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304 lines
9.7 KiB
304 lines
9.7 KiB
.. _rpi_pico: |
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Raspberry Pi Pico |
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################# |
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Overview |
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******** |
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The Raspberry Pi Pico and Pico W are small, low-cost, versatile boards from |
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Raspberry Pi. They are equipped with an RP2040 SoC, an on-board LED, |
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a USB connector, and an SWD interface. The Pico W additionally contains an |
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Infineon CYW43439 2.4 GHz Wi-Fi/Bluetooth module. The USB bootloader allows the |
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ability to flash without any adapter, in a drag-and-drop manner. |
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It is also possible to flash and debug the boards with their SWD interface, |
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using an external adapter. |
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Hardware |
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- Dual core Arm Cortex-M0+ processor running up to 133MHz |
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- 264KB on-chip SRAM |
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- 2MB on-board QSPI flash with XIP capabilities |
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- 26 GPIO pins |
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- 3 Analog inputs |
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- 2 UART peripherals |
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- 2 SPI controllers |
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- 2 I2C controllers |
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- 16 PWM channels |
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- USB 1.1 controller (host/device) |
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- 8 Programmable I/O (PIO) for custom peripherals |
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- On-board LED |
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- 1 Watchdog timer peripheral |
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- Infineon CYW43439 2.4 GHz Wi-Fi chip (Pico W only) |
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.. figure:: img/rpi_pico.jpg |
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:align: center |
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:alt: Raspberry Pi Pico |
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.. figure:: img/rpi_pico_w.jpg |
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:align: center |
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:alt: Raspberry Pi Pico W |
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Raspberry Pi Pico (above) and Pico W (below) |
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(Images courtesy of Raspberry Pi) |
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Supported Features |
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================== |
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The rpi_pico board configuration supports the following |
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hardware features: |
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.. list-table:: |
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:header-rows: 1 |
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* - Peripheral |
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- Kconfig option |
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- Devicetree compatible |
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* - NVIC |
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- N/A |
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- :dtcompatible:`arm,v6m-nvic` |
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* - UART |
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- :kconfig:option:`CONFIG_SERIAL` |
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- :dtcompatible:`raspberrypi,pico-uart` |
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* - GPIO |
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- :kconfig:option:`CONFIG_GPIO` |
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- :dtcompatible:`raspberrypi,pico-gpio` |
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* - ADC |
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- :kconfig:option:`CONFIG_ADC` |
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- :dtcompatible:`raspberrypi,pico-adc` |
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* - I2C |
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- :kconfig:option:`CONFIG_I2C` |
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- :dtcompatible:`snps,designware-i2c` |
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* - SPI |
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- :kconfig:option:`CONFIG_SPI` |
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- :dtcompatible:`raspberrypi,pico-spi` |
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* - USB Device |
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- :kconfig:option:`CONFIG_USB_DEVICE_STACK` |
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- :dtcompatible:`raspberrypi,pico-usbd` |
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* - HWINFO |
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- :kconfig:option:`CONFIG_HWINFO` |
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- N/A |
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* - Watchdog Timer (WDT) |
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- :kconfig:option:`CONFIG_WATCHDOG` |
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- :dtcompatible:`raspberrypi,pico-watchdog` |
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* - PWM |
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- :kconfig:option:`CONFIG_PWM` |
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- :dtcompatible:`raspberrypi,pico-pwm` |
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* - Flash |
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- :kconfig:option:`CONFIG_FLASH` |
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- :dtcompatible:`raspberrypi,pico-flash` |
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* - Clock controller |
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- :kconfig:option:`CONFIG_CLOCK_CONTROL` |
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- :dtcompatible:`raspberrypi,pico-clock-controller` |
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* - UART (PIO) |
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- :kconfig:option:`CONFIG_SERIAL` |
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- :dtcompatible:`raspberrypi,pico-uart-pio` |
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* - SPI (PIO) |
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- :kconfig:option:`CONFIG_SPI` |
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- :dtcompatible:`raspberrypi,pico-spi-pio` |
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Pin Mapping |
