Flux Blog

News, resources, and company updates

AI Auto-Layout Winter Update

AI Auto Layout’s Winter Update delivers cleaner, more human-like routing with faster, more reliable results. It handles most of the routing workload so you can focus on the critical parts of your PCB design.

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November 20, 2025
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Flux + GPT-5 (Beta)

Flux + GPT-5 (Beta)

Open Flux now, switch Copilot to “Next-gen” and see how it handles your next design challenge. The sooner you try it, the more your feedback can shape the next leap in AI-powered hardware design.

In the right scenarios, it’s already delivering sharper reasoning, smarter reviews, and more accurate design decisions than anything we’ve shipped before. We wanted to get it into your hands immediately so you can explore what’s possible alongside us. It’s early, it’s raw, and we want you to push it. Break it. Tell us where it shines.

Try It Now

You can start using it right away. Open any project in Flux and launch Copilot. Click the model dropdown at the top of the chat panel, select “Next-gen” and then give it a real challenge. Some great starter prompts to see its strengths include:

“Perform a top-to-bottom schematic review for correctness, completeness, and robustness. Assess power, clocks/resets, signal interfaces, analog paths, protection, and passive choices.”
“Replace all low-stock parts with alternatives that meet the same constraints.”

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What’s New and Better

The upgrade isn’t just that GPT-5 is a newer model. It brings a different caliber of intelligence to Copilot:

  • Stronger reasoning and planning for complex, multi-step problems.
  • More accurate part and constraint decisions, often with clearer explanations.
  • Sharper design reviews that catch subtle issues and propose fixes.
  • Richer, more verbose answers that lay out assumptions, tradeoffs, and edge cases.

These improvements land harder in Flux because Copilot already has deep, live context on your design—down to parts, pins, nets, properties, constraints, and stackups—so reinforcement models and LLMs can work side-by-side from the canvas up to system architecture. And because Flux is built for agentic workflows—stepwise actions, constraint-aware edits, and iterative design loops right where you work—GPT-5 isn’t starting from scratch; it applies improved reasoning directly to your schematic or layout. Layered on top is a knowledge base of industry best practices and embedded design/process checks, so your AI partner starts from seasoned experience and turns that context into answers that are immediately relevant and actionable.

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Early Win from the Weekend

In just 48 hours of testing, we saw moments that made us stop and say, “This is new.”

Design a low-noise microphone preamplifier for an electret condenser mic feeding a 24-bit ADC. You must calculate the bias network, gain-setting resistors, coupling capacitors, input high-pass cutoff, output anti-aliasing RC, and decoupling layout. Follow the op-amp and microphone capsule datasheets, ADC input requirements, and industry best practices. It will be integrated into a design. Supply: 3.3V analog rail. Mic bias: 2.0 V through resistor, current ~0.5 mA. Target gain: 20 dB to 40 dB switchable. Bandwidth: 20 Hz to 20 kHz. Input noise target: as low as practical. Include pop-suppression considerations and star-grounding strategy.

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In this case Flux took a plain-English prompt and produced a full low-noise mic preamp to a 24-bit ADC—calculating the right bias, gain, and filter values, choosing real parts, then placing and wiring the entire block with decoupling, VCM bias, and star-ground best practices. It even audited itself (fixed missed ties, made gain legs switchable). The result is a ready-to-review schematic 80% away from layout built end-to-end—complex, competent, and fast.

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Getting the most from “Nex Gen” model in Flux

  • Read the whole answer. The “Next Gen” model is verbose on purpose—the assumptions, edge cases, and self-checks are where the value lives.
  • Front-load context. In your first message, share goals; rails & loads; key interfaces (e.g., USB-C: CC1/CC2, D+/D−, SBU); constraints (cost/size/EMI); and manufacturing rules of thumb. Keep answering follow-ups to deepen the design.
  • Scope tightly. When wiring schematics, tackle one rail, one bus, or one block at a time.
  • Plan before you act. Validate the change plan against requirements before applying edits—changing the plan is cheaper than undoing work.

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What’s Next

Right now GPT-5 powers Copilot’s chat, but this is just the beginning. We’re already working on:

  • Tighter loops between chat and in-editor actions.
  • More constraint-aware placement and routing.
  • Datasheet-to-design transformations in minutes.
  • Smarter, in-context automated fixes.

Open Flux now, switch Copilot to “Next-gen” and see how it handles your next design challenge. The sooner you try it, the more your feedback can shape the next leap in AI-powered hardware design.

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August 11, 2025
AI Assistance Inside Every ECAD Tools

AI Assistance Inside Every ECAD Tools

This blog compares AI capabilities across Flux.ai, Altium, KiCad, and EasyEDA to answer engineers’ highest-intent questions about modern PCB design. It explains why Flux.ai currently delivers the strongest end-to-end AI workflow in the ECAD space.

The reality in 2025 is this:

"AI isn’t replacing electrical engineers but it is starting to feel like a useful teammate."

Not a perfect one, not one you fully trust yet, but one that can save time on the tedious parts, catch mistakes earlier, and help you iterate from idea to prototype faster.

Across the industry, adoption is uneven. Traditional desktop ECAD tools like Altium and KiCad still treat AI as an optional plugin or an external script-driven add-on. Meanwhile, newer cloud-native platforms, most notably Flux.ai, have begun integrating AI directly into the design loop: reading datasheets, proposing schematics, suggesting parts, routing boards, and even explaining the reasoning behind design choices.

But engineers are right to be cautious. PCB design isn’t text prediction, it’s physics, constraints, standards, and consequences. A misrouted high-speed lane, wrong MOSFET footprint, or power sequencing mistake isn’t a typo; it’s a lost week, lost money, and sometimes a lost product.

