Arduino Nano R4 vs Nano Every: RA4M1 vs ATmega4809 Compared

The Arduino Nano R4 and Arduino Nano Every look similar, fit the same Nano-style footprint and both operate in a 5 V logic environment.

Architecturally, however, they are very different boards.

Nano Every is a modernised 8-bit AVR platform based on the ATmega4809. Nano R4 moves the Nano family to a 32-bit Renesas RA4M1 Arm Cortex-M4 with much more memory and several peripherals that simply do not exist on Nano Every.

The short version is:

Both remain useful. The right choice depends less on physical form factor and more on whether you need AVR compatibility or modern peripherals.

Quick Comparison

Feature	Nano Every	Nano R4
Main MCU	ATmega4809	Renesas RA4M1
CPU	8-bit AVR	32-bit Arm Cortex-M4 + FPU
Clock	Up to 20 MHz silicon; current Arduino core uses 16 MHz	48 MHz
Logic voltage	5 V	5 V
Flash	48 kB	256 kB
SRAM	6 kB	32 kB
Non-volatile data	256 B EEPROM	8 kB data/EEPROM-style memory
ADC	10 bit	Up to 14 bit
True DAC	No	12 bit on A0
Op-amp	No integrated application op-amp	Yes, A1/A2/A3
CAN	No	Yes, external transceiver required
RTC	Real-time counter peripheral	Calendar RTC with backup domain
USB	SAMD11 bridge	Native RA4M1 USB-C
USB HID from main sketch	Not native to ATmega4809	Yes
I²C	Main bus on A4/A5	Main A4/A5 + separate 3.3 V Qwiic bus
GPIO current	20 mA recommended, 40 mA maximum per pin	8 mA maximum per GPIO
VIN	7-21 V	6-21 V
USB connector	Micro-USB	USB-C

The Biggest Difference: AVR vs Arm Cortex-M4

Nano Every uses the ATmega4809, part of Microchip’s megaAVR 0-series.

It is still fundamentally an AVR architecture:

Nano R4 instead uses:

This affects far more than benchmark speed.

Code that performs:

• floating-point calculations;
• large buffers;
• signal processing;
• complex communication stacks;
• USB functions;
• larger state machines;

has much more headroom on Nano R4.

Clock Speed: 20 MHz vs 48 MHz Is More Complicated Than It Looks

Arduino’s Nano Every product page describes the ATmega4809 as running at up to 20 MHz.

However, the current official Arduino megaAVR core defines:

for Nano Every.

So in a normal current Arduino installation, your Nano Every sketch should be treated as a 16 MHz Arduino environment unless you deliberately change the core configuration.

Nano R4 runs its RA4M1 at:

and the difference is larger than raw clock frequency because Cortex-M4 is a 32-bit processor with hardware floating point.

Memory Difference

Memory	Nano Every	Nano R4
Flash	48 kB	256 kB
SRAM	6 kB	32 kB
Non-volatile data	256 B EEPROM	8 kB

Nano R4 therefore provides roughly:

That changes what kinds of applications are comfortable to write.

On Nano Every, a few large arrays, JSON buffers or display framebuffers can consume a meaningful percentage of the 6 kB SRAM.

On Nano R4, 32 kB is still not huge by ESP32 standards, but it gives much more room for:

• protocol buffers;
• larger lookup tables;
• sensor logging;
• USB stacks;
• larger libraries.

Both Boards Are 5 V

This is the major reason Nano R4 is attractive to Nano Every users.

Both boards work in a 5 V GPIO environment.

That makes migration easier for:

• 5 V LCD modules;
• legacy sensors;
• relay boards;
• 74HC logic at 5 V;
• existing Nano carrier boards.

You do not have to redesign every interface around 3.3 V logic as you would when moving to Nano ESP32, Nano Matter or Nano 33 BLE.

But the GPIO Current Limit Changes Significantly

Nano Every’s official pinout recommends:

Nano R4’s current datasheet specifies:

This is a very important migration difference.

A circuit that directly drives a relatively bright LED from Nano Every may need a different resistor or external transistor when moved to Nano R4.

In general, treat both boards as logic controllers rather than power drivers.

Analog Input: Nano R4 Is Much More Capable

Nano Every uses the ATmega4809 ADC and standard Arduino operation is essentially a 10-bit analog workflow.

