Debug (SWD)

BOOTSEL_BUTTON

RP2040

 can be used in both Device and Host mode. The Raspberry Pi Pico exposes it as a USB Micro B port that can be used both to access the USB bootloader (BOOTSEL mode) stored in the 

USB Micro B

The board has a builtin LED that is connected to the 

. So, It can be toggled on or off by setting that pin to HIGH/LOW correspondingly.

General Purpose I/O

Here is the Blink example code provided by Arduino IDE that turns the on board LED on and off every second. As you can see, the 

 is a constant that contains the pin number that is connected to the built-in LED of the board. In the Raspberry Pi Pico, the value of 

In order to program the Raspberry Pi Pico (i.e., copy your code to its Flash memory), you should hold down the BOOTSEL button when the board is being restarted.

To do this, unplug the power from the board, then hold the BOOTSEL button down and then connect the USB. The Pico will then appear as a USB Mass Storage Device to your computer. By dragging a special '.uf2' file onto the disk, you can write file to the Flash and restart the Raspberry Pi Pico Pico.

BOOTSEL Button

The main processor of the Raspberry Pi Pico board is the RP2040 microcontroller made by Raspberry Pi company. It's a 32-bit processor in QFN56 package. The RP2040 features Dual Cortex M0+ processor cores, up to 133MHz, 264kB of embedded SRAM and 30 GPIO.

RP2040 Microcontroller

Connected to the ground (close coupled ground for differential USB signals).

 supports the SWD debugging interface and these pins expose that interface so that it could be connected to the debug probe (a separate piece of hardware that can be purchased from Raspberry Pi). It's also possible to use another Raspberry Pi Pico as a debugger.

The Raspberry Pi Pico is a compact and versatile microcontroller development board based on the RP2040 chip. The Raspberry Pi Pico offers a balance of performance, low power consumption, and affordability. With dual-core Arm Cortex-M0+ processors, flexible I/O options, and support for multiple programming languages like C, C++, and MicroPython, the Pico opens up a range of possibilities for creating interactive and intelligent devices. Some major features include:

Dual-core Arm Cortex-M0+ processor, clocked up to 133 MHz

264 KB of SRAM and 2 MB of onboard flash memory

26 multi-function GPIO pins including 3 ADC

Provides 2 PIO (Programmable I/O) for custom peripheral interfacing

Support most of the well-known protocol like I2C, SPI, UART and PWM

The Raspberry Pi Pico is a compact microcontroller board with various components and headers that make it versatile and easy to use for different projects. Below are the key element of the board you may be interested to know about:

Raspberry Pi Pico Dimensions

The Raspberry Pi Pico has 40 pins in total, arranged in two rows of 20 pins each.

Raspberry Pi Pico Pin Headers

The micro-USB port, located at the edge of the board, is the primary way to connect the Raspberry Pi Pico to a computer for power and programming. It’s compatible with a standard micro-USB cable and handles data and power input (5V).

Raspberry Pi Pico Micro-USB Port

This small button is used to enter programming mode. By pressing and holding the Bootsel button while connecting the Pico to power, the board goes into USB mass storage mode, allowing you to upload firmware or access the file system.

Raspberry Pi Pico Bootsel Button

The Pico has a built-in LED that can be controlled via 

. It is often used to provide visual feedback for various applications, such as status indication or testing purposes.

Raspberry Pi Pico LED Indicator

 processor designed by Raspberry Pi. It powers the entire board and provides the processing capability for Pico’s operations.

Arm Cortex-M0+

Raspberry Pi Pico RP2040 Microcontroller

A small set of pads is available for Serial Wire Debug (SWD) access, which allows low-level debugging and direct communication with the 

 chip. Although not pre-soldered, these pads can be used by advanced users to connect external debuggers.

Raspberry Pi Pico Debug Header (SWD)

In the back of the board are various test pads allowing you to hook into different areas such as USB data pins, triggering boot select, or the LED pin.

