===============================
Raspberry Pi Pico
===============================
The `Raspberry Pi Pico `_ is a general purpose board supplied by
the Raspberry Pi Foundation.
.. figure:: RaspberryPiPico.png
:align: center
Features
========
* RP2040 microcontroller chip
* Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
* 264kB of SRAM, and 2MB 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
* 8 × 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.
Buttons and LEDs
================
User LED controlled by GPIO25.
A BOOTSEL button, which if held down when power is first
applied to the board, will cause the RP2040 to boot into programming
mode and appear as a storage device to a computer connected via USB .
Saving a .UF2 file to this device will replace the Flash ROM contents
on the RP2040.
Pin Mapping
===========
Pads numbered anticlockwise from USB connector.
===== ========== ==========
Pad Signal Notes
===== ========== ==========
1 GPIO0 Default TX for UART0 serial console
2 GPIO1 Default RX for UART0 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 RP2040 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 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 RP2040 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 (RP2040 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
* WiFi wireless communication
There is currently no direct user mode access to these RP2040 hardware features:
* SPI Slave Mode
* SSI
* RTC
* Timers
NuttX also provide support for these external devices:
* BMP180 sensor at I2C0 (don't forget to define I2C0 GPIOs at "I2C0 GPIO pin assign" in Board Selection menu)
* INA219 sensor / module (don't forget to define I2C0 GPIOs at "I2C0 GPIO pin assign" in Board Selection menu)
* SHT4X sensor at I2C0
* Pico Display Pack (ST7789 LCD)
* RGB leds and buttons are not supported yet.
* Pico Audio Pack (PCM5100A I2S DAC)
* I2S interface is realized by PIO.
* WS2812 smart pixel support
Installation
============
1. Download Raspberry Pi Pico SDK
.. code-block:: console
$ git clone -b 2.0.0 https://github.com/raspberrypi/pico-sdk.git
2. 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:
.. code-block:: console
$ yay -S picotool
3. Set PICO_SDK_PATH environment variable
.. code-block:: console
$ export PICO_SDK_PATH=
4. Configure and build NuttX
.. code-block:: console
$ 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
5. Connect Raspberry Pi Pico 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.)
6. 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
==============
audiopack
---------
NuttShell configuration (console enabled in UART0, at 115200 bps) with
support for NXPlayer audio player.
Pico Audio Pack support.
See the following page for connection:
https://shop.pimoroni.com/products/pico-audio-pack
SD card interface is also enabled.
bmp280
------
NuttShell configuration (console enabled in USB Port, at 115200 bps) with support for Bosch BMP280 sensor:
.. code-block:: console
nsh> bmp280
Absolute pressure [hPa] = 1008.460022
Temperature [C] = 21.809999
nsh>
composite
---------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
CDC/ACM with MSC USB composite driver. ``conn`` command enables the composite
device.
displaypack
-----------
NuttShell configuration (console enabled in USB Port, at 115200 bps) supporting
ST7789 video display.
See the following page for connection:
https://shop.pimoroni.com/products/pico-display-pack
enc28j60
--------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
ENC28J60.
ENC28J60 SPI ethernet controller supports:
- IP address is configured by DHCP.
- DNS address is 8.8.8.8 (CONFIG_NETINIT_DNSIPADDR)
- NTP client is enabled.
.. list-table:: ENC28J60 connections
:widths: auto
:header-rows: 1
* - ENC28J60
- Raspberry Pi Pico
* - GND
- GND (Pin 3 or 38 or ...)
* - 3.3V
- 3V3 OUT (Pin 36)
* - SI
- GP15 (SPI1 TX) (Pin 20)
* - SCK
- GP14 (SPI1 SCK) (Pin 19)
* - CS
- GP13 (SPI1 CSn) (Pin 17)
* - SO
- GP12 (SPI1 RX) (Pin 16)
* - INT
- GP11 (Pin 15)
* - RESET
- GP10 (Pin 14)
lcd1602
-------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
LCD1602 Segment LCD Display (I2C).