This article focuses on the questions hardware engineers really ask, the practical, high-stakes ones that determine whether AI can actually save time or just create new risks. Each section breaks down how modern ECAD tools like Flux, Altium, KiCad, and EasyEDA — handle these real-world workflows.

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Is there an AI that can plan a PCB design from a product spec and ask clarifying questions?

Most engineers start with vague product requirements — “battery-powered sensor,” “USB-C powered device,” “motor controller” but translating that into electrical design constraints is slow and error-prone. An AI that can read a spec and ask the same clarifying questions a junior engineer would (power budget, interfaces, sensors, EMI constraints) reduces iteration time and catches missing requirements early.

Short answer: Flux is the only ECAD that does this natively today.

Flux.ai

Flux can interpret natural-language specs, ask clarifying questions, propose block diagrams and functional structure then it generates a detailed plan. It behaves like a junior hardware engineer thinking out loud.

Try this prompt:

Design a sub-25 × 25 mm wearable PCB with Bluetooth, an accelerometer, and on-board battery charging.

It must include a BLE SoC (OTA-capable), a low-power accelerometer with interrupt/wake, power-path + charging for a 1-cell Li-ion/LiPo, and headers/pads for programming and test.

Power: 1-cell Li-ion/LiPo with on-board charger (5 V USB input) optimized for low quiescent current.”

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Altium

No native AI planning. External tools may help with ideation, but no clarifying questions.

KiCad

Completely manual. You are on your own.

EasyEDA

Has basic AI chat, but no requirements-driven design planning.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | Reads product spec | ✅ | ❌ | ❌ | ❌ | | Asks clarifying questions | ✅ | ❌ | ❌ | ❌ | | Generates design plan | ✅ | ❌ | ❌ | ❌ | | Conversational loop | ✅ | ❌ | ❌ | ❌ |

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Can an AI suggest parts, build schematic diagram, then route with my guidance?

In real workflows, engineers often spend hours picking components, checking footprints, wiring standard circuits, and placing obvious blocks like regulators, microcontrollers, and connectors. A capable AI that drafts these first passes while letting the engineer steer and refine, dramatically accelerates early design cycles and frees time for deep engineering decisions.

Flux.ai

Flux currently has the most advanced AI-assisted design flow:

  • AI part suggestions
  • Schematic and system block generation
  • Auto-routing called AI Auto-Layout
  • Iterative human-in-the-loop guidance

Altium

Altium can help with component data via Octopart, but AI doesn't generate schematics or placement.

KiCad

No AI, only scripting through third-part plugins

EasyEDA

Basic recommendations and cloud routing, but not AI-driven.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | AI part suggestions | ✅ | ✔️ (Octopart) | ❌ | ✔️ (limited) | | AI schematic generation | ✅ | ❌ | ❌ | ❌ | | AI-assisted routing | ✅ | ❌ | ❌ | ❌ | | Iterative guidance | ✅ | ❌ | ❌ | ❌ |

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How do I teach an ECAD AI my house rules and naming conventions once?

Hardware teams develop their own standards over years, naming conventions, preferred footprints, power-tree structures, and layout principles. Re-teaching those rules every time a new engineer joins or every time you start a new board is one of the biggest sources of avoidable friction in PCB workflows.

Flux.ai

Flux solves this with its Knowledge Base, which allows engineers to store reusable electrical engineering “knowledge chunks” the AI can reference during design. Unlike static templates, the Knowledge Base includes:

  • User-level rules (e.g., how you name nets, preferred library components, symbol conventions)
  • Project-level rules (e.g., specific stackups, chosen IC families, grounding strategy for this board)
  • Semantic triggers (“use when” cues) that automatically activate the right rule when the design context calls for it
  • EE-aware organization so the AI knows which rules relate to schematics, layout, stacks, or system architecture

Flux doesn’t just store these rules, it applies them automatically when generating schematics, naming nets or choosing footprints strategies. It’s the first ECAD tool where your internal engineering standards become a living and reusable knowledge system.

Altium, KiCad, EasyEDA

These tools rely on templates, scripts, or third-party plugins but none provide persistent, context-aware AI learning or automatic implementation of company standards.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | Learns naming conventions | ✅ | ❌ | ❌ | ❌ | | Remembers preferences | ✅ | ❌ | ❌ | ❌ | | Applies rules across projects | ✅ | ❌ | ❌ | ❌ | | Adapts imported schematics | ✅ | ❌ | ❌ | ❌ | | Semantic “use when” rule activation | ✅ | ❌ | ❌ | ❌ |

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AI that explains why it picked that component, does that exist?

Engineers need to trust routing, and part choices, especially when they affect signal integrity, EMI, power delivery, or thermal behavior. Having an AI that can justify decisions (“this cap is here to shorten loop inductance,” “this MOSFET variant reduces cost with identical performance”) closes the trust gap and makes AI-driven design actually usable in production workflows.

Flux.ai

One of the biggest differentiators: Flux gives clear natural-language reasoning.It explains why something routed, or chosen.

Other Tools

No explainable AI features exist.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | Explains part selection | ✅ | ❌ | ❌ | ❌ | | Datasheet-based reasoning | ✅ | ❌ | ❌ | ❌ |

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Best auto-router approaches for low-to-medium density boards in 2025

Most commercial products aren’t 12-layer high-speed monsters, they’re 2–4-layer sensor nodes, wearables, IoT modules, power converters, and mixed-signal control boards. For these designs, route quality depends far more on smart placement, clean topologies, and constraint-aware decision making than on raw high-density routing power. This is where the newest generation of AI-driven algorithms has begun outperforming classical routers.

