RP2040 Explained: The Chip Behind Raspberry Pi Pico

When the RP2040 landed on my PCB design bench in early 2021, I wasn’t expecting much from a $1 microcontroller. After all, the embedded market is flooded with cheap silicon. But this chip changed my perspective on what’s possible at the entry-level price point. The rp2040 chip isn’t just another microcontroller. It’s Raspberry Pi’s first venture into custom silicon design, and they absolutely nailed it.

This deep dive explores the architecture, specifications, and unique capabilities that make the raspberry pi rp2040 stand out in a crowded market. Whether you’re evaluating it for a commercial product or your next hobby project, understanding what’s inside this tiny 7mm × 7mm package will help you leverage its full potential.

What Is the RP2040?

The RP2040 is a dual-core ARM Cortex-M0+ microcontroller designed entirely in-house by Raspberry Pi Ltd. Announced on January 21, 2021, it marked the Foundation’s entry into the microcontroller market after years of success with their single-board computers. Unlike their previous products that relied on Broadcom SoCs, this chip represents genuine custom silicon developed in Cambridge, UK.

The naming convention itself tells a story. “RP” stands for Raspberry Pi. The “2” indicates two processor cores. The “0” represents the ARM Cortex-M0+ architecture. The “4” encodes the RAM capacity (floor(log2(264/16)) = 4). The final “0” indicates zero on-chip flash memory, a deliberate design decision we’ll explore later.

Manufactured by TSMC on their 40nm process node, the rp2040 chip occupies just two square millimeters of silicon. This modern fabrication process delivers high performance with low power consumption, making it suitable for battery-operated applications while keeping costs remarkably low.

RP2040 Technical Specifications

Understanding the hardware capabilities helps you assess whether the raspberry pi rp2040 fits your project requirements. Here’s the complete specification breakdown:

Core Specifications

Component	Specification
Processor	Dual-core ARM Cortex-M0+ @ 133MHz
Architecture	32-bit ARMv6-M
SRAM	264KB (6 independent banks)
On-chip Flash	None (external QSPI)
ROM	16KB bootloader
Bus Fabric	AHB-Lite crossbar
DMA	12 channels
Package	QFN-56 (7mm × 7mm)
Process Node	TSMC 40nm
Operating Voltage	1.8V to 3.3V core

Peripheral Specifications

Peripheral	Quantity/Details
GPIO	30 multi-function pins
UART	2
SPI	2
I2C	2
PWM	16 channels (8 slices × 2 outputs)
ADC	4 channels, 12-bit, 500ksps
Timer	1 (64-bit)
RTC	1
Watchdog	1
USB	1.1 Host/Device with PHY
PIO	2 blocks × 4 state machines

Electrical Characteristics

Parameter	Value
Supply Voltage (DVDD)	1.1V nominal
I/O Voltage (IOVDD)	1.8V to 3.3V
Idle Current	~24mA @ 48MHz
Active Current	~93mA @ 133MHz
Sleep Current	~180μA typical
Operating Temperature	-20°C to +85°C

The Dual-Core Architecture

The RP2040 implements two identical ARM Cortex-M0+ cores that share access to all peripherals and memory. Unlike asymmetric multi-core designs where cores have different capabilities, both RP2040 cores are fully symmetric. Either core can boot first, access any peripheral, or handle any interrupt.

This symmetric design provides genuine flexibility. You can dedicate one core entirely to time-critical tasks like motor control while the other handles user interface and communication. The cores communicate through shared memory and can signal each other using hardware spinlocks and mailbox-style interrupts.

The Cortex-M0+ itself deserves recognition. Despite being ARM’s smallest, lowest-power processor design, it handles 32-bit operations efficiently. The two-stage pipeline keeps instruction throughput high while the deterministic interrupt latency (just 15 cycles) makes real-time applications practical.

What makes the rp2040 chip particularly interesting is the bus fabric connecting these cores. The fully-connected crossbar switch allows both cores and the DMA controller to access different SRAM banks simultaneously without contention. Six independent SRAM banks mean careful memory layout can virtually eliminate bus conflicts during parallel operation.

Programmable I/O: The Game-Changing Feature

If there’s one feature that distinguishes the raspberry pi rp2040 from every competing microcontroller, it’s the Programmable I/O (PIO) subsystem. This isn’t just another peripheral. It’s essentially four additional tiny processors per PIO block, eight total, dedicated exclusively to I/O operations.

What PIO Actually Does

Traditional microcontrollers handle communication protocols through dedicated hardware peripherals or software bit-banging. Hardware peripherals are fast but inflexible. Bit-banging is flexible but consumes CPU cycles and struggles with precise timing. PIO eliminates this trade-off entirely.

