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Flash & Debug Host Tools

This guide describes the software tools you can run on your host workstation to flash and debug Zephyr applications.

Zephyr’s west tool has built-in support for all of these in its flash, debug, debugserver, and attach commands, provided your board hardware supports them and your Zephyr board directory’s board.cmake file declares that support properly. See Building, Flashing and Debugging for more information on these commands.

SAM Boot Assistant (SAM-BA)

Atmel SAM Boot Assistant (Atmel SAM-BA) allows In-System Programming (ISP) from USB or UART host without any external programming interface. Zephyr allows users to develop and program boards with SAM-BA support using west. Zephyr supports devices with/without ROM bootloader and both extensions from Arduino and Adafruit. Full support was introduced in Zephyr SDK 0.12.0.

The typical command to flash the board is:

west flash [ -r bossac ] [ -p /dev/ttyX ]

Flash configuration for devices:

These devices don’t need any special configuration. After building your application, just run west flash to flash the board.

Note

The CONFIG_BOOTLOADER_BOSSA_LEGACY Kconfig option should be used as last resource. Try configure first with Devices without ROM bootloader.

Typical flash layout and configuration

For bootloaders that reside on flash, the devicetree partition layout is mandatory. For devices that have a ROM bootloader, they are mandatory when the application uses a storage or other non-application partition. In this special case, the boot partition should be omitted and code_partition should start from offset 0. It is necessary to define the partitions with sizes that avoid overlaps, always.

A typical flash layout for devices without a ROM bootloader is:

/ {
        chosen {
                zephyr,code-partition = &code_partition;
        };
};

&flash0 {
        partitions {
                compatible = "fixed-partitions";
                #address-cells = <1>;
                #size-cells = <1>;

                boot_partition: partition@0 {
                        label = "sam-ba";
                        reg = <0x00000000 0x2000>;
                        read-only;
                };

                code_partition: partition@2000 {
                        label = "code";
                        reg = <0x2000 0x3a000>;
                        read-only;
                };

                /*
                * The final 16 KiB is reserved for the application.
                * Storage partition will be used by FCB/LittleFS/NVS
                * if enabled.
                */
                storage_partition: partition@3c000 {
                        label = "storage";
                        reg = <0x0003c000 0x00004000>;
                };
        };
};

A typical flash layout for devices with a ROM bootloader and storage partition is:

/ {
        chosen {
                zephyr,code-partition = &code_partition;
        };
};

&flash0 {
        partitions {
                compatible = "fixed-partitions";
                #address-cells = <1>;
                #size-cells = <1>;

                code_partition: partition@0 {
                        label = "code";
                        reg = <0x0 0xF0000>;
                        read-only;
                };

                /*
                * The final 64 KiB is reserved for the application.
                * Storage partition will be used by FCB/LittleFS/NVS
                * if enabled.
                */
                storage_partition: partition@F0000 {
                        label = "storage";
                        reg = <0x000F0000 0x00100000>;
                };
        };
};

Enabling SAM-BA runner

In order to instruct Zephyr west tool to use the SAM-BA bootloader the board.cmake file must have include(${ZEPHYR_BASE}/boards/common/bossac.board.cmake) entry. Note that Zephyr tool accept more entries to define multiple runners. By default, the first one will be selected when using west flash command. The remaining options are available passing the runner option, for instance west flash -r bossac.

More implementation details can be found in the Supported Boards documentation. As a quick reference, see these three board documentation pages:

Enabling BOSSAC on Windows Native [Experimental]

Zephyr SDK´s bossac is currently supported on Linux and macOS only. Windows support can be achieved by using the bossac version from BOSSA official releases. After installing using default options, the bossac.exe must be added to Windows PATH. A specific bossac executable can be used by passing the --bossac option, as follows:

west flash -r bossac --bossac="C:\Program Files (x86)\BOSSA\bossac.exe" --bossac-port="COMx"

Note

WSL is not currently supported.

LinkServer Debug Host Tools

Linkserver is a utility for launching and managing GDB servers for NXP debug probes, which also provides a command-line target flash programming capabilities. Linkserver can be used with the NXP MCUXpresso for Visual Studio Code implementation, with custom debug configurations based on GNU tools or as part of a headless solution for continuous integration and test. LinkServer can be used with MCU-Link, LPC-Link2, LPC11U35-based and OpenSDA based standalone or on-board debug probes from NXP.

NXP recommends installing LinkServer by using NXP’s MCUXpresso Installer. This method will also install the tools supporting the debug probes below, including NXP’s MCU-Link and LPCScrypt tools.