Flux.ai

Flux’s AI Auto-Layout represents the most human-like routing behavior available in ECAD today. With Flux’s latest update, the system doesn’t simply push traces through a maze router, it imitates how real engineers reason about routing:

  • It considers circuit topology (power trees, high-current loops, analog/digital partitioning).
  • It routes connectors, regulators, microcontrollers, and passives in ways that minimize parasitics.
  • It routes with “human-style” patterns — short runs, logical flow, good return paths, and neat organization.
  • It optimizes trace paths iteratively rather than dumping a brute-forced solution.

For low-to-medium density boards (2–4 layers), Flux’ Auto-Layout produces results that closely resemble an experienced EE’s first-pass layout, not a mechanical maze-router output. It’s the first auto-layout system that actually looks designed, not auto generated.

Altium

Altium’s ActiveRoute remains one of the best deterministic routers on the market. It’s excellent when the designer put up so much time setting up constraints properly, but it still relies on classical algorithms rather than human-like reasoning.

KiCad

FreeRouting offers reasonable results for simpler boards, but it struggles with medium-density designs or anything requiring nuanced placement strategy.

EasyEDA

EasyEDA’s router is functional and fast for hobby-level projects, but lacks advanced constraint handling or professional-grade refinement.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | AI optimization of component groups | ✅ | ❌ | ❌ | ❌ | | Human-like trace patterns | ✅ | ❌ | ❌ | ❌ | | Classical constraint routing | ✅ | ✔️ | ✔️ (limited) | ❌ | | Quality on 2–4 layer boards | ⭐ Leader | ⭐ Strong | ⚠️ Mixed | ⚠️ Basic | | Best for low–medium density in 2025 | 🏆 Flux.ai | ⭐ Runner-up | ❌ | ❌ |

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Step-by-step: using AI to review my design for obvious mistakes

Even experienced engineers overlook missing pull-ups, incorrect footprints, swapped differential pairs, or bad return paths when moving fast. AI-driven review acts like a second pair of eyes that never gets tired, catching easy-to-miss issues before fabrication, when mistakes are still cheap.

Flux.ai

Flux runs a deep AI review:

  • Detects common EE mistakes
  • Explains issues
  • Suggests fixes

Other Tools

Altium, KiCad, and EasyEDA provide ERC/DRC — but no AI reasoning.

| Capability | Flux.ai | Altium | KiCad | EasyEDA | | :--- | :--- | :--- | :--- | :--- | | AI reasoning | ✅ | ❌ | ❌ | ❌ | | Detects EE mistakes | ✅ | ⚠️ Basic | ⚠️ Basic | ⚠️ Basic | | Suggests fixes | ✅ | ❌ | ❌ | ❌ | | Explains issues | ✅ | ✔️ | ❌ | ❌ |

Flux is redefining what modern ECAD looks like

Every other tool still treats AI as a bolt-on accessory, helpful around the edges but never involved in real engineering decisions. Flux.ai takes the opposite approach: AI is embedded in the workflow from the moment you describe your product idea to the moment you’re reviewing your final layout. It asks the right questions, explains its decisions, follows your internal rules, and eliminates entire categories of tedious work that engineers have accepted for years.

This isn’t “AI for PCB design someday.” It’s the first platform where AI becomes a capable design partner today.

If you’re serious about faster iteration, fewer mistakes, and a workflow that evolves with the future of hardware development, Flux.ai is the tool that sets the new standard, and the direction the rest of the industry will be trying to catch up to.

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November 21, 2025
Meet the Arduino Nano R4: Why Is This Tiny Upgrade So Big for Makers?

Meet the Arduino Nano R4: Why Is This Tiny Upgrade So Big for Makers?

Arduino Nano R4 packs UNO R4 performance into Nano size. Learn specs, standout features, and who should upgrade in this in-depth guide.

What Exactly is the Arduino Nano R4?

The Arduino Nano R4 is a significant upgrade to Arduino’s popular Nano line, powered by the Renesas RA4M1 microcontroller. Imagine taking the powerful brains of the Arduino UNO R4 and shrinking them into a tiny, versatile form. With a 48 MHz Arm Cortex-M4F core, 256 KB of flash storage, and integrated EEPROM, the Nano R4 provides remarkable performance in a miniature footprint.

Regardless of whether you're prototyping, building IoT projects, or designing space-conscious hardware, the Nano R4 is designed to streamline your workflow and empower your creativity.

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What's New in the Arduino Nano R4?

The Nano R4 offers  exciting new features, making it one of Arduino’s most attractive small boards ever released:

  • Enhanced Processing Power: 48 MHz Arm Cortex-M4F MCU (Renesas RA4M1).
  • Expanded Memory: 256 KB Flash, 32 KB SRAM, and 8 KB EEPROM.
  • Compact & Production-Friendly: Single-sided component placement and castellated headers for easy PCB integration.
  • Versatile Connectivity: USB-C, built-in 3.3V Qwiic I²C connector, additional 5V I²C compatibility, UART, SPI, PWM, DAC, and CAN bus support.
  • Real-Time Clock (RTC): An integrated RTC with battery backup capability for accurate timekeeping.
  • RGB LED Indicator: Onboard LED for debugging, feedback, or user-interface enhancements.

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Looking to Fast-Track Your Arduino Hardware Design?

Browse the shield templates below, each pre-aligned with headers, that let hardware engineers move from concept to working prototype in record time. Choose a template, customize it to your needs, and start building.

  1. Arduino MKR Wifi Template
  2. Arduino Nano 33 Template
  3. Arduino MKR Zero Template
  4. Arduino Nano RP2040 Template

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Can I run my UNO R4 Minima sketch on a Nano R4?