Each PIO state machine executes simple assembly programs from shared instruction memory. With only nine instructions available, the programming model is minimal yet surprisingly powerful:

Instruction	Function
JMP	Conditional/unconditional branch
WAIT	Pause until condition met
IN	Shift bits into input shift register
OUT	Shift bits out of output shift register
PUSH	Transfer ISR contents to RX FIFO
PULL	Transfer TX FIFO contents to OSR
MOV	Move data between registers
IRQ	Set/clear interrupt flags
SET	Write immediate value to pins

Real-World PIO Applications

The state machines execute deterministically at up to system clock speed (133MHz), enabling cycle-accurate timing impossible to achieve with software. Engineers have implemented:

• WS2812 LED drivers without CPU involvement
• VGA video output using three state machines
• SD card SDIO interfaces for high-speed storage
• Custom serial protocols for legacy devices
• Audio I2S for codec interfacing
• Parallel camera interfaces for image capture
• DPI display output for LCD panels

A single PIO block with four state machines and 32 instruction words can implement multiple complex protocols simultaneously. The SD card driver, for instance, uses just 18 instructions across three state machines, leaving room for additional interfaces in the same PIO block.

External Flash: A Design Philosophy

The RP2040 lacks on-chip flash memory, which initially seems like a limitation. However, this stateless design is actually intentional and advantageous.

Without embedded flash, you choose the appropriate storage density for your application. Need 2MB? Use a 2MB flash chip. Need 16MB for data logging? Just change the external component. Commodity QSPI flash parts cost pennies in volume, often less than the premium charged for on-chip flash equivalents.

The chip executes code directly from external flash through an XIP (execute-in-place) cache. This 16KB cache provides near-internal-flash performance for typical code patterns while allowing much larger programs than integrated flash would permit at this price point.

Additionally, the external flash makes firmware updates trivial. The RP2040’s built-in USB bootloader presents the flash as a mass storage device. Drag a UF2 file onto the drive, and the firmware updates automatically. No programmers, no special software, no driver installation.

RP2040 vs Competing Microcontrollers

How does the rp2040 chip stack up against popular alternatives? This comparison helps contextualize its position in the market:

Microcontroller Comparison

Feature	RP2040	ATmega328P	STM32F103	ESP32-S3
Cores	2	1	1	2
Architecture	Cortex-M0+	AVR 8-bit	Cortex-M3	Xtensa LX7
Clock Speed	133MHz	20MHz	72MHz	240MHz
SRAM	264KB	2KB	20KB	512KB
Flash	External	32KB	64KB	External
USB	Yes (built-in)	No	Yes	Yes
WiFi/BT	No*	No	No	Yes
PIO	8 state machines	No	No	No
Unit Price	~$1	~$2	~$3	~$3

*The Pico W adds wireless via the CYW43439 chip

The RP2040 excels in raw memory capacity, multi-core processing, and I/O flexibility. The ESP32-S3 wins on wireless integration and raw clock speed. Traditional 8-bit parts like the ATmega maintain advantages in extreme low-power applications and broad ecosystem support.

Boards Using the RP2040

The raspberry pi rp2040 has spawned an ecosystem of development boards beyond the official Raspberry Pi Pico:

Manufacturer	Board	Notable Features
Raspberry Pi	Pico	Reference design, $4
Raspberry Pi	Pico W	WiFi + Bluetooth
Adafruit	Feather RP2040	Feather ecosystem, LiPo charging
Adafruit	QT Py RP2040	Tiny form factor, STEMMA QT
SparkFun	Pro Micro RP2040	Pro Micro footprint, USB-C
SparkFun	Thing Plus RP2040	Qwiic connectors, 16MB flash
Arduino	Nano RP2040 Connect	WiFi, IMU, microphone
Pimoroni	Tiny 2040	Ultra-compact, RGB LED
Waveshare	RP2040-Zero	Minimal design, castellated pads

Each board targets different use cases while sharing the same powerful core silicon. The official Pico remains the most cost-effective option, while third-party boards add features like additional flash, wireless connectivity, or specialized form factors.

Programming the RP2040

The RP2040 supports multiple development environments and programming languages:

Officially Supported

• C/C++ SDK: Full hardware access, maximum performance
• MicroPython: Beginner-friendly, interactive development
• CircuitPython: Adafruit’s Python variant with extensive library support

Community Supported

• Arduino IDE: Familiar environment with earle-philhower core
• Rust: Memory-safe embedded development
• Go (TinyGo): Compiled Go for microcontrollers
• Ada: Safety-critical development
• Zig: Modern systems programming
• TypeScript: Via Pico-js runtime

The official C/C++ SDK provides the deepest hardware access and best performance. MicroPython offers rapid prototyping with its interactive REPL. Arduino support brings familiar libraries and simplified syntax for hobbyists transitioning from other platforms.