LinkServer is compatible with the following debug probes:

To use LinkServer with West commands, the install folder should be added to the PATH environment variable. The default installation path to add is:

/usr/local/LinkServer

Supported west commands:

  1. flash

  2. debug

  3. debugserver

  4. attach

Notes:

  1. Probes can be listed with LinkServer:

LinkServer probes

2. With multiple debug probes attached to the host, use the LinkServer west runner --probe option to pass the probe index.

west flash --runner=linkserver --probe=3

  1. Device-specific settings can be overridden with the west runner for LinkServer with the option ‘–override’. May be used multiple times. The format is dictated by LinkServer, e.g.:

west flash --runner=linkserver --override /device/memory/5/flash-driver=MIMXRT500_SFDP_MXIC_OSPI_S.cfx

  1. LinkServer does not install an implicit breakpoint at the reset handler. If you would like to single step from the start of their application, you will need to add a breakpoint at main or the reset handler manually.

OpenOCD Debug Host Tools

OpenOCD is a community open source project that provides GDB remote debugging and flash programming support for a wide range of SoCs. A fork that adds Zephyr RTOS-awareness is included in the Zephyr SDK; otherwise see Getting OpenOCD for options to download OpenOCD from official repositories.

These debug host tools are compatible with the following debug probes:

Check if your SoC is listed in OpenOCD Supported Devices.

Note

On Linux, openocd is available though the Zephyr SDK. Windows users should use the following steps to install openocd:

  • Download openocd for Windows from here: OpenOCD Windows

  • Copy bin and share dirs to C:\Program Files\OpenOCD\

  • Add C:\Program Files\OpenOCD\bin to ‘PATH’ environment variable

pyOCD Debug Host Tools

pyOCD is an open source project from Arm that provides GDB remote debugging and flash programming support for Arm Cortex-M SoCs. It is distributed on PyPi and installed when you complete the Get Zephyr and install Python dependencies step in the Getting Started Guide. pyOCD includes support for Zephyr RTOS-awareness.

These debug host tools are compatible with the following debug probes:

Check if your SoC is listed in pyOCD Supported Devices.

Lauterbach TRACE32 Debug Host Tools

Lauterbach TRACE32 is a product line of microprocessor development tools, debuggers and real-time tracer with support for JTAG, SWD, NEXUS or ETM over multiple core architectures, including Arm Cortex-A/-R/-M, RISC-V, Xtensa, etc. Zephyr allows users to develop and program boards with Lauterbach TRACE32 support using west.

The runner consists of a wrapper around TRACE32 software, and allows a Zephyr board to execute a custom start-up script (Practice Script) for the different commands supported, including the ability to pass extra arguments from CMake. Is up to the board using this runner to define the actions performed on each command.

Install Lauterbach TRACE32 Software

Download Lauterbach TRACE32 software from the Lauterbach TRACE32 download website (registration required) and follow the installation steps described in Lauterbach TRACE32 Installation Guide.

Flashing and Debugging

Set the environment variable T32_DIR to the TRACE32 system directory. Then execute west flash or west debug commands to flash or debug the Zephyr application as detailed in Building, Flashing and Debugging. The debug command launches TRACE32 GUI to allow debug the Zephyr application, while the flash command hides the GUI and perform all operations in the background.

By default, the t32 runner will launch TRACE32 using the default configuration file named config.t32 located in the TRACE32 system directory. To use a different configuration file, supply the argument --config CONFIG to the runner, for example:

west flash --config myconfig.t32

For more options, run west flash --context -r t32 to print the usage.

Zephyr RTOS Awareness

To enable Zephyr RTOS awareness follow the steps described in Lauterbach TRACE32 Zephyr OS Awareness Manual.

NXP S32 Debug Probe Host Tools

NXP S32 Debug Probe is designed to work in conjunction with NXP S32 Design Studio for S32 Platform.

Download (registration required) NXP S32 Design Studio for S32 Platform and follow the S32 Design Studio for S32 Platform Installation User Guide to get the necessary debug host tools and associated USB device drivers.

Note that Zephyr RTOS-awareness support for the NXP S32 GDB server depends on the target device. Consult the product release notes for more information.

Supported west commands:

  1. debug

  2. debugserver

  3. attach

Basic usage

Before starting, add NXP S32 Design Studio installation directory to the system PATH environment variable. Alternatively, it can be passed to the runner on each invocation via --s32ds-path as shown below:

west debug --s32ds-path=/opt/NXP/S32DS.3.5

If multiple S32 debug probes are connected to the host via USB, the runner will ask the user to select one via command line prompt before continuing. The connection string for the probe can be also specified when invoking the runner via --dev-id=<connection-string>. Consult NXP S32 debug probe user manual for details on how to construct the connection string. For example, if using a probe with serial ID 00:04:9f:00:ca:fe:

west debug --dev-id='s32dbg:00:04:9f:00:ca:fe'

It is possible to pass extra options to the debug host tools via --tool-opt. When executing debug or attach commands, the tool options will be passed to the GDB client only. When executing debugserver, the tool options will be passed to the GDB server. For example, to load a Zephyr application to SRAM and afterwards detach the debug session:

west debug --tool-opt='--batch'