Overview

The RP2040 is the flagship custom-designed microcontroller IC manufactured by Raspberry Pi Ltd. Powering the Raspberry Pi Pico, Pico W, Adafruit Feather RP2040, SparkFun Thing Plus, and hundreds of commercial keyboards and audio synthesizers, it features a dual-core 32-bit ARM Cortex-M0+ processor running at 133 MHz133\text{ MHz}.

The RP2040 stands out for its large 264 KB264\text{ KB} multi-bank SRAM, native USB 1.1 Host and Device controller (supporting Drag-and-Drop UF2 bootloading over USB), and groundbreaking Programmable I/O (PIO) subsystem—8 independent state machines capable of executing user assembly code to emulate hardware protocols (VGA video output, DVI/HDMI, I2S audio, WS2812 LED timing, and custom parallel interfaces) offloading the main CPU cores completely.

Quick reference

CPU ArchitectureDual-core ARM Cortex-M0+ at 133 MHz133\text{ MHz} (Flexible clock up to 250 MHz+250\text{ MHz}+)
SRAM Memory264 KB264\text{ KB} in 6 independent SRAM banks
External Flash (XIP)Supports up to 16 MB16\text{ MB} external QSPI NOR Flash with XIP cache
Package56-pin QFN (7×7 mm7 \times 7\text{ mm}) with exposed ePad
Programmable I/O (PIO)8 state machines across 2 PIO blocks
USB InterfaceIntegrated USB 1.1 Controller (Host and Device) with internal PHY
I/O & Analog30 GPIO pins, 4-channel 12-bit ADC (500 kSPS500\text{ kSPS})
DMA Controller12-channel DMA controller
BootloaderBuilt-in ROM USB Mass Storage Bootloader (UF2 Drag-and-Drop)

Pinout (Raspberry Pi Pico Board Form Factor)

text
                       ┌─────────────┐
        (GP0/UART0 TX) [ GP0     VBUS] (5V USB Input)
        (GP1/UART0 RX) [ GP1    VSYS ] (1.8V-5.5V Main Power Input)
                       [ GND     GND ]
                 (GP2) [ GP2    3V3_EN] (3.3V Regulator Enable)
                 (GP3) [ GP3    3V3_OUT] (3.3V Power Output)
        (GP4/I2C0 SDA) [ GP4    ADC_VREF]
        (GP5/I2C0 SCL) [ GP5    GP28 ] (ADC2)
                       [ GND     GND ]
                 (GP6) [ GP6    GP27 ] (ADC1)
                 (GP7) [ GP7    GP26 ] (ADC0)
        (GP8/SPI0 RX)  [ GP8    RUN  ] (Reset Pin)
        (GP9/SPI0 CS)  [ GP9    GP22 ]
                       [ GND     GND ]
        (GP10/SPI0 SCK)[ GP10   GP21 ]
        (GP11/SPI0 TX) [ GP11   GP20 ]
        (GP12/I2C1 SDA)[ GP12   GP19 ] (SPI1 TX)
        (GP13/I2C1 SCL)[ GP13   GP18 ] (SPI1 SCK)
                       [ GND     GND ]
                (GP14) [ GP14   GP17 ] (SPI1 CS)
                (GP15) [ GP15   GP16 ] (SPI1 RX)
                       └─────────────┘

Specifications

ParameterSymbolMinTypMaxUnitConditions
Core VoltageVDDV_{DD}1.051.101.20VInternal LDO regulated
I/O VoltageIOVDDIOVDD1.83.33.6VGPIO supply rail
Active Core CurrentIRUNI_{RUN}—1830mADual cores active at 133 MHz
Dormant Power CurrentIdormI_{dorm}—0.181.0mAClock shut down
GPIO Output Drive CurrentIOH/OLI_{OH/OL}24 / 812mAProgrammable 2/4/8/12mA
ADC Sample RatefSAMPf_{SAMP}—500—kSPS12-bit ENOB = 8.7 bits

Wiring (Bare RP2040 Minimal Chip Implementation)

Designing a custom PCB with the bare RP2040 IC requires:

  1. QSPI Flash IC: Winbond W25Q16 (2 MB2\text{ MB}) or W25Q128 (16 MB16\text{ MB}) connected to QSPI pins.
  2. Crystal Oscillator: 12.000 MHz12.000\text{ MHz} crystal connected to XIN and XOUT with 27 pF27\text{ pF} load capacitors.
  3. Decoupling Capacitors: 100 nF100\text{ nF} ceramic caps on all DVDD, IOVDD, and ADC_AVDD supply pins.

Example (MicroPython Dual-Core Code)

python
import time
import _thread
from machine import Pin

led = Pin(25, Pin.OUT)

# Task running independently on Core 1
def core1_task():
    while True:
        print("Hello from RP2040 Core 1!")
        time.sleep(2)

# Start Core 1 thread
_thread.start_new_thread(core1_task, ())

# Main loop running on Core 0
while True:
    led.toggle()
    time.sleep(0.5)

Common mistakes

  • Leaving RUN pin floating: The RUN reset pin on the RP2040 has no internal pull-up. Leaving it floating causes random MCU resets. Connect a 10 kΩ10\ \text{k}\Omega pull-up resistor to 3.3V.
  • Forgetting 33 ohm series termination resistors on USB D+/D-: The internal USB PHY requires 27 Ω…33 Ω27\ \Omega \dots 33\ \Omega external series resistors on USB_DP and USB_DM lines for USB 1.1 signal integrity.

Notes

  • RP2040 vs STM32F103 vs ESP32: RP2040 offers 264 KB264\text{ KB} RAM with PIO state machines; STM32F103 offers 20 KB20\text{ KB} RAM; ESP32 adds Wi-Fi/Bluetooth.

Assets & downloads