Useful Resources and Downloads

Official Documentation

• RP2040 Datasheet: datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf
• Hardware Design Guide: datasheets.raspberrypi.com/rp2040/hardware-design-with-rp2040.pdf
• Pico C/C++ SDK: github.com/raspberrypi/pico-sdk
• Pico MicroPython: micropython.org/download/RPI_PICO/
• Pico Design Files: raspberrypi.com/documentation/microcontrollers/raspberry-pi-pico.html

Development Tools

• Thonny IDE: thonny.org (MicroPython development)
• VS Code + Pico Extension: Integrated C/C++ development
• PIO Emulator: github.com/soundpaint/rp2040pio (PIO debugging)

Community Resources

• Raspberry Pi Forums: forums.raspberrypi.com
• RP2040 GitHub Examples: github.com/raspberrypi/pico-examples
• MicroPython Documentation: docs.micropython.org/en/latest/rp2/

Long-Term Availability

For commercial products, supply continuity matters enormously. Raspberry Pi has committed to manufacturing the RP2040 until at least January 2041, a 20-year production guarantee. This longevity commitment, combined with multiple authorized distributors worldwide, makes the chip viable for products requiring extended lifecycle support.

The $1 unit pricing at volume removes cost barriers that often push engineers toward inferior alternatives. When the silicon costs less than passive components on your BOM, design decisions can focus purely on technical merit.

Frequently Asked Questions

What makes the RP2040 different from other microcontrollers?

The RP2040 distinguishes itself through its Programmable I/O (PIO) subsystem, dual symmetric Cortex-M0+ cores, and exceptional value. The eight PIO state machines enable custom hardware interfaces impossible on traditional microcontrollers without FPGAs. The 264KB SRAM, roughly 130 times more than an Arduino Uno, eliminates memory constraints for most embedded applications. At approximately $1 per chip, it delivers ARM performance at commodity pricing.

Does the RP2040 have built-in WiFi or Bluetooth?

No, the base rp2040 chip lacks wireless connectivity. Raspberry Pi addresses this with the Pico W board, which pairs the RP2040 with an Infineon CYW43439 wireless module providing 2.4GHz WiFi and Bluetooth 5.2. If your project requires wireless communication, select a Pico W variant or add an external wireless module to a standard RP2040 board.

Can the RP2040 run an operating system?

The raspberry pi rp2040 cannot run Linux or other full operating systems due to its Cortex-M0+ architecture, which lacks memory management units required for virtual memory. However, it runs real-time operating systems (RTOS) like FreeRTOS excellently. For most microcontroller applications, bare-metal programming or MicroPython provides sufficient capability without OS overhead.

How does the RP2040 compare to ESP32?

Both chips target similar applications but with different strengths. The ESP32 integrates WiFi and Bluetooth directly, runs at higher clock speeds, and suits IoT applications. The RP2040 offers superior I/O flexibility through PIO, better documentation, lower cost, and simpler power management. Choose ESP32 for wireless-centric projects; choose RP2040 for complex I/O requirements, cost-sensitive designs, or applications demanding deterministic timing.

Why doesn’t the RP2040 have built-in flash memory?

The external flash design was intentional, not a limitation. It allows designers to select appropriate flash density (2MB to 16MB typically) for their application requirements. Commodity QSPI flash costs less than equivalent on-chip flash would, reducing overall system cost. The execute-in-place (XIP) cache maintains performance, while the USB mass storage bootloader simplifies firmware updates. This architecture enables larger programs than integrated flash would permit at this price point.

Final Thoughts

The RP2040 represents what happens when experienced engineers design silicon specifically for the maker and embedded communities they understand intimately. The dual-core architecture provides genuine parallel processing capability. The PIO subsystem solves interface problems that traditionally required expensive FPGAs or frustrating bit-banging workarounds. The external flash philosophy prioritizes flexibility over false simplicity.

After integrating this chip into numerous projects over the past few years, my appreciation for its design has only grown. The documentation quality exceeds most professional microcontroller vendors. The community has developed libraries covering virtually every common peripheral. The $1 pricing eliminates any hesitation about experimenting with new applications.

Whether you’re building a commercial product requiring long-term supply assurance or your next weekend project, the raspberry pi rp2040 delivers capability far exceeding its modest price tag. The Programmable I/O alone justifies evaluating it for any project involving non-standard interfaces or precise timing requirements.

Raspberry Pi didn’t just enter the microcontroller market. They raised the bar for what entry-level silicon should offer.