Nano R4 supports:

so:

Use:

on Nano R4.

Resolution Is Not the Same as Accuracy

Nano R4’s 14-bit conversion gives finer quantisation, but actual measurement quality still depends on:

• reference accuracy;
• source impedance;
• noise;
• layout;
• grounding;
• ADC gain and offset errors.

Do not assume Nano R4 becomes a laboratory-grade 14-bit instrument simply because the API returns 14-bit values.

Nano R4 Has a True 12-Bit DAC

Nano Every has no true voltage DAC.

Nano R4 provides:

Example:

This generates an actual analog voltage rather than a PWM waveform.

That is useful for:

• control voltages;
• simple waveform generation;
• audio experiments;
• analog setpoints.

Nano R4 Also Adds an Op-Amp

The RA4M1 integrated operational amplifier is exposed as:

Nano Every does not expose an equivalent integrated signal-conditioning block.

This can reduce external component count for simple analog front ends.

CAN: Nano R4 Wins Easily

Nano R4 has a built-in classic CAN controller.

The board mapping is:

You still need an external CAN transceiver between those pins and:

Nano Every has no comparable built-in CAN peripheral.

For vehicle, industrial or distributed-controller projects, this is one of the strongest reasons to choose Nano R4.

RTC: These Boards Do Not Mean the Same Thing by “Real Time”

ATmega4809 contains a 16-bit Real-Time Counter peripheral.

That is useful for:

• low-power timing;
• periodic interrupts;
• long-duration counters;
• wake-up timing.

It is not the same kind of calendar/time-of-day subsystem as the RA4M1 RTC.

Nano R4 provides a real RTC capable of:

• date;
• time;
• calendar operation;
• alarms;
• backup-domain operation.

So for timestamps and clock/calendar applications, Nano R4 is substantially more convenient.

USB Architecture

This is another fundamental difference.

Nano Every

The main ATmega4809 does not directly own the USB connection.

The SAMD11 bridge handles:

• programming;
• USB serial;
• UPDI interface.

Nano R4

The application MCU directly owns USB.

Why Native USB Matters

Nano R4 can implement device functions such as:

• keyboard;
• mouse;
• USB HID;
• USB serial;
• custom USB-device applications supported by the core.

Nano Every’s standard main sketch does not have native USB in the same way because USB terminates in the SAMD11 bridge.

USB Connector Difference

Nano Every uses Micro-USB.

Nano R4 uses USB-C.

This does not change embedded functionality by itself, but USB-C is more convenient for modern cables and improves mechanical usability.

I²C: Nano R4 Adds a Second Bus

Both boards provide the familiar main Nano I²C bus:

Nano R4 additionally includes a dedicated Qwiic connector.

The Qwiic bus:

• is separate from A4/A5;
• operates at 3.3 V;
• uses Wire1 in the current core;
• can host devices with an address that duplicates a device on the main bus.

This makes Nano R4 much more flexible for mixed 5 V/3.3 V sensor projects.

SPI and UART Stay Familiar

Both boards preserve the normal Nano-style external buses:

This helps high-level Arduino libraries migrate between the two boards.

PWM: Similar Concept, Different Timer Hardware

Nano Every’s current standard PWM mapping is:

Nano R4 provides six official PWM outputs:

The similarity in pin names hides very different underlying timer architectures.

Nano Every Timer Architecture

ATmega4809 uses:

• TCA;
• TCB;
• RTC;
• event-system routing.

This already differs substantially from classic ATmega328P timers.

Nano R4 Timer Architecture

RA4M1 uses Renesas timer peripherals such as GPT hardware and a completely different register model.

So code that manually configures Nano Every timers will need a rewrite on Nano R4.

Library Compatibility

Libraries fall into three broad groups.

1. High-Level Arduino Libraries

Libraries using APIs such as:

have the best chance of working on both boards.

2. AVR-Specific Libraries

Libraries using:

will need review or rewriting for Nano R4.

3. Architecture-Specific Libraries

Some libraries provide separate backends for:

• AVR;
• Renesas;
• SAMD;
• ESP32;

Check the current library’s supported architectures before assuming a Nano Every project will compile unchanged on Nano R4.

Flash/PROGMEM Assumptions Change

AVR applications often use PROGMEM aggressively because RAM is tiny and the AVR memory model separates Flash and data memory.