Arduino Nano R4 keeps the classic Nano pin layout, so headers, shields, and breadboard wiring stay the same. Yes, just remap the pin numbers to match the Nano R4 layout. The Nano breakout connectors pinout is shown below:

Analog (JP1)

| Pin | Function | Type | Description | | :--- | :--- | :--- | :--- | | 1 | D13 / SCK | Digital | Serial Clock | | 2 | +3V3 | Power Out | +3V3 Power Rail | | 3 | B0 / AREF | Analog | Analog Reference | | 4 | A0 | Analog | Analog input 0 / DAC | | 5 | A1 | Analog | Analog input 1 / OPAMP + | | 6 | A2 | Analog | Analog input 2 / OPAMP – | | 7 | A3 | Analog | Analog input 3 / OPAMP Out | | 8 | A4 | Analog | Analog input 4 / I²C Serial Data (SDA) | | 9 | A5 | Analog | Analog input 5 / I²C Serial Clock (SCL) | | 10 | A6 | Analog | Analog input 6 | | 11 | A7 | Analog | Analog input 7 | | 12 | 5V | Power | USB power (5 V) | | 13 | BOOT1 | Mode | Board Reset 1 | | 14 | GND | Power | Ground | | 15 | VIN | Power | Voltage Input |

Digital (JP2)

| Pin | Function | Type | Description | | :--- | :--- | :--- | :--- | | 15 | D12 / CIPO | Digital | Controller In Peripheral Out | | 14 | D11 / COPI | Digital | Controller Out Peripheral In / PWM | | 13 | D10 / CS | Digital | Chip Select / PWM | | 12 | D9 | Digital | Digital pin 9 / PWM | | 11 | D8 | Digital | Digital pin 8 | | 10 | D7 | Digital | Digital pin 7 | | 9 | D6 | Digital | Digital pin 6 / PWM | | 8 | D5 | Digital | Digital pin 5 / PWM / CAN (RX) | | 7 | D4 | Digital | Digital pin 4 / CAN (TX) | | 6 | D3 | Digital | Digital pin 3 / PWM | | 5 | D2 | Digital | Digital pin 2 | | 4 | GND | Power | Ground | | 3 | RST | Internal | Reset (features a button) | | 2 | D0 / RX | Digital | Digital pin 0 / Serial Receiver (RX) | | 1 | D1 / TX | Digital | Digital pin 1 / Serial Transmitter (TX) |

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Why Does the Nano R4 Matter to Makers?

Compact Size, Big Performance

Nano R4 packs high-end functionality previously reserved for larger Arduino boards into a sleek, ultra-compact form factor. This allows makers to design more sophisticated, compact IoT and wearable projects without compromising power or features.

Seamless Transition from UNO R4

Already using Arduino’s popular UNO R4 boards? The Nano R4 offers complete compatibility with UNO R4’s software ecosystem, meaning your existing libraries, sketches, and workflows transfer smoothly to your Nano-sized projects.

Production Ready & Cost-Effective

The castellated headers and single-sided components ensure easy and cost-effective manufacturing—perfect for makers looking to transition prototypes into commercial products quickly and affordably.

Improved Connectivity and Expansion

The integrated Qwiic connector and additional I²C lines allow effortless integration of sensors, displays, and other peripherals. Add the RTC and RGB LED, and you have a remarkably versatile board ready for endless applications.

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Who Is the Arduino Nano R4 Designed For?

The Nano R4 meets a variety of needs:

  • Hobbyists & Students: Easy-to-use and powerful enough to handle beginner and advanced projects alike.
  • Product Developers: Small, affordable, and production-ready for embedding into commercial hardware.
  • Educators: Compact form factor and compatibility with Arduino IDE make it ideal for teaching embedded systems, robotics, and IoT concepts.

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How Does Nano R4 Compare to Previous Arduino Boards?

Compared to older Nano models (Nano Every or Nano 33), the Nano R4 offers substantial performance and memory improvements:

| Feature | Arduino Nano R4 | Arduino Nano Every | Arduino Nano 33 IoT | | :=== | :=== | :=== | :=== | | Microcontroller | Renesas RA4M1 (32-bit) | ATmega4809 (8-bit) | SAMD21 Cortex-M0+ (32-bit) | | Clock Speed | 48 MHz | 20 MHz | 48 MHz | | Flash Memory | 256 KB | 48 KB | 256 KB | | SRAM | 32 KB | 6 KB | 32 KB | | EEPROM | 8 KB 256 bytes | None | | RTC | ✅ Integrated | ❌ Not integrated | ❌ Not integrated | | Connectivity | USB-C, I²C, UART, SPI, CAN | Micro USB, UART, SPI, I²C | Micro USB, Wi-Fi, Bluetooth | | Form Factor | Nano-sized, castellated PCB | Nano-sized | Nano-sized |

The Nano R4 brings many of the features previously only available in higher-end Arduino boards into a Nano-sized form factor.

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Why Should You Upgrade to the Arduino Nano R4?

If you're currently using older Nano boards or even an Arduino UNO, here are quick reasons to make the jump to Nano R4:

  • Power & Performance: Significant upgrade with faster processing and more memory.
  • Better Compatibility: Simplified transition from UNO-based projects.
  • Lower Cost & Easier Manufacturing: Perfect for small-scale production or commercial projects.
  • Versatile Applications: Suitable for IoT, robotics, wearables, automation, and more.
  • Future-Proof: Modern features like USB-C, RTC, and expanded connectivity mean longer-lasting project relevance.

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Where Can You Get the Arduino Nano R4?

The Arduino Nano R4 is available in two variations:

  • Without Headers: Ideal for embedding into custom PCB designs (around $12.10).
  • With Pre-soldered Headers: Ready for quick prototyping and breadboarding (around $13.30).

Both versions are available directly from Arduino's online store and major electronics distributors.

