ATMEGA1284P-PU - 128KB AVR MCU 20MHz 40-PDIP | Microchip
MPN: ATMEGA1284P-PU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.65 | $8.65 |
| 10 | $7.9 | $79.00 |
| 100 | $7.15 | $715.00 |
| 500 | $6.6 | $3,300.00 |
| 1,000 | $6.05 | $6,050.00 |
ATMEGA1284P-PU Overview
An AVR ATmega microcontroller is a Harvard-architecture 8-bit processor that executes most instructions in a single clock cycle, sitting at the entry level of the microcontroller hierarchy (MCU -> 8-bit MCU -> AVR ATmega family). It integrates program Flash, data SRAM, EEPROM, timers, USARTs, and ADC on one die, making it a complete embedded control system in a single through-hole or SMD package.
Key differentiating features include the largest SRAM in its class at 16 KB, dual USARTs for two independent serial links, three flexible timer/counters with compare modes and PWM outputs, an 8-channel 10-bit ADC, and a byte-oriented Two-Wire Interface (TWI/I2C). The P suffix denotes picoPower technology for low active and sleep current, important for battery-powered designs.
Architecturally, the ATmega1284P pairs its enhanced RISC core with 32 general-purpose working registers, all directly connected to the ALU, eliminating intermediate register transfers. Read-While-Write Flash allows self-programming and bootloader firmware updates. The real-time counter with separate oscillator supports RTC clocking from a 32.768 kHz crystal.
Typical applications include 3D printer controller boards (notably the RepRap/Sanguinololu ecosystem), hobbyist and educational Arduino-compatible builds via MightyCore, and legacy industrial control retrofits where the through-hole DIP-40 footprint is required for repairability and socketed replacement.
When designing with this part, note that Flash self-write timing and brown-out reset settings must be configured via fuse bits, and at 20 MHz a 5 V supply is required per the datasheet speed-grade table.
This page synthesizes verified distributor pricing, drop-in family alternatives, complete 40-pin pinout data, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA1284P-PU 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-PU (same form factor and footprint) β differing in ADC, Core Architecture, EEPROM, Package, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA644P-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA644A-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324P-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA324PA-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA1284P-PU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Flash Memory | 128 KB (64K x 16) ISP Flash |
| SRAM | 16 KB |
| EEPROM | 4 KB |
| Max Clock Frequency | 20 MHz |
| Supply Voltage Range | 1.8 V to 5.5 V |
| GPIO Count | 32 general purpose I/O lines |
| ADC | 8-channel 10-bit |
| USART Count | 2 |
| Timer/Counters | 3 with compare modes and PWM |
| Serial Interfaces | 2x USART, TWI (I2C-compatible), SPI |
| Package | 40-PDIP (through-hole) |
| Mounting Type | Through Hole |
| Special Features | picoPower, Real Time Counter, Read-While-Write Flash |
| Instruction Set Throughput | Up to 1 MIPS per MHz |
| Working Registers | 32 general purpose |
| Lifecycle Status | Active |
ATMEGA1284P-PU Pin Configuration
| Pin 1 | VCC β Digital supply voltage (1.8 V to 5.5 V) |
| Pin 2 | PB0 (XCK0/T0) β Port B bit 0; USART0 external clock / Timer0 external clock |
| Pin 3 | PB1 (T1) β Port B bit 1; Timer1 external clock input |
| Pin 4 | PB2 (AIN0/INT2) β Port B bit 2; analog comparator positive input / external interrupt 2 |
| Pin 5 | PB3 (AIN1/OC0A) β Port B bit 3; analog comparator negative input / Timer0 PWM output A |
| Pin 6 | PB4 (SS/OC1A) β Port B bit 4; SPI slave select / Timer1 PWM output A |
| Pin 7 | PB5 (MOSI/OC1B) β Port B bit 5; SPI master output / Timer1 PWM output B |
| Pin 8 | PB6 (MISO/OC1C) β Port B bit 6; SPI master input / Timer1 PWM output C |
| Pin 9 | PB7 (SCK/OC2A) β Port B bit 7; SPI clock / Timer2 PWM output A |
| Pin 10 | RESET β Reset input, active low; programming pin |
| Pin 11 | PD0 (RXD0) β Port D bit 0; USART0 receive |
| Pin 12 | PD1 (TXD0) β Port D bit 1; USART0 transmit |
| Pin 13 | PD2 (RXD1/INT0) β Port D bit 2; USART1 receive / external interrupt 0 |
| Pin 14 | PD3 (TXD1/INT1) β Port D bit 3; USART1 transmit / external interrupt 1 |