Raspberry Pi Pico Test Pads

The Raspberry Pi Pico offers a few flexible options for powering the board, making it suitable for various project setups. Here are the main ways to power the Pico:

The simplest and most common way to power the Raspberry Pi Pico is via the micro-USB port. When connected to a computer or USB power adapter, the micro-USB provides a stable 5V input to the board. This port not only powers the board but also serves as the primary connection for programming and data transfer.

 pin is directly connected to the 5V power provided by the USB input. If your project requires direct access to the 5V input, you can use this pin to power additional external components. This pin outputs 5V only when the board is powered via the USB port.

Power

Raspberry Pi Pico VBUS Pin

 pin is the primary power input pin on the Pico, offering an alternative to the micro-USB port. This pin can accept a voltage range from 1.8V to 5.5V, making it compatible with various external power sources, such as batteries.

For example, a common power source like a 3.7V LiPo battery can connect directly to the 

Raspberry Pi Pico VSYS Pin

The 3V3 pin is an output from the Pico’s onboard voltage regulator, providing a stable 3.3V for other components or sensors in your circuit.

The onboard regulator converts the USB 5V or 

 input to a stable 3.3V output, suitable for most low-power components used alongside the Pico.

Raspberry Pi Pico 3V3 (Out) Pin

) pins are available in multiple locations across the Pico’s pin headers. All external components that need a reference ground should be connected to any of these 

Ground

Raspberry Pi Pico GND Pins

For advanced users, the Raspberry Pi Pico can be powered directly by supplying a 3.3V input on the 

 pin. However, caution should be taken here as it bypasses the regulator, and any over-voltage could damage the board.

This option is mostly used when the Pico is part of a larger circuit with a commonly regulated 3.3V power source.

 microcontroller comes with a variety of built-in peripherals designed to support a wide range of applications. Here’s a breakdown of the main peripherals that are mostly available in Raspberry Pi Pico pinout on the board:

The Pico has 26 General Purpose Input/Output (GPIO) pins, which can be configured for digital input or output. These pins offer high flexibility and can be programmed to perform various functions in custom circuits.

16 of the GPIO pins support PWM, enabling the generation of variable-width pulses. PWM is widely used for applications such as dimming LEDs, controlling motor speed, or generating audio signals.

The Pico includes two I2C controllers, allowing communication with I2C-compatible devices like sensors, displays, and EEPROMs. Each controller can communicate with multiple devices over a shared bus.

The board provides two SPI controllers, ideal for high-speed communication with SPI-enabled peripherals. SPI is commonly used for fast data transfer with components like SD cards, displays, and certain sensors.

UART (Universal Asynchronous Receiver/Transmitter)

With two UART controllers, the Pico can handle serial communication with other devices that use standard serial protocol, such as GPS modules, Bluetooth modules, external microcontrollers, or computers.

The Pico includes 3 ADC channels, allowing it to measure analog signals from sensors and other components. Each ADC channel has a 12-bit resolution, which translates analog voltages into digital values.

 features two Programmable I/O (PIO) blocks, each with 4 state machines. These allow users to implement custom protocols and control signals that might not be natively supported by the other peripherals.

Multiple hardware timers on the RP2040 allow for precise control of timed events, such as delays, periodic interrupts, or time-sensitive applications.

The RP2040 microcontroller includes a built-in USB 1.1 controller, enabling direct USB communication when connected to a computer. This controller supports USB Device Mode, allowing the Pico to emulate devices like keyboards, mice, or serial interfaces.

Programming the Raspberry Pi Pico offers multiple options, allowing developers to choose from a range of tools and languages that best suit their project needs and experience level. Here are the main programming options available for the Pico:

MicroPython is a popular, lightweight implementation of Python, specifically designed for microcontrollers. It is ideal for beginners due to its simplicity and ease of use.

The official C/C++ Software Development Kit (SDK) for the Raspberry Pi Pico provides low-level access to the board’s features and peripherals. It is a comprehensive option for advanced users who want full control over hardware.

The Pico can be programmed using the popular Arduino IDE thanks to official support in the Arduino Core for 

. This option allows users familiar with the Arduino ecosystem to develop projects with the Pico using standard Arduino libraries and syntax.