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Ready to Start Your Nano R4 Project?

Arduino’s Nano R4 sets a new standard for compact, powerful, and production-friendly microcontroller boards. Whether you’re prototyping the next big IoT device or scaling your prototype for production, the Nano R4 offers the power and flexibility you need.

Visit our Featured Projects page to discover innovative Arduino builds and spark inspiration for your next big idea.

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August 7, 2025
RP2350 A4 Stepping: Why Raspberry Pi Pico’s Latest Upgrade Changes Everything

RP2350 A4 Stepping: Why Raspberry Pi Pico’s Latest Upgrade Changes Everything

RP2350 A4 fixes GPIO bug, hardens security, adds 5 V tolerance and on-chip flash. See why every Pico project should migrate.

What Is the RP2350 A4 Stepping?

The RP2350 A4 stepping is the latest iteration of Raspberry Pi's powerful dual-core MCU, designed to correct significant hardware and security issues identified in earlier versions (particularly the A2 stepping). This update provides comprehensive improvements, delivering both enhanced security and optimized hardware performance, making it a must-have upgrade for serious developers and embedded systems designers alike.

If you're connecting the RP2350 to retro computing hardware, there's good news: after extensive testing, the RP2350 is now officially 5V tolerant!

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Can My Current Pico Projects Run on the New A4 Stepping?

Absolutely! Because A4 is a pin-compatible, drop-in replacement, your existing Pico designs work right away, often with nothing more than a rebuild on the latest SDK. Here are four examples you can migrate today:

  1. Pico Smart Automation Controller – A DIY home-automation hub that enables intelligent control for sensors, relays, and devices.
  2. Pico Macro Keyboard – A customizable USB HID keypad a.k.a macro pad built using the Raspberry Pi Pico 2.
  3. Avocaudio – Tiny Community Audio Board – A tinyML board designed for extensive audio data collection across various tinyML applications.
  4. Raspberry Pi Pico 2 Shield Template – A ready-made “shield” PCB that mirrors the exact footprint and pin order of the Pico 2, much like an Arduino shield.

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How Can I Tell If I Have the A2 or A4 Stepping?

You can identify the stepping version from the marking on the top surface of the chip, as illustrated below.

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Do Pinouts Change with the RP2350 A4 Stepping?

No, great news for hardware engineers! The pin configuration and layout of the RP2350 A4 stepping remain identical to earlier versions, making it a perfect drop-in replacement. You can upgrade existing hardware designs without any modifications to your PCB layouts.

Below, I've included a detailed pinout mapping for quick reference.

GPIO Pins

| Name | QFN-60 | QFN-80 | Type | Power Domain | Description | | :--- | :---: | :---: | :--- | :--- | :---: | | GPIO0 | 2 | 77 | Digital IO (FT) | IOVDD | User IO | | GPIO1 | 3 | 78 | Digital IO (FT) | IOVDD | User IO | | GPIO2 | 4 | 79 | Digital IO (FT) | IOVDD | User IO | | GPIO3 | 5 | 80 | Digital IO (FT) | IOVDD | User IO | | GPIO4 | 7 | 1 | Digital IO (FT) | IOVDD | User IO | | GPIO5 | 8 | 2 | Digital IO (FT) | IOVDD | User IO | | GPIO6 | 9 | 3 | Digital IO (FT) | IOVDD | User IO | | GPIO7 | 10 | 4 | Digital IO (FT) | IOVDD | User IO | | GPIO8 | 12 | 6 | Digital IO (FT) | IOVDD | User IO | | GPIO9 | 13 | 7 | Digital IO (FT) | IOVDD | User IO | | GPIO10 | 14 | 8 | Digital IO (FT) | IOVDD | User IO | | GPIO11 | 15 | 9 | Digital IO (FT) | IOVDD | User IO | | GPIO12 | 16 | 11 | Digital IO (FT) | IOVDD | User IO | | GPIO13 | 17 | 12 | Digital IO (FT) | IOVDD | User IO | | GPIO14 | 18 | 13 | Digital IO (FT) | IOVDD | User IO | | GPIO15 | 19 | 14 | Digital IO (FT) | IOVDD | User IO | | GPIO16 | 27 | 16 | Digital IO (FT) | IOVDD | User IO | | GPIO17 | 28 | 17 | Digital IO (FT) | IOVDD | User IO | | GPIO18 | 29 | 18 | Digital IO (FT) | IOVDD | User IO | | GPIO19 | 31 | 19 | Digital IO (FT) | IOVDD | User IO | | GPIO20 | 32 | 20 | Digital IO (FT) | IOVDD | User IO | | GPIO21 | 33 | 21 | Digital IO (FT) | IOVDD | User IO | | GPIO22 | 34 | 22 | Digital IO (FT) | IOVDD | User IO | | GPIO23 | 35 | 23 | Digital IO (FT) | IOVDD | User IO | | GPIO24 | 36 | 25 | Digital IO (FT) | IOVDD | User IO | | GPIO25 | 37 | 26 | Digital IO (FT) | IOVDD | User IO | | GPIO26_ADC0 | 40 | | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO27_ADC1 | 41 | | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO28_ADC2 | 42 | | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO29_ADC3 | 43 | | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO26 | | 27 | Digital IO (FT) | IOVDD | User IO | | GPIO27 | | 28 | Digital IO (FT) | IOVDD | User IO | | GPIO28 | | 36 | Digital IO (FT) | IOVDD | User IO | | GPIO29 | | 37 | Digital IO (FT) | IOVDD | User IO | | GPIO30 | | 38 | Digital IO (FT) | IOVDD | User IO | | GPIO31 | | 39 | Digital IO (FT) | IOVDD | User IO | | GPIO32 | | 40 | Digital IO (FT) | IOVDD | User IO | | GPIO33 | | 42 | Digital IO (FT) | IOVDD | User IO | | GPIO34 | | 43 | Digital IO (FT) | IOVDD | User IO | | GPIO35 | | 44 | Digital IO (FT) | IOVDD | User IO | | GPIO36 | | 45 | Digital IO (FT) | IOVDD | User IO | | GPIO37 | | 46 | Digital IO (FT) | IOVDD | User IO | | GPIO38 | | 47 | Digital IO (FT) | IOVDD | User IO | | GPIO39 | | 48 | Digital IO (FT) | IOVDD | User IO | | GPIO40_ADC0 | | 49 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO41_ADC1 | | 52 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO42_ADC2 | | 53 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO43_ADC3 | | 54 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO44_ADC4 | | 55 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO45_ADC5 | | 56 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO46_ADC6 | | 57 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input | | GPIO47_ADC7 | | 58 | Digital IO / Analog | IOVDD / ADC_AVDD | User IO or ADC input |