| Pin 15 | PD4 (XCK1/TOSC1) β Port D bit 4; USART1 external clock / RTC oscillator input |
| Pin 16 | PD5 (TOSC2/OC0B) β Port D bit 5; RTC oscillator output / Timer0 PWM output B |
| Pin 17 | PD6 (ICP1) β Port D bit 6; Timer1 input capture |
| Pin 18 | PD7 (OC2B/ICP2) β Port D bit 7; Timer2 PWM output B / Timer2 input capture |
| Pin 19 | PC0 (SCL) β Port C bit 0; TWI clock line |
| Pin 20 | PC1 (SDA) β Port C bit 1; TWI data line |
| Pin 21 | PC2 (TCK) β Port C bit 2; JTAG test clock |
| Pin 22 | PC3 (TMS) β Port C bit 3; JTAG test mode select |
| Pin 23 | PC4 (TDO) β Port C bit 4; JTAG test data output |
| Pin 24 | PC5 (TDI) β Port C bit 5; JTAG test data input |
| Pin 25 | PC6 (TOSC1) β Port C bit 6; Timer oscillator input (alternate RTC crystal pin) |
| Pin 26 | PC7 (TOSC2) β Port C bit 7; Timer oscillator output |
| Pin 27 | AVCC β Analog supply voltage for ADC and Port A |
| Pin 28 | GND β Ground |
| Pin 29 | AREF β Analog reference voltage for ADC |
| Pin 30 | PA7 (ADC7) β Port A bit 7; ADC channel 7 |
| Pin 31 | PA6 (ADC6) β Port A bit 6; ADC channel 6 |
| Pin 32 | PA5 (ADC5) β Port A bit 5; ADC channel 5 |
| Pin 33 | PA4 (ADC4) β Port A bit 4; ADC channel 4 |
| Pin 34 | PA3 (ADC3) β Port A bit 3; ADC channel 3 |
| Pin 35 | PA2 (ADC2) β Port A bit 2; ADC channel 2 |
| Pin 36 | PA1 (ADC1) β Port A bit 1; ADC channel 1 |
| Pin 37 | PA0 (ADC0) β Port A bit 0; ADC channel 0 |
| Pin 38 | XTAL2 β Main crystal oscillator output |
| Pin 39 | XTAL1 β Main crystal oscillator input / external clock input |
| Pin 40 | VCC β Digital supply voltage (second VCC pin) |
Typical Applications
ATMEGA1284P-PU is suitable for 6 applications: 3D Printer Controller Boards, Arduino-Compatible Hobbyist and Educational Builds, Legacy Industrial Equipment Repair and Retrofit, Battery-Powered Data Loggers, Dual-Serial Communication Gateways, Motor Control and PWM Systems.
3D Printer Controller Boards
The ATMEGA1284P-PU is the defining MCU of RepRap Sanguinololu-class 3D printer controller boards. Its 128 KB ISP Flash holds full Marlin or Sprinter firmware including acceleration planning tables, and its 16 KB SRAM maintains deeper step-planning buffers than 2 KB ATmega328 boards, directly improving print quality on curved surfaces. The dual USART can drive a host serial link and a second device such as a Panelolu display. The 40-pin PDIP package is socketed on these boards, allowing a failed MCU to be replaced with pliers and an ISP reflash rather than hot-air rework. Clocking at 16-20 MHz from a crystal, it coordinates stepper interrupts, thermistor ADC readings via the 10-bit ADC, and SD-card SPI traffic concurrently.
Recommended
Arduino-Compatible Hobbyist and Educational Builds
Through the MCUdude MightyCore board package, the ATMEGA1284P-PU integrates cleanly with the Arduino IDE, giving makers 128 KB Flash for large sketches and 16 KB SRAM for FAT16/FAT32 filesystem buffers, LCD frame buffers, or Ethernet stacks that overflow smaller ATmegas. The DIP-40 package drops into breadboards and soldered prototyping boards without adapters, and the 1.8 V to 5.5 V supply range tolerates Li-ion direct powering in low-clock modes. The 8-channel 10-bit ADC reads multiple sensors simultaneously, while dual USARTs let beginners debug over one serial port while communicating with a GPS or Bluetooth module on the other. Throughput near 1 MIPS per MHz keeps timing-critical bit-banged protocols feasible at modest clock speeds.
Recommended
Legacy Industrial Equipment Repair and Retrofit
The through-hole 40-pin PDIP package makes the ATMEGA1284P-PU a preferred MCU for repairing and retrofitting legacy industrial controllers where surface-mount rework is impractical. Its 128 KB Flash can absorb expanded firmware with new protocol stacks (Modbus RTU over one USART, field display on the other), and 16 KB SRAM supports historian-style logging into the 4 KB EEPROM. picoPower sleep modes suit intermittently powered dataloggers, while the 5.5 V maximum supply maps directly onto legacy 5 V TTL-era boards without level shifting. Socketed DIP replacement minimizes downtime: a pre-programmed spare ATMEGA1284P-PU can restore a machine in minutes, which is why maintenance shops stock this part alongside classic ATmega32 and ATmega8515 spares.