CircuitPython, developed by Adafruit, is another Python-based option similar to MicroPython. It includes additional features, such as built-in drivers for Adafruit components, making it convenient for users who frequently work with Adafruit hardware.

PlatformIO is a versatile and powerful development environment supporting multiple platforms, including 

. It integrates with IDEs like Visual Studio Code and offers a streamlined workflow for writing, testing, and deploying code to the Pico.

Raspberry Pi Pico Keyboard and Gamepad HID with an NES Controller!

Raspberry Pi Pico 200Khz Digital Oscilloscope

PicoLight - Minimalist Light for Product Shots

Getting Started With REPL on Raspberry Pi Pico Using Rshell

Get comprehensive details on the Raspberry Pi Pico development board: Pinout, Powering options, Peripherals & Programming.

The BOOTSEL button is used to enter USB mass storage mode for firmware upload.

To update, press and hold BOOTSEL while connecting to USB, then drag and drop the new firmware file.

Yes, it can control motors through PWM output on its GPIO pins.

PIO blocks allow for custom hardware interfaces and protocols not natively supported by the 

Yes. The Real-time Clock (RTC) provides time in a human-readable format and can be used to generate interrupts at specific times

Yes, you can power the Pico with batteries using the 

 pin. The board doesn’t have any charger circuit. So, you have to handle that via custom circuit yourself.

The RP2040 can run at a maximum clock speed of 133 MHz.

Each GPIO pin can handle up to 12 mA, with a maximum of 50 mA across all pins.

Yes, with Arduino IDE support, you can use many Arduino libraries with the Pico. But you have to check the documentation of each library to be sure the maintainer added support for the Raspberry Pi Pico.

It has 2 MB of onboard flash memory but no storage expansion slots.

To reset, press and hold the BOOTSEL button while connecting the Pico to power or use an external reset circuit.

Yes, lightweight models can be run using TensorFlow Lite for Microcontrollers.

No, the standard Raspberry Pi Pico does not have built-in wireless connectivity.

 pins in the board can be used for PWM. The 

 has 8 independent PWM generators called slices, which each have two channels making it 16 PWM channels. The PWM frequency can be clocked from 8Hz to 62.5Mhz.

To generate a PWM signal in Arduino IDE on one of the PWM capable pins, you can use the 

The duty cycle of the PWM signal can be adjusted using the second parameter. By default the PWM uses the 8-bit resolution which means you can specify a value between 0 to 255 for the duty cycle.

In order to do any customization on the PWM signal, like changing the frequency or duty cycle, you can utilize functions like:

The Raspberry Pi Pico has 26 multi-function GPIO pins, which can be used for digital input or output and configured for different communication protocols. They are named in the back of the board as 

All GPIOs support digital input and output, but 

 can also be used as inputs to the chip’s Analogue to Digital Converter (ADC).

 has also the following four GPIO pins that are used for the internal functions of the board:

 OP Controls the on-board SMPS Power Save pin

A GPIO pin can be used either as input or output pin. In the Arduino IDE, his should be specified first using the 

, the given pin will be internally connected to the 3.3V so that if the given pin is floated (i.e. you don't connect it to to either of 3.3V or GND) it will be read as 

The Raspberry Pi Pico has the ability to set the current a pin can supply. The available current limits are 2mA, 4mA, 8mA and 12mA. By default, on a reset, the setting is 4mA (same as `pinMode(x, 

)`). You can also use the following values instead:

When the pin mode is set, you can read the value of an input pin like this:

Also to write a digital value to a pin, you can call the 

 function passing one of the constant values 

 along with the pin number to write it to:

GPIO

GP0,GP1,GP2,GP3,GP4,GP5,GP6,GP7,GP8,GP9,GP10,GP11,GP12,GP13,GP14,GP15,GP16,GP17,GP18,GP19,GP20,GP21,GP22,GP26,GP27,GP28

 pin, remember to connect at least one of the 

 pin of the board to your power supply ground. There are seven 

 pins in the Raspberry Pi Pico, plus one exposed in the debug pins.

As it's connected to the USB ground wire, when the board is powered via USB, the 

 pins are already grounded to USB ground.