QSPI Pins

| Name | QFN-60 | QFN-80 | Type | Power Domain | Reset | Description | | :--- | :---: | :---: | :--- | :--- | :---: | :--- | | QSPI_SD3 | 55 | 70 | Digital IO | QSPI_IOVDD | Pull-Up | QSPI data | | QSPI_SCLK | 56 | 71 | Digital IO | QSPI_IOVDD | Pull-Down | QSPI clock | | QSPI_SD0 | 57 | 72 | Digital IO | QSPI_IOVDD | Pull-Down | QSPI data | | QSPI_SD2 | 58 | 73 | Digital IO | QSPI_IOVDD | Pull-Up | QSPI data | | QSPI_SD1 | 59 | 74 | Digital IO | QSPI_IOVDD | Pull-Down | QSPI data | | QSPI_SS | 60 | 75 | Digital IO | QSPI_IOVDD | Pull-Up | QSPI chip select / USB BOOTSEL |

Crystal Oscillator Pins

| Name | QFN-60 | QFN-80 | Type | Power Domain | Description | | :--- | :---: | :---: | :--- | :--- | :--- | | XIN | 21 | 30 | Analogue (XOSC) | IOVDD | Crystal oscillator; XIN may also be driven by a square-wave source | | XOUT | 22 | 31 | Analogue (XOSC) | IOVDD | Crystal oscillator |

Misc Pins

| Name | QFN-60 | QFN-80 | Type | Power Domain | Reset | Description | | :--- | :---: | :---: | :--- | :--- | :---: | :--- | | RUN | 26 | 35 | Digital In (FT) | IOVDD | Pull-Up | Chip enable / reset_n | | SWCLK | 24 | 33 | Digital In (FT) | IOVDD | Pull-Up | Serial Wire Debug clock | | SWDIO | 25 | 34 | Digital IO (FT) | IOVDD | Pull-Up | Serial Wire Debug data |

USB Pins

| Name | QFN-60 | QFN-80 | Type | Power Domain | Description | | :--- | :---: | :---: | :--- | :--- | :--- | | USB_DP | 52 | 67 | USB IO | USB_QTP_VDD | USB Data +; 27 Ω series resistor required for USB operation |

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What’s New in the RP2350 A4 Stepping?

This stepping addresses several critical issues and introduces highly requested features:

  • GPIO Leakage Bug Fixed: Resolves the notorious RP2350 erratum 9, removing unwanted current leakage on GPIO pins. As a result, external resistors are no longer required to pull inputs low, though they may safely be retained in existing designs.
  • Enhanced Security: Addresses boot ROM exploits, OTP corruption, glitch vulnerabilities, and provides hardened AES encryption for secure applications.
  • Integrated Flash Versions: Introduction of RP2354A/B variants with built-in 2 MB flash, simplifying hardware design and lowering production complexity.
  • Official 5V GPIO Tolerance: Easier interfacing with legacy and retro-computing hardware without needing additional level shifting.

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Why Does the A4 Stepping Matter to You?

  • Goodbye GPIO Leakage. No more worrying about external workarounds, your designs become simpler, cheaper, and more reliable.
  • Stronger Security from the Ground Up. Hardened security improvements protect your products from known vulnerabilities, ensuring safer deployments, particularly important in IoT, industrial, and sensitive embedded projects.
  • Simplified Hardware Design. The RP2354 integrated-flash variant significantly reduces design complexity, saving PCB space and manufacturing costs.
  • Wider Compatibility. Official support for 5 V GPIO levels unlocks compatibility with more devices, sensors, and legacy systems without extra complexity.

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Will the A2 stepping be discontinued?

Raspberry Pi already stopped manufacturing the A2 stepping, shifted all production exclusively to A4, and removed remaining A2 inventory from distribution channels. The A4 stepping is a direct, drop-in replacement for A2, so you shouldn't encounter any issues transitioning to the newer version.

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How Can You Upgrade to the RP2350 A4 Stepping?

Follow these simple steps to leverage the power of RP2350 A4 in your Raspberry Pi Pico projects:

  1. Update your Pico SDK to version 2.1.0 or newer (recommended: 2.2.0).
  2. Rebuild your firmware using the latest SDK to ensure compatibility and utilize new security features.
  3. Switch to RP2350 A4 stepping hardware fully compatible with existing designs but with improved security and reliability.

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Availability and Pricing

  • RP2350A/B A4 Stepping: Now widely available through official Raspberry Pi distributors.
  • RP2354 Integrated Flash Variants: Available soon at around $1.30 to $1.40 per chip, simplifying your designs and saving costs.