Recommended
Battery-Powered Data Loggers
With picoPower technology, the ATMEGA1284P-PU achieves very low sleep current while retaining its 32 KB-class RAM headroom for buffering thousands of ADC samples before a write burst. The 1.8 V minimum supply permits single-cell NiMH or two-cell alkaline operation with a 32.768 kHz crystal on the real-time counter keeping time independently of the main clock. The 8-channel 10-bit ADC digitizes multi-sensor arrays (temperature, humidity, pressure) while the 128 KB Flash stores calibration tables and data-compression code. Designers typically sleep in power-down mode, wake on timer or external interrupt, sample, and buffer in the 16 KB SRAM, achieving multi-year operation from primary cells when duty-cycled below 1 percent.
Recommended
Dual-Serial Communication Gateways
The two independent USARTs of the ATMEGA1284P-PU make it a natural protocol converter: one port faces a machine (RS-485 via a transceiver), the other faces a host PC or cellular modem. With 128 KB Flash, full protocol stacks for Modbus, DMX, or custom telemetry coexist with a bootloader supporting field firmware updates over the serial link using Read-While-Write Flash. The 16 KB SRAM buffers message bursts so the gateway tolerates upstream latency without dropping frames. Operating from a 14.7456 MHz or 18.432 MHz crystal yields exact standard baud rates with zero error, and the byte-oriented TWI bus adds local configuration EEPROM or display connectivity on the same two-wire pair.
Recommended
Motor Control and PWM Systems
Three flexible timer/counters with compare modes and PWM outputs let the ATMEGA1284P-PU drive multi-channel motor or LED systems from a single through-hole MCU. The 8-channel 10-bit ADC reads potentiometer commands and current-sense shunts, closing the control loop in firmware, while hardware PWM on OC0A/OC0B/OC1A/OC1B/OC2A/OC2B pins delivers glitch-free outputs independent of code jitter. 128 KB Flash accommodates field-oriented or PID control math plus HMI menus, and 16 KB SRAM holds trajectory setpoint tables. In RC, robotics, and DC-motor bench supplies, the DIP-40 package enables quick socket-level experimentation, and the 5 V rail interfaces directly to standard H-bridge driver inputs without level shifting.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA1284P-PU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA644P-PU | ATMEGA644A-PU | ATMEGA324P-PU | ATMEGA324PA-PU |
|---|---|---|---|---|---|
| Package | 40-PDIP (through-hole) | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 64 KB | 64 KB | 32 KB | 32 KB |
| SRAM | 16 KB | 16 KB | 4 KB | 2 KB | 2 KB |
| EEPROM | 4 KB | 4 KB | 2 KB | 1 KB | 1 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| USART Count | 2 | 2 | 1 | 2 | 2 |
| Supply Voltage Range | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
Key Differentiators
- Largest Flash and SRAM in the DIP-40 AVR family (vs ATMEGA644P-PU)
- Dual independent USARTs (vs ATMEGA644A-PU)
- picoPower low-power operation with RTC (vs ATMEGA324P-PU)
Design Notes
Decouple both VCC pins (1 and 40) and AVCC (pin 27) with 100 nF ceramic capacitors placed within 10 mm of each pin, plus a 10 uF bulk capacitor near the IC. AVCC must be connected to VCC even if the ADC is unused; floating AVCC is a common cause of ADC noise and port-A malfunctions on ATmega parts. At 20 MHz, use a 5 V supply per the datasheet frequency-voltage speed-grade table - the part will not reliably run at 20 MHz below 4.5 V.
For DIP-40 prototyping boards, route RESET (pin 10) with a 10 kOhm pull-up to VCC and bring it to an ISP header for in-system programming. Tie AREF (pin 29) to ground through 100 nF when using VCC/AVCC as the ADC reference, or decouple the external reference; never leave AREF floating. If using the real-time counter with a 32.768 kHz crystal, keep TOSC1/TOSC2 (pins 15/16 or 25/26) traces short and away from PWM carry to avoid oscillator startup failure.
Fuse bits are the most common source of ATMEGA1284P-PU field failures: an incorrect CKDIV8 or clock-source fuse can render a board apparently dead. Verify fuses with an ISP programmer before concluding hardware damage. JTAG is enabled by default on port C (pins 21-24); PC2-PC5 will not work as GPIO until JTAGEN is disabled via fuse. Also, Flash bootloader sections are protected by lock bits after ISP programming - clear lock bits before attempting to reflash.
Compliance Information
RoHS status per distributor listings (DigiKey/LCSC). REACH and conflict-minerals declarations should be confirmed via Microchip's product compliance portal.