On a 32-bit Arm board like Nano R4, memory handling is different.

Code may still compile through compatibility macros, but low-level pointer assumptions and Flash-access helpers should be reviewed.

Floating Point

Nano R4’s Cortex-M4 includes hardware floating-point support.

Nano Every performs floating-point arithmetic in software on the AVR CPU.

Applications involving:

• filters;
• PID calculations;
• sensor calibration;
• trigonometry;
• signal processing;

can therefore benefit significantly from Nano R4.

Interrupts

Nano Every improves substantially over classic Nano because ATmega4809 can route interrupts from many GPIO.

Nano R4 also provides flexible external interrupt support.

For portable code, continue using:

rather than relying on device-specific registers.

Power Input

Board	VIN
Nano Every	7-21 V
Nano R4	6-21 V

Both use onboard switching regulation rather than relying on the old linear-regulator approach found on many classic Arduino boards.

This gives them useful tolerance for automotive-style 12 V supplies, although electrical noise, surges and load transients still require proper protection in real installations.

Physical Compatibility Does Not Guarantee Electrical Compatibility

Both use the Nano form factor, but do not assume a carrier designed for Nano Every is automatically perfect for Nano R4.

Check:

• pin current requirements;
• A6/A7 behaviour;
• BOOT/reset-related positions;
• analog voltage expectations;
• USB connector clearance;
• whether the carrier expects AVR-specific behaviour.

Which Board Is Easier for an Existing Nano Every Project?

If the project uses only:

• digital I/O;
• Wire;
• SPI;
• Serial1;
• analogRead;
• standard Arduino libraries;

then moving to Nano R4 can be relatively straightforward.

If the project uses:

• direct timer registers;
• AVR-specific ISR code;
• low-level port manipulation;
• ATmega4809-specific event system;
• memory tricks based on AVR;

then the migration is a real port rather than a board swap.

When Nano Every Is Still the Better Choice

Nano Every remains sensible when:

• the existing codebase is AVR-specific;
• 48 kB Flash and 6 kB RAM are enough;
• you only need simple digital/analog control;
• you want a small 5 V board without advanced peripherals;
• cost and simplicity matter more than performance.

When Nano R4 Is Clearly Better

Choose Nano R4 when you need:

• more Flash and RAM;
• hardware floating point;
• higher-resolution ADC;
• true analog output;
• CAN;
• calendar RTC;
• native USB/HID;
• USB-C;
• an integrated op-amp;
• a second 3.3 V Qwiic I²C bus.

Nano Every vs Nano R4 for Automotive or Industrial Control

Nano R4 has the stronger hardware base because it includes:

Neither development board should automatically be treated as an automotive-qualified or industrially hardened controller, but Nano R4 requires fewer external building blocks for a prototype.

Nano Every vs Nano R4 for Sensor Nodes

If the sensor node is simple:

Nano Every has enough capability.

If the design needs:

• higher-resolution analog acquisition;
• multiple I²C buses;
• analog output;
• RTC timestamps;
• CAN networking;

Nano R4 is much more capable.

Quick Migration Checklist

1. Replace any Micro-USB mechanical assumptions with USB-C clearance.
2. Check every directly driven load against Nano R4’s 8 mA GPIO limit.
3. Search the codebase for AVR headers and direct register access.
4. Review timer/PWM code.
5. Keep A4/A5 as the main I²C bus unless intentionally migrating sensors to Qwiic/Wire1.
6. Use Serial for native USB and Serial1 for D0/D1.
7. Re-test ADC scaling if increasing resolution.
8. Do not assume EEPROM size or API behaviour is identical.
9. Verify library support for the Renesas architecture.
10. Re-test startup, reset and bootloader behaviour on the finished carrier.

Quick Reference

Final Thoughts

Nano R4 is not simply a faster Nano Every.

It changes the processor architecture, USB model, analog subsystem, timer hardware, peripheral set and GPIO-current limits.

Nano Every still makes sense as a small, inexpensive 5 V AVR board where existing code and simplicity matter.

Nano R4 is the stronger choice for new 5 V embedded designs that need more than basic I/O.

The key migration question is:

For detailed pin mappings, see our Nano Every pinout guide and Nano R4 pinout guide.