Microchip Technology ATMEGA256RFR2-ZF

Overview

ATMEGA256RFR2-ZF from Microchip Technology (formerly Atmel) is an 8-bit AVR microcontroller integrated with a 2.4 GHz IEEE 802.15.4/ZigBee transceiver in a single QFN-64 package. It delivers 256 KB Flash, 32 KB SRAM, 8 KB EEPROM, -100 dBm RX sensitivity, and up to +3.5 dBm TX output power. It targets low-power wireless sensor networks and mesh routers requiring concurrent MCU execution and robust RF communication.

For engineers reviewing the ATMEGA256RFR2-ZF datasheet, ATMEGA256RFR2-ZF pinout, ATMEGA256RFR2-ZF application, or ATMEGA256RFR2-ZF equivalent, key selection criteria include integrated MAC hardware acceleration, 38 programmable I/O lines, 16 MHz CPU operation at 1.8–3.6 V, deep-sleep current <700 nA, and dual crystal support (16 MHz + 32.768 kHz).

Technical Context

The ATMEGA256RFR2-ZF combines an enhanced RISC AVR core-executing 135 instructions in single cycles, delivering 16 MIPS at 16 MHz-with a fully integrated 2.4 GHz transceiver featuring fractional-N PLL, DSSS modulation, hardware CRC-16, auto-acknowledge, and 32-bit IEEE 802.15.4 symbol counter. Its architecture eliminates external memory interface needs via 32 KB on-chip SRAM.

Power management includes six software-selectable sleep modes, with Deep Sleep consuming <700 nA while retaining watchdog timer, MAC symbol counter, and 32.768 kHz oscillator functionality. The transceiver supports data rates of 250 kb/s to 2 Mb/s and integrates AES encryption and true random number generation for secure ZigBee Pro stack implementation.

Key Specifications

Pinout & Package

The ATMEGA256RFR2-ZF is housed in a 64-pad QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad internally connected to AVSS. Soldering the center pad ensures mechanical stability and optimal thermal dissipation; leaving it unconnected risks board detachment.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2.4 GHz wireless MCU applications.

Compared with ATMEGA256RFR2-ZF, ATMEGA128RFR2-ZUR offers identical RF capability at lower memory cost but limits complex mesh routing scalability, while CC2652R1F provides broader protocol flexibility and higher processing headroom at the expense of AVR ecosystem continuity and discrete balun integration effort.

Availability

ATMEGA256RFR2-ZF is available at Aetrix Electronics and suitable for smart energy hubs, industrial wireless sensor networks, and ZigBee Pro coordinator nodes requiring stable component supply across extended production lifecycles.

Supply support for ATMEGA256RFR2-ZF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology acquired Atmel in 2016 and maintains full support for the AVR wireless MCU portfolio, including documentation, development tools, and long-term supply commitments.

The ATMEGA256RFR2-ZF belongs to the Atmel RFR2 family designed specifically for ultra-low-power, standards-compliant ZigBee and IEEE 802.15.4 mesh networking-emphasizing integrated RF/MCU co-design, hardware MAC acceleration, and battery-operated longevity.

FAQ

What is the operating voltage range for ATMEGA256RFR2-ZF?

The ATMEGA256RFR2-ZF operates from 1.8 V to 3.6 V across its DEVDD and EVDD supply pins. Internal voltage regulators generate stable DVDD and AVDD rails, allowing direct connection to single Li-ion or two-cell alkaline sources without external LDOs. This range supports both high-performance 16 MHz operation and ultra-low-power sleep modes down to 1.8 V.

Does ATMEGA256RFR2-ZF require external crystals?

Yes, ATMEGA256RFR2-ZF requires two external crystals: a 16 MHz crystal on XTAL1/XTAL2 for the RF transceiver PLL and a 32.768 kHz crystal on TOSC1/TOSC2 for the asynchronous timer and MAC symbol counter. Both crystals must be placed close to their respective pins with minimal trace length and shielding from digital noise to ensure frequency stability and low-jitter timing.

How many I/O pins does ATMEGA256RFR2-ZF provide?

ATMEGA256RFR2-ZF provides 38 programmable I/O lines across Ports B, D, E, F, and G. These include dedicated RF control signals (DIG1/DIG2), serial interfaces (2x USART, SPI, TWI), ADC inputs (8-channel, 10-bit), and PWM outputs. Port A and Port C are not physically implemented, preserving pin count while optimizing die size and power efficiency.

What RF data rates does ATMEGA256RFR2-ZF support?

ATMEGA256RFR2-ZF supports IEEE 802.15.4-compliant data rates of 250 kb/s, 500 kb/s, 1 Mb/s, and 2 Mb/s. The transceiver uses DSSS modulation with hardware spreading and despreading, and all rates maintain the same -100 dBm receiver sensitivity and +3.5 dBm maximum transmit power. Rate selection is software-configurable per packet to balance range, throughput, and interference resilience.

Is ATMEGA256RFR2-ZF compatible with existing ATmega2561 code?

ATMEGA256RFR2-ZF maintains register-level compatibility with ATmega2561 for most peripherals (Timers, USART, SPI, ADC), but excludes Port A and Port C and their associated external memory interface. Software using those ports or high-voltage programming (BS2) must be adapted-TST pin replaces BS2 for programming, and CLKI replaces external clock input. Migration paths are documented in Atmel Application Note AVR1017.