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=========== |
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The peripherals of the RP2040 SoC can be routed to various pins on the board. |
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The configuration of these routes can be modified through DTS. Please refer to |
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the datasheet to see the possible routings for each peripheral. |
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External pin mapping on the Pico W is identical to the Pico, but note that internal |
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RP2040 GPIO lines 23, 24, 25, and 29 are routed to the Infineon module on the W. |
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Since GPIO 25 is routed to the on-board LED on the Pico, but to the Infineon module |
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on the Pico W, the "blinky" sample program does not work on the W (use hello_world for |
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a simple test program instead). |
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Default Zephyr Peripheral Mapping: |
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---------------------------------- |
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.. rst-class:: rst-columns |
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- UART0_TX : P0 |
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- UART0_RX : P1 |
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- I2C0_SDA : P4 |
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- I2C0_SCL : P5 |
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- I2C1_SDA : P6 |
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- I2C1_SCL : P7 |
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- SPI0_RX : P16 |
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- SPI0_CSN : P17 |
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- SPI0_SCK : P18 |
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- SPI0_TX : P19 |
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- ADC_CH0 : P26 |
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- ADC_CH1 : P27 |
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- ADC_CH2 : P28 |
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- ADC_CH3 : P29 |
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Programmable I/O (PIO) |
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********************** |
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The RP2040 SoC comes with two PIO periherals. These are two simple |
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co-processors that are designed for I/O operations. The PIOs run |
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a custom instruction set, generated from a custom assembly language. |
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PIO programs are assembled using :command:`pioasm`, a tool provided by Raspberry Pi. |
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Zephyr does not (currently) assemble PIO programs. Rather, they should be |
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manually assembled and embedded in source code. An example of how this is done |
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can be found at :zephyr_file:`drivers/serial/uart_rpi_pico_pio.c`. |
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Sample: SPI via PIO |
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==================== |
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The :zephyr_file:`samples/sensor/bme280/README.rst` sample includes a |
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demonstration of using the PIO SPI driver to communicate with an |
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environmental sensor. The PIO SPI driver supports using any |
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combination of GPIO pins for an SPI bus, as well as allowing up to |
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four independent SPI buses on a single board (using the two SPI |
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devices as well as both PIO devices). |
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Programming and Debugging |
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************************* |
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Flashing |
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======== |
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Using SEGGER JLink |
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------------------ |
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You can Flash the rpi_pico with a SEGGER JLink debug probe as described in |
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:ref:`Building, Flashing and Debugging <west-flashing>`. |
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Here is an example of building and flashing the :zephyr:code-sample:`blinky` application. |
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.. zephyr-app-commands:: |
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:zephyr-app: samples/basic/blinky |
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:board: rpi_pico |
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:goals: build |
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.. code-block:: bash |
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west flash --runner jlink |
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Using OpenOCD |
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------------- |
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To use CMSIS-DAP, You must configure **udev**. |
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Create a file in /etc/udev.rules.d with any name, and write the line below. |
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.. code-block:: bash |
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ATTRS{idVendor}=="2e8a", ATTRS{idProduct}=="000c", MODE="660", GROUP="plugdev", TAG+="uaccess" |
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This example is valid for the case that the user joins to ``plugdev`` groups. |
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The Raspberry Pi Pico has an SWD interface that can be used to program |
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and debug the on board RP2040. This interface can be utilized by OpenOCD. |
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To use it with the RP2040, OpenOCD version 0.12.0 or later is needed. |
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If you are using a Debian based system (including RaspberryPi OS, Ubuntu. and more), |
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using the `pico_setup.sh`_ script is a convenient way to set up the forked version of OpenOCD. |
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Depending on the interface used (such as JLink), you might need to |
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checkout to a branch that supports this interface, before proceeding. |
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Build and install OpenOCD as described in the README. |
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Here is an example of building and flashing the :zephyr:code-sample:`blinky` application. |
