Flash Memory | 128 KB (64K x 16) ISP, Read-While-Write |
| EEPROM | 4 KB |
| SRAM | 16 KB |
| Supply Voltage Range | 2.7 V to 5.5 V |
| I/O Lines | 32 general purpose |
| USART | 2 |
| Timer/Counters | 3 (with compare modes and PWM) |
| Real Time Counter (RTC) | Yes |
| 10-bit ADC | 8 channels |
| TWI (I2C) | 1, byte-oriented 2-wire |
| SPI | 1 |
| Watchdog Timer | Yes, programmable with on-chip oscillator |
| Package | 44-VQFN (7x7 mm) with Exposed Pad |
| Mounting Type | Surface Mount |
| Programming Interface | ISP via SPI, self-programming boot support |
| RoHS Status | Compliant (per Microchip product page) |
ATMEGA1284P-MU 44-vqfn (7x7 mm) with exposed pad Pin Configuration Guide
Pin configuration for ATMEGA1284P-MU (44-vqfn (7x7 mm) with exposed pad 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 ATMEGA1284P-MU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA1284P-MU is suitable for 6 applications: Industrial Automation and Sensor Acquisition, Battery-Powered Portable Instruments, Arduino-Compatible Hobby and Maker Boards, Dual-UART Communication Gateways, Motor and LED Control with PWM, Data Logging with EEPROM and External Storage.
Industrial Automation and Sensor Acquisition
The ATMEGA1284P-MU fits industrial sensor nodes because its 8-channel 10-bit ADC, TWI/I2C interface, and large 16KB SRAM support multi-sensor acquisition with local buffering. Placed as the main controller, it polls I2C sensors via TWI, streams results over USART1 to an RS-485 field bus, and uses Timer/Counter PWM outputs for actuator control. Running at 20 MHz with the Watchdog enabled gives deterministic 1-MIPS-per-MHz throughput, while the 128KB FLASH leaves room for protocol stacks and OTA firmware tables. The 2.7-5.5 V supply accepts industrial 5 V rails directly without a regulator stage, simplifying BOM cost in DIN-rail and panel-mounted equipment.
Recommended
Battery-Powered Portable Instruments
With picoPower technology, the ATMEGA1284P-MU suits battery instruments that must sleep for months between measurements. The core parks in power-down mode woken by the RTC on TOSC pins (32.768 kHz crystal), samples sensors through the 10-bit ADC, computes with the full 16KB SRAM available, and returns to sleep - a duty cycle that dramatically extends battery life versus always-on 8-bit MCUs. The 2.7 V low end of the supply range allows two-cell alkaline or single Li-ion operation. Designers should enable the Brown-Out Detector at an appropriate threshold so FLASH writes never occur during a dying-battery brownout, and use the picoPower-reduced idle currents documented in the Microchip datasheet.
Recommended
Arduino-Compatible Hobby and Maker Boards
The ATmega1284P is a favorite upgrade over ATmega328P platforms because the MightyCore Arduino package (github.com/MCUdude/MightyCore) delivers full IDE support, bootloader, and pin mapping for 44-pin megaAVR devices. The 128KB FLASH hosts large sketches and the 16KB SRAM eliminates the heap-fragmentation crashes common in 2KB-SRAM ATmega328P projects using displays or FAT filesystems. Community builds have even used 1284P boards as pin-extended replacements for 328P designs. On the -MU VQFN variant, hobbyists should prefer breakout boards since the 0.5 mm QFN pitch is challenging for hand soldering; the pin-identical TQFP -AU version is easier to prototype.
Recommended
Dual-UART Communication Gateways
Two independent hardware USARTs make the ATMEGA1284P-MU efficient as a protocol translator: USART0 connects a host PC or HMI while USART1 drives an RS-485/RS-232 field device, each with its own baud-rate generator so mixed speeds (e.g., 115200 baud host, 9600 baud field) run without software UART overhead. The 128KB FLASH stores multiple protocol stacks and lookup tables, and the RTC timestamps events in logging gateways. Interrupt-driven ring buffers fit comfortably in the 16KB SRAM at high throughput. Designers should route RXD1/TXD1 (PD2/PD3) to a transceiver such as an RS-485 part and enable the Watchdog Timer to recover from field-bus lockups.