This is the main input voltage to the board in case it's not going to be powered by USB. It can vary in the range of 1.8V to 5.5V, and is used by the on-board SMPS to generate the 3.3V for the 

VSYS

This is connected to the micro-USB port input voltage. It is nominally 5V and when the USB is not connected or not powered, it will be in 0V level.

 (which is not exposed in the board) is set up via a voltage divider to monitor the existence of 

VBUS

This pin connects to the on-board SMPS enable pin, and is pulled high (to the 

) via a 100kΩ resistor. When you connect this pin to 

, it disables the 3.3V (which also de-powers the 

). So, you can use this pin to implement the power button for your board.

3V3_EN

The pin connects to the main 3.3V supply to the 

 and its I/O and is generated by the on-board SMPS. It can provide power to an external circuit. Th maximum output current depends on the 

 voltage. It is recommended to keep the load on this pin less than 300mA.

3V3 (OUT)

 and has an internal (on-chip) pull-up resistor to 3.3V of about ~50kΩ.

This pin is the ADC power supply and reference voltage. It is generated on Raspberry Pi Pico by filtering the 3.3V supply. 

The board has a 12 bit ADC which means any analog input voltage will be converted to a number between 0 to 4095. By default the board considers the 3.3V as a reference and consider a signal on that level as 4095 and any signal with a value less than 3.3V will be converted to a number between 0 to 4094 accordingly. When the 

 is provided with another voltage level, that voltage will be considered as max (4095) and all the voltage levels below that will be mapped accordingly.

 can be powered at a nominal voltage between 1.8V and 3.3V, but the performance of the ADC will be compromised at voltages below 2.97V.

ADC_VREF

. In the Raspberry Pi Pico, there is a separate analog ground plane running under these signals and terminating at this pin. If the ADC is not used or ADC performance is not critical, this pin can be connected to digital ground.

AGND

 processor of the Raspberry Pi Pico has a 4 channel 12-bit ADC at 500ksps, where three of them are exposed in the board as 

. The 12-bit ADC provides the resolution of 4096 value which means any analog input signal between 0V to 3.3V applied to these pins gets mapped proportionately to a value between 0 to 4095.

There is also another ADC channel that is dedicated to the internal temperature sensor in the 

. You can read the value in Arduino IDE by calling the 

. If you're supplying an external power to 

, then you have to specify that as a parameter to this method. Otherwise it assumes the 3.3V is used and the result will not be correct. This reading is not exceedingly accurate and of relatively low resolution.

ADC0,ADC1,ADC2

 is the Serial Clock pin used as clock signal between two chips communicating via the two-wire serial interface (TWI) also known as I2C.

I2C1 SCL

I2C0 SCL

I2C0 SDA

I2C1 SDA

 (Serial Clock) is a clock signal used to synchronize the processor and peripherals. The line is used as a shared line for all connected peripherals to a SPI bus.

SPI0 SCK

SPI1 SCK

 (Chip Select) is connected to each peripheral device and controller can enable or disable specific device using that. When controller set this pin for a specific device to low, it means that devices can communicate with the controller. When it's high, it means the device is disabled should ignore any data coming from the processor (i.e., 

). This enables the controller to connect to multiple SPI enabled peripherals and sharing the same 

SPI0 CSn

SPI1 CSn

 is for receiving data from the peripheral (e.g. a SPI LCD module) via SPI channel.

SPI0 RX

SPI1 RX

 is for sending data to the peripherals (e.g. a SPI LCD module) via SPI.

SPI0 TX

SPI1 TX

 is for sending data in a serial communication via UART channel.

USART

UART0 TX

UART

 is for receiving data in a serial communication via UART channel.

UART0 RX

UART1 RX

UART1 TX

The Raspberry Pi Pico supports the SWD debugging protocol to debug the code running on he 

 pin is used for debug data I/O during the debugging process and it should be connected to the debugging probe. 

Serial Wire Debug

SWDIO

 pin is the clock used during the debugging process via SWD protocol and should be connected to the debugging probe. 

Raspberry Pi Pico Pinout

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