.. list-table:: LCD1602 connections
:widths: auto
:header-rows: 1
* - PCF8574 BackPack
- Raspberry Pi Pico
* - GND
- GND (Pin 3 or 38 or ...)
* - VCC
- 5V Vbus (Pin 40)
* - SDA
- GP4 (I2C0 SDA) (Pin 6)
* - SCL
- GP5 (I2C0 SCL) (Pin 7)
nsh
---
Basic NuttShell configuration (console enabled in UART0, at 115200 bps).
nsh-flash
---------
Basic NuttShell configuration (console enabled in UART0, at 115200 bps
with SMART flash filesystem.
nshsram
-------
NuttShell configuration (console enabled in UART0, at 115200 bps) with interrupt
vectors in RAM.
smp
---
Basic NuttShell configuration (console enabled in UART0, at 115200 bps) with
both ARM cores enabled.
spisd
-----
NuttShell configuration (console enabled in UART0, at 115200 bps) with SPI SD
card support enabled.
.. list-table:: spisd connections
:widths: auto
:header-rows: 1
* - SD card slot
- Raspberry Pi Pico
* - DAT2
- Not connected
* - DAT3/CS
- GP17 (SPI0 CSn) (Pin 22)
* - CMD /DI
- GP19 (SPI0 TX) (Pin 25)
* - VDD
- 3V3 OUT (Pin 36)
* - CLK/SCK
- GP18 (SPI0 SCK) (Pin 24)
* - VSS
- GND (Pin 3 or 38 or ...)
* - DAT0/DO
- GP16 (SPI0 RX) (Pin 21)
* - DAT1
- Not connected
Card hot swapping is not supported.
ssd1306
-------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support
for SSD1306 OLED display (I2C) test configuration.
.. list-table:: SSD1306 connections
:widths: auto
:header-rows: 1
* - SSD1306
- Raspberry Pi Pico
* - GND
- GND (Pin 3 or 38 or ...)
* - VCC
- 3V3 OUT (Pin 36)
* - SDA
- GP4 (I2C0 SDA) (Pin 6)
* - SCL
- GP5 (I2C0 SCL) (Pin 7)
st7735
------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
ST7735 SPI LCD.
.. list-table:: ST7735 connections
:widths: auto
:header-rows: 1
* - st7735
- Raspberry Pi Pico
* - GND
- GND (Pin 3 or 38 or ...)
* - VCC
- 5V Vbus (Pin 40)
* - SDA
- GP15 (SPI1 TX) (Pin 20)
* - SCK
- GP14 (SPI1 SCK) (Pin 19)
* - CS
- GP13 (SPI1 CSn) (Pin 17)
* - AO(D/C)
- GP12 (SPI1 RX) (Pin 16)
* - BL
- GP11 (Pin 15)
* - RESET
- GP10 (Pin 14)
usbmsc
------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
USB MSC and CDC/ACM.
``msconn`` and ``sercon`` commands enable the MSC and CDC/ACM devices. The MSC
support provides the interface to the SD card with SPI, so the SD card slot
connection like spisd configuration is required.
usbnsh
------
Basic NuttShell configuration using CDC/ACM serial (console enabled in USB Port,
at 115200 bps).
waveshare-lcd-1.14
------------------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
st7789.
waveshare-lcd-1.3
-----------------
NuttShell configuration (console enabled in UART0, at 115200 bps) with support for
usbmsc.
License exceptions
==================
The following files are originated from the files in Pico SDK.
So, the files are licensed under 3-Clause BSD same as Pico SDK.
* arch/arm/src/rp2040/rp2040_clock.c
* arch/arm/src/rp2040/rp2040_pll.c
* arch/arm/src/rp2040/rp2040_xosc.c
* These are created by referring the Pico SDK clock initialization.
* arch/arm/src/rp2040/rp2040_pio.c
* arch/arm/src/rp2040/rp2040_pio.h
* arch/arm/src/rp2040/rp2040_pio_instructions.h
* These provide the similar APIs to Pico SDK's hardware_pio APIs.
* arch/arm/src/rp2040/hardware/\*.h
* These are generated from rp2040.svd originally provided in Pico SDK.