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Final Thoughts

The RP2350 A4 stepping significantly upgrades the potential of Raspberry Pi Pico-based designs. Enhanced security, hardware reliability, simpler designs, and broad compatibility make this stepping a turning point for professional and hobbyist projects alike.

Explore our Featured Projects page to discover more Raspberry Pi projects and fresh ideas that will jump-start your next hardware prototype.

{{upsell-project}}

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August 7, 2025
AI Auto-Layout Just Got Smarter

AI Auto-Layout Just Got Smarter

Today, we’re excited to share our Summer Update to Flux AI Auto‑Layout, a collection of improvements designed to make one‑click PCB routing more reliable, transparent, and adaptable to your real‑world workflows.

This update is a set of pragmatic steps toward our vision of Auto‑Layout as your trusted routing assistant. Here's what's improved:

  • Prioritize Nets with Net Types—add a ‘Net Type’ rule manually to your net properties or let Flux do it for you.
  • Relaxed Clearance—results are now cleaner, more manufacturable, and more reliable.
  • Protected Polygons—small copper polygons will be protected from trace intrusions while larger split planes still work as you need them.

Auto‑Layout still works best when guided by thoughtful placement, clear net names, and rulesets—but now it’s a more predictable, collaborative partner in your design process.

Deep Dive Inside the Summer Update

1. Net Priority: Routing in Smart Sequence

Classify your nets into seven priority buckets—High Speed, Analog, Power, Medium Speed, Low Speed, Uncertain, and Ground—and Auto‑Layout will route them in that exact order. Flux will infer the Net Type of each net in your design, but you can check and change the inference by selecting a net and altering the Net Type property.

High‑speed nets go first.
Analog nets get their own quiet lanes.
Power nets find robust copper paths.

This helps ensure your most sensitive signals aren’t forced into awkward detours, delivering a draft layout that mirrors your own routing instincts.

2. Relaxed Clearance: Cleaner Looks over Absolute Shortest Paths

Previous versions of Flux Auto‑Layout often scrunched traces up against neighboring pads or nets to minimize length. We’ve softened that bias so traces now favor open board areas—even if they grow a few mils longer.

  • Cleaner, more “organic” routing reminiscent of a hand‑routed board
  • Improved manufacturability, with wider gaps reducing solder‑bridge risk
  • Slightly longer traces, so plan ahead if you’re in a length‑critical design

Think of it as trading a few extra mils for a huge win in clarity and yield.

3. Protected Polygons: Respect Your Copper

AI Auto-Layout, now, any polygon covering less than 30% of the board area is automatically protected from wires and vias unless you explicitly disable that rule.

Earlier, Auto‑Layout could inadvertently slice through copper pours—especially smaller ones. Now, any polygon covering less than 10% of the board area is automatically protected from wires and vias unless you explicitly disable that rule.

  • No more surprise pour “islands” in your Gerbers
  • Seamless split‑plane support for advanced power or ground schemes
  • Greater peace of mind when working with critical copper fills

How to Make the Most of Auto‑Layout Today

Auto‑Layout shines when you guide it. Here’s a quick workflow that scales from beginners to power users:

  1. Thoughtful Placement. Follow general component placement best practices or watch our video on the placement tips. Group connectors, oscillators, and regulators close to their targets. Leave clear channels for high‑speed and analog nets.
  2. Classify Your Nets
  3. Define Zones & Rulesets. Draw Zones around antennas or heat‑sensitive areas. Create selector‑based rules for common net groups to speed up future projects.
  4. Choose a Workflow
    • Full‑Board Route: One click, start to finish.
    • Hybrid Approach: Pre‑route critical nets, then finish with Auto‑Layout.
    • Placement Check: Run Auto‑Layout early to catch crowded components.

Who Benefits Most

  • Beginners gain confidence by seeing a professionally routed board come together in minutes—while learning best practices from the resulting layouts.
  • Intermediate & Advanced Users offload repetitive low‑critical nets (LED arrays, sensor grids) and focus manual effort on the tricky high‑speed or power sections.

Either way, Auto‑Layout becomes a force multiplier—not a replacement for your expertise.

What’s Next

This Summer Update is a milestone on our roadmap. In the coming months, expect deeper AI understanding of complex topologies, tighter integration with constraint management, and collaborative features that let teams iterate on one layout in real time.

Your feedback is the compass that guides us. Try the Summer Update today—log in, hit “Auto‑Layout”, and tell us where it shined or stumbled via in‑app feedback or our Slack channel. Together, let’s make routing the easiest part of hardware design.

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July 31, 2025
Introducing Copilot Knowledge Base for Flux Engineers

Introducing Copilot Knowledge Base for Flux Engineers

In this post, we’ll show you exactly how to unlock the power of Flux Copilot for yourself: from writing rock-solid triggers to scoping entries at the project, user, and system levels.

Today, EE teams using Flux are already leveraging Knowledge Base to encode their professional know-how—things like project constraints, personal style guides, and industry-vetted best practices—directly into Copilot. In this post, we’ll show you exactly how to unlock that power for yourself: from writing rock-solid triggers to scoping entries at the project, user, and system levels.

Don’t miss out on this opportunity. Take these tips and tricks, apply them today, and watch Copilot transform from a tool into a teammate who thinks—and designs—just like you.

With Knowledge Base, we capture insights at three levels:

  • Project-level: Requirements, calculations, and architecture choices unique to your current board
  • User-level: Your personal style guides, part-family preferences, and schematic conventions
  • System-level: Flux-curated best practices and EE-expert recommendations that benefit everyone

Let’s dive into how it works, why it matters, and—most importantly—how you can craft entries that make Copilot truly think like you.