Recommended
Motor and LED Control with PWM
Three Timer/Counters with compare modes and PWM outputs let the ATMEGA1284P-MU generate multiple synchronized PWM channels for motor drivers, LED dimming, and servo control. Timer1 (16-bit) delivers fine-grained PWM resolution for stepper or DC motor speed loops, while Timer0/Timer2 (8-bit) handle auxiliary channels or RTC duties. The 32 GPIO lines provide direction, enable, and limit-switch interfacing, and the 10-bit ADC reads current-sense resistors for closed-loop control. Drive external MOSFET gate drivers rather than loads directly, since AVR GPIO current is limited; enable dead-time in software when driving H-bridge topologies to prevent shoot-through in power stages.
Recommended
Data Logging with EEPROM and External Storage
The ATMEGA1284P-MU is well suited to standalone loggers: 4KB internal EEPROM holds calibration constants and configuration, the 16KB SRAM buffers high-rate samples, and SPI connects SD-card or FRAM storage for bulk logs. The RTC with a 32.768 kHz crystal provides timestamping, and interrupt-on-pin-change inputs wake the MCU on sensor events. The 128KB FLASH supports self-programming bootloaders so firmware and lookup tables can be updated in the field from the storage medium itself. Design the power path so BOD triggers before VCC collapses below the minimum flash-write voltage, protecting data integrity during battery removal or brownout events.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA1284P-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA1284-MU | ATMEGA644PA-MU | ATMEGA324PA-MU | ATMEGA1284P-AU |
|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) exposed pad | 44-VQFN (7x7) - same footprint | 44-VQFN (7x7) - same footprint | 44-VQFN (7x7) - same footprint | 44-TQFP (10x10) - different footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 128 KB | 64 KB | 32 KB | 128 KB |
| SRAM | 16 KB | 16 KB | 4 KB | 2 KB | 16 KB |
| Max Clock / Performance | 20 MHz / 20 MIPS | 20 MHz / 20 MIPS | 20 MHz / 20 MIPS | 20 MHz / 20 MIPS | 20 MHz / 20 MIPS |
| PicoPower Low-Power Features | Yes | No (standard) | Yes | Yes | Yes |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 5.5 V (PA picoPower) | 1.8 V to 5.5 V (PA picoPower) | 2.7 V to 5.5 V |
| USART Count | 2 | 2 | 2 | 2 | 2 |
Key Differentiators
- Largest memory in the 44-pin megaAVR family (vs ATMEGA644PA-MU)
- picoPower low-power technology (vs ATMEGA1284-MU)
- Compact QFN footprint with exposed pad (vs ATMEGA1284P-AU)
- Dual hardware USART with RTC (vs ATMEGA164PA-MU)
Design Notes
The 44-VQFN (7x7 mm) exposed pad is the primary ground connection. Design the PCB land pattern with a solder-paste window-pane array under the center pad (roughly 4-6 apertures) to limit voiding during reflow, and thermal-stitch the pad to the ground plane with an array of vias. All VCC pins need 100 nF ceramic decoupling within 3 mm plus 10 uF bulk. Follow Microchip AVR QFN application guidance; hand-soldering 0.5 mm pitch QFN is impractical for prototypes - consider the pin-identical TQFP ATMEGA1284P-AU for early builds.
Enable the Brown-Out Detector (BOD) before relying on FLASH or EEPROM writes. Estimated rule of thumb: a 20 MHz core writing self-programmed FLASH must maintain VCC above the low end of the operating range for the entire write cycle (a few milliseconds per page); a decaying supply mid-write corrupts the page. BOD hysteresis plus a 10 uF bulk capacitor typically holds the rail long enough for controlled shutdown logging. Verify exact BOD thresholds and speed/voltage derating in the Microchip datasheet for your clock configuration.
Keep the crystal (up to 20 MHz main oscillator and optional 32.768 kHz RTC crystal on TOSC1/TOSC2) traces under 10 mm with guard ground on both sides, and place load capacitors directly at the pins. Route USART1 (PD2/PD3) away from the ADC input lines on Port A to prevent digital switching coupling into 10-bit analog readings; use AVCC filtering (ferrite plus 100 nF) for the analog supply. If driving RS-485, add TVS protection on the bus side of the transceiver.
Do not assume 20 MHz operation across the full supply range - AVR devices derate maximum clock at low VCC; check the speed-grade curve in the datasheet and either lower f_CPU or raise VCC. Also note the difference between the 'P' (picoPower, higher endurance) and non-P ATmega1284 parts: registers behave nearly identically, but sleep-mode currents differ, so if you migrate firmware from ATMEGA1284-MU, re-verify power measurements rather than trusting previous battery-life calculations.
Compliance Information
RoHS compliant per Microchip product page and distributor listings (DigiKey, Heisener). REACH compliant per standard Microchip product declarations. No AEC-Q100 qualification claimed for the commercial ATmega1284P line.
