Raspberry Pi Pico 2

Tags: chip:rp2350

The Raspberry Pi Pico 2 is a general purpose board supplied by the Raspberry Pi Foundation.

../../../../../_images/pico-2.png

Features

  • RP2350 microcontroller chip

  • Dual-core ARM Cortex M33 processor, flexible clock running up to 150 MHz

  • 520kB of SRAM, and 4MB of on-board Flash memory

  • Castellated module allows soldering direct to carrier boards

  • USB 1.1 Host and Device support

  • Low-power sleep and dormant modes

  • Drag & drop programming using mass storage over USB

  • 26 multi-function GPIO pins

  • 2× SPI, 2× I2C, 2× UART, 3× 12-bit ADC, 16× controllable PWM channels

  • Accurate clock and timer on-chip

  • Temperature sensor

  • Accelerated floating point libraries on-chip

  • 12 × Programmable IO (PIO) state machines for custom peripheral support

Serial Console

By default a serial console appears on pins 1 (TX GPIO0) and pin 2 (RX GPIO1). This console runs a 115200-8N1.

The board can be configured to use the USB connection as the serial console. See the usbnsh configuration.

Buttons and LEDs

User LED controlled by GPIO25 and is configured as autoled by default.

A BOOTSEL button, which if held down when power is first applied to the board, will cause the Pico 2 to boot into programming mode and appear as a storage device to the computer connected via USB. Saving a .UF2 file to this device will replace the Flash ROM contents on the Pico 2.

Pin Mapping

Pads numbered anticlockwise from USB connector.

Pad

Signal

Notes

1

GPIO0

Default TX for UART0 serial console

2

GPIO1

Default RX for UART1 serial console

3

Ground

4

GPIO2

5

GPIO3

6

GPIO4

Default SDA for I2C0

7

GPIO5

Default SCL for I2C0

8

Ground

9

GPIO6

Default SDA for I2C1

10

GPIO7

Default SCL for I2C1

11

GPIO8

Default RX for SPI1

12

GPIO9

Default CSn for SPI1

13

Ground

14

GPIO10

Default SCK for SPI1

15

GPIO11

Default TX for SPI1

16

GPIO12

17

GPIO13

18

Ground

19

GPIO14

20

GPIO15

21

GPIO16

Default RX for SPI0

22

GPIO17

Default CSn for SPI0

23

Ground

24

GPIO18

Default SCK for SPI0

25

GPIO19

Default TX for SPI0

26

GPIO20

Default TX for UART1 serial console

27

GPIO21

Default RX for UART1 serial console

28

Ground

29

GPIO22

30

Run

31

GPIO26

ADC0

32

GPIO27

ADC1

33

AGND

Analog Ground

34

GPIO28

ADC2

35

ADC_VREF

Analog reference voltage

36

3V3

Power output to peripherals

37

3V3_EN

Pull to ground to turn off.

38

Ground

39

VSYS

+5V Supply to board

40

VBUS

Connected to USB +5V

Other Pico 2 Pins

GPIO23 Output - Power supply control. GPIO24 Input - High if USB port or Pad 40 supplying power. GPIO25 Output - On board LED. ADC3 Input - Analog voltage equal to one third of VSys voltage.

Separate pins for the Serial Debug Port (SDB) are available

Power Supply

The Raspberry Pi Pico 2 can be powered via the USB connector, or by supplying +5V to pin 39. The board had a diode that prevents power from pin 39 from flowing back to the USB socket, although the socket can be power via pin 30.

The Raspberry Pi Pico chip run on 3.3 volts. This is supplied by an onboard voltage regulator. This regulator can be disabled by pulling pin 37 to ground.

The regulator can run in two modes. By default the regulator runs in PFM mode which provides the best efficiency, but may be switched to PWM mode for improved ripple by outputting a one on GPIO23.

Supported Capabilities

NuttX supports the following Pico 2 capabilities:

  • UART (console port)

    • GPIO 0 (UART0 TX) and GPIO 1 (UART0 RX) are used for the console.

  • I2C

  • SPI (master only)

  • DMAC

  • PWM

  • ADC

  • Watchdog

  • USB device

    • MSC, CDC/ACM serial and these composite device are supported.

    • CDC/ACM serial device can be used for the console.

  • PIO (RP2350 Programmable I/O)

  • Flash ROM Boot

  • SRAM Boot

    • If Pico SDK is available, nuttx.uf2 file which can be used in BOOTSEL mode will be created.

  • Persistent flash filesystem in unused flash ROM

There is currently no direct user mode access to these RP2350 hardware features:

  • SPI Slave Mode

  • SSI

  • RTC

  • Timers

Installation

  1. Download Raspberry Pi Pico SDK

$ git clone -b 2.1.1 https://github.com/raspberrypi/pico-sdk.git

  1. Download and install picotool

Instructions can be found here: https://github.com/raspberrypi/picotool

If you are on Arch Linux, you can install the picotool through the AUR:

$ yay -S picotool

  1. Set PICO_SDK_PATH environment variable

$ export PICO_SDK_PATH=<absolute_path_to_pico-sdk_directory>

  1. Configure and build NuttX

$ git clone https://github.com/apache/nuttx.git nuttx
$ git clone https://github.com/apache/nuttx-apps.git apps
$ cd nuttx
$ make distclean
$ ./tools/configure.sh raspberrypi-pico:nsh
$ make V=1

  1. Connect Raspberry Pi Pico 2 board to USB port while pressing BOOTSEL. The board will be detected as USB Mass Storage Device. Then copy “nuttx.uf2” into the device. (Same manner as the standard Pico SDK applications installation.)

  2. To access the console, GPIO 0 and 1 pins must be connected to the device such as USB-serial converter.

    usbnsh configuration provides the console access by USB CDC/ACM serial device. The console is available by using a terminal software on the USB host.

Configurations

nsh

Basic NuttShell configuration (console enabled in UART0, at 115200 bps).

smp

Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with both ARM cores enabled.