1. How the Knowledge Base Works & Why It Matters

Flux Copilot’s Knowledge Base entries can be thought of at four levels—from narrow rules to high-level mindsets. When you prompt Copilot, it performs a semantic search, a search that uses sentence structure similarity to find matches , then weaves the most relevant guidance into its reasoning.

Semantic Triggers

Every entry begins with a “use when” phrase. Copilot uses vector search, finding similar items in a dataset by comparing their numerical vector representations (embeddings) instead of relying on exact keyword matches, to match your prompt to the right piece of advice based on semantic similarity.

Context Injection

When you ask Copilot, for example, to generate a buck-converter schematic, it retrieves relevant entries—your project’s input-voltage constraint, your favorite inductor series, or a net-naming rule—and seamlessly injects that context into its response.

Three-Tier Scope

  • Project: Active only within the board you’re editing
  • User: Applies across all your Flux projects
  • System: Flux-approved, peer-reviewed EE best practices

Impact & Examples of Good Results

2. Crafting Effective “Use When” Statements

The use when is the most critical piece of any entry—it tells Copilot when to apply your guidance, based on semantic similarity, not just keywords. If this is off, your advice will never—or always—fire.

  • Keep it short (6–9 words)
  • Lead with your key concept (noun or verb first)
  • Be 100% true to the context you’re capturing
  • Use action verbs (e.g. designing, validating, calculating)
  • Broad vs. Specific:
    • Broad: use when: filtering power rails
    • Specific: use when: designing Pi filters for multi stage power rail
Pro Tip: After Copilot suggests a “use when,” refine it immediately. A small tweak—“for high-speed analog filters” instead of just “for filters”—can mean perfect recall instead of irrelevant noise.

3. Project-Level Knowledge (with Examples)

Project-level entries store all the details that make your current board design one-of-a-kind. They include specific requirements (like voltage tolerances), physical or thermal constraints, chosen topology decisions, and any reference calculations you’ve performed. By capturing the reasoning behind each architectural choice, Copilot can apply context-aware guidance tailored solely to this project. This prevents generic suggestions from slipping through and keeps your design aligned with its unique specifications.

  • Design requirements
    Example:
use when: selecting temperature sensitive components
content: this design is exposed to temperatures of -10 F to 110 F on a Northeastern US State yearly temperature cycle.
  • Design constraints
    Example:
use when: board size constraints
content: Ensure components selected are optimized for a wearable device sized board.
  • Architecture decisions
    Example:
use when: designing a power distribution network
content: Optimize for small size and effeciency for each power component.

4. User-Level Knowledge (with Examples)

User-level entries capture your personal design preferences, workflows, and preferred subcircuit patterns so that Copilot reflects how you work. They let you encode procedural steps—like your favorite LDO selection or filter-design process—directly into Copilot’s memory. With these entries, Copilot adopts your schematic conventions, part choices, and step-by-step habits, producing outputs that feel tailored and familiar. In effect, it transforms Copilot from a generic assistant into one that thinks and advises just as you would.

  • Procedural instructions
    LDO selection
use when: LDO selection process
content: When selecting an LDO, follow a structured four-step workflow: screen basic parameters, filter performance (PSRR, noise), prioritize the key metric, and check optional features.
  • Filter design
use when: filter design process
content: When formalizing filter design, begin with clear specs (ripple, f_c, f_s, attenuation) and then proceed with topology selection, component choice, simulation, and disciplined prototyping.
  • Schematic style guidelines
    Example 1:
use when: naming nets for differential pairs  
content: Prefix with SIG_DP_ or SIG_DM_ and suffix with _N/_P for polarity clarity.  
  • Example 2:
use when: naming nets with series resistors
content: Add a suffix _R to the name of the incoming net to the resistor and use it for the outgoing net name.  
  • Tips for specialized circuits
    Example:
use when: designing op-amp instrumentation amplifiers  
content: Add 10 Ω series resistors on each input to decouple source capacitance.  
  • Component-specific instructions
    Example:
use when: using TI SN65HVD230 CAN transceiver  
content: Place 120 Ω termination resistors close to the transceiver and add 0.1 µF decoupling on VCC.

5. System-Level Knowledge (How We Build It)

Our EE team crafts system entries with the highest rigor—so every user benefits from vetted best practices.

  1. Source & Draft
    • Extracted from whitepapers, application notes, and our expert’s experience
  2. Peer Review
    • Our team of senior engineers validate technical accuracy and remove any vendor bias
  3. Semantic Validation
    • We test “use when” triggers against hundreds of prompt variations to ensure relevance
Note: Every word is chosen deliberately—“use when” must be as true as the “content” it triggers.

6. Managing Your Knowledge Base

As your KB grows, keep it relevant and helpful by:

  1. Watching Scopes
    • ✅ Don’t mix project-specific facts into user-level entries
    • Edit user entries: Profile → Knowledge → User Knowledge
    • Edit project entries: Project → Knowledge → Project Knowledge
  2. Monitoring Performance
    • Hit the 👎 thumbs-down when Copilot misapplies an entry or forms a bad response
    • Identify entries causing loops: “Why does it always suggest the same value for an inductor?”
  3. Signs of Harmful Entries
    • Over-fixation: Copilot insists on one solution for every design
    • Inaccuracies: Obvious part-selection errors or illogical guidance
  4. Regular Audits
    • Periodically review and prune outdated or narrow entries
    • Elevate broadly useful user entries to system level for team-wide benefit

Start Building Your KB Today

Adding your knowledge to Copilot doesn’t just make it smarter—it makes you faster, more consistent, and more confident. Open Flux Copilot, watch for that “Knowledge Suggestion” button in the response, and begin teaching your AI teammate how you design. Over time, your Knowledge Base becomes a living encyclopedia of your best practices—project by project, decision by decision.

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July 18, 2025