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.. zephyr-app-commands:: |
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:zephyr-app: samples/basic/blinky |
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:board: rpi_pico |
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:goals: build flash |
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:gen-args: -DOPENOCD=/usr/local/bin/openocd -DOPENOCD_DEFAULT_PATH=/usr/local/share/openocd/scripts -DRPI_PICO_DEBUG_ADAPTER=cmsis-dap |
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Set the environment variables **OPENOCD** to :file:`/usr/local/bin/openocd` |
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and **OPENOCD_DEFAULT_PATH** to :file:`/usr/local/share/openocd/scripts`. This should work |
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with the OpenOCD that was installed with the default configuration. |
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This configuration also works with an environment that is set up by the `pico_setup.sh`_ script. |
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**RPI_PICO_DEBUG_ADAPTER** specifies what debug adapter is used for debugging. |
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If **RPI_PICO_DEBUG_ADAPTER** was not assigned, ``cmsis-dap`` is used by default. |
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The other supported adapters are ``raspberrypi-swd``, ``jlink`` and ``blackmagicprobe``. |
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How to connect ``cmsis-dap`` and ``raspberrypi-swd`` is described in `Getting Started with Raspberry Pi Pico`_. |
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Any other SWD debug adapter maybe also work with this configuration. |
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The value of **RPI_PICO_DEBUG_ADAPTER** is cached, so it can be omitted from |
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``west flash`` and ``west debug`` if it was previously set while running |
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``west build``. |
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**RPI_PICO_DEBUG_ADAPTER** is used in an argument to OpenOCD as ``"source [find interface/${RPI_PICO_DEBUG_ADAPTER}.cfg]"``. |
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Thus, **RPI_PICO_DEBUG_ADAPTER** needs to be assigned the file name of the debug adapter. |
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You can also flash the board with the following |
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command that directly calls OpenOCD (assuming a SEGGER JLink adapter is used): |
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.. code-block:: console |
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$ openocd -f interface/jlink.cfg -c 'transport select swd' -f target/rp2040.cfg -c "adapter speed 2000" -c 'targets rp2040.core0' -c 'program path/to/zephyr.elf verify reset exit' |
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Using UF2 |
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--------- |
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If you don't have an SWD adapter, you can flash the Raspberry Pi Pico with |
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a UF2 file. By default, building an app for this board will generate a |
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:file:`build/zephyr/zephyr.uf2` file. If the Pico is powered on with the ``BOOTSEL`` |
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button pressed, it will appear on the host as a mass storage device. The |
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UF2 file should be drag-and-dropped to the device, which will flash the Pico. |
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Debugging |
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========= |
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The SWD interface can also be used to debug the board. To achieve this, you can |
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either use SEGGER JLink or OpenOCD. |
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Using SEGGER JLink |
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------------------ |
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Use a SEGGER JLink debug probe and follow the instruction in |
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:ref:`Building, Flashing and Debugging<west-debugging>`. |
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Using OpenOCD |
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------------- |
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Install OpenOCD as described for flashing the board. |
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Here is an example for debugging the :zephyr:code-sample:`blinky` application. |
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.. zephyr-app-commands:: |
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:zephyr-app: samples/basic/blinky |
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:board: rpi_pico |
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:maybe-skip-config: |
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:goals: debug |
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:gen-args: -DOPENOCD=/usr/local/bin/openocd -DOPENOCD_DEFAULT_PATH=/usr/local/share/openocd/scripts -DRPI_PICO_DEBUG_ADAPTER=raspberrypi-swd |
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As with flashing, you can specify the debug adapter by specifying **RPI_PICO_DEBUG_ADAPTER** |
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at ``west build`` time. No needs to specify it at ``west debug`` time. |
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You can also debug with OpenOCD and gdb launching from command-line. |
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Run the following command: |
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.. code-block:: console |
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$ openocd -f interface/jlink.cfg -c 'transport select swd' -f target/rp2040.cfg -c "adapter speed 2000" -c 'targets rp2040.core0' |
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On another terminal, run: |
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.. code-block:: console |
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$ gdb-multiarch |
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Inside gdb, run: |
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.. code-block:: console |
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(gdb) tar ext :3333 |
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(gdb) file path/to/zephyr.elf |
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You can then start debugging the board. |
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.. target-notes:: |
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.. _pico_setup.sh: |
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https://raw.githubusercontent.com/raspberrypi/pico-setup/master/pico_setup.sh |
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.. _Getting Started with Raspberry Pi Pico: |
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https://datasheets.raspberrypi.com/pico/getting-started-with-pico.pdf
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