Minimal bring-up project for ATSAMV71Q21B

This repository contains all necessary components to start developing software for the ATSAMV71Q21B MCU, using the Harmony 3 framework.

Features

• Cross-platform: Builds work consistently out of the box on Windows and Linux.
• Reliable: No machine-specific configuration required for new dev setups.
• Standards-focused: Built around standard tools (ARM GCC, CMake and Conan 2).
• IDE-agnostic: Works on any CMake-supporting IDE, as well as the terminal.
• Version-controllable: Dependency tracking is conducted by Conan, even for Harmony tools and components, allowing for consistent builds anywhere.
• Fully integrated: Harmony configuration (MHC) is entirely controlled from within CMake, both for the UI and for codegen. Generated components are mapped to modern CMake targets.
• Tooling-agnostic: Vendor-specific tools are isolated and can always be removed at any time with minimal disruption.
• Documented: All settings and scripts come with detailed explanations of purpose.

Quick Start

Ensure that you have these tools installed and on your PATH before you start.

Tool	Version
ARM GCC (arm-none-eabi-gcc --version)	13.3
CMake (cmake --version)	3.30.1
Ninja (ninja --version)	1.12.1
Conan (conan -v)	2.5.0
OpenOCD (openocd -v)	0.12.0
Adoptium OpenJDK (java -version)	>= 8

Download OpenJDK from https://adoptium.net

To verify if they are on PATH:

• Windows: open Command Prompt (cmd.exe),
• Linux: open Terminal,

type the command in parentheses on the table and hit Enter. Do this for each tool. You should get text indicating the version somewhere. If you get an error (not found) then look here for how to set up your PATH correctly.

Step 0: Clone this repository

Step 1: Install the Conan profile for SAMV71

All commands are run from the root directory. Assuming you have set up a default Conan profile (with conan profile detect), run:

conan config install ./conan/config/

This will add a new Conan profile, named baremetal-samv71-armv7. The profile includes global compiler and CMake settings necessary for building working code for the SAMV71 platform. From now on, pass the profile's name (-pr=baremetal-samv71-armv7) whenever interacting with conan. Refer to the config's README file for more information.

Step 2: Install the Harmony Conan packages

Manual installation

Harmony consists of a set of interdependent components, which are individually packaged for version control purposes. Install each of them with the following command:

conan create ./conan/recipes/<package-name> -pr=baremetal-samv71-armv7

where package-name is the package's directory name. The correct order for installation (higher on the list = first):

cmsis
samv71-dfp
harmony-csp
harmony-mhc
harmony

Deviating from this order will just cause Conan to throw an error of missing dependencies. The process is completely automated; see ./conan/recipes/<package-name>/conanfile.py for configuration details of each package.

Install from Artifactory

TODO.

Usage

Setting up a new project

Create a new conanfile.py:

from conan import ConanFile
from conan.tools.cmake import CMake, cmake_layout


class my_samv71_projectRecipe(ConanFile):
    name = "my-samv71-project"
    version = "1.0"
    package_type = "application"
    requires = "samv71-dfp/4.9.117"
    settings = "build_type", "arch"
    generators = "CMakeToolchain", "CMakeDeps"

    # Sources are located in the same place as this recipe, copy them to the recipe
    exports_sources = "CMakeLists.txt", "src/*"

    def layout(self):
        cmake_layout(self)

    def build(self):
        cmake = CMake(self)
        cmake.configure()
        cmake.build()

    def package(self):
        cmake = CMake(self)
        cmake.install()

This is just a minimal Conan skeleton, with a declared dependency on the DFP, which is essential for making anything work on the SAMV71 and you'll be using it all the time. Refer to Conan docs for details on how to make Conanfiles.

Create a new CMakeLists.txt in your project dir:

cmake_minimum_required(VERSION 3.30)
project(my-samv71-project LANGUAGES C CXX)

find_package(SAMV71-DFP COMPONENTS SAMV71Q21B REQUIRED)

add_executable(my-samv71-project src/main.cpp)

target_link_libraries(my-samv71-project PRIVATE samv71-dfp::Core samv71-dfp::SAMV71Q21B::Startup samv71-dfp::SAMV71Q21B::Linker::Flash)

NOTE: Always link a startup file and linker script in the final binary (either the ones from the DFP used here, or your own with target_link_options(my-samv71-project PRIVATE "-T/your/script.ld")). Otherwise you will get linker errors such as undefined symbol '_sbss' referenced in expression which are defined in the startup files.

Create a source file (src/main.cpp):

int main() {
    while (true) {

    }
}

Build the project:

conan build . -pr=baremetal-samv71-armv7

The resulting binary should be at build/Debug/my-samv71-project.elf

Using Harmony

conanfile.py: Add "harmony/3.0" in your requires line, as follows:

requires = "samv71-dfp/4.9.117", "harmony/3.0"

NOTE: Every time you modify your conanfile.py, you have to rerun conan build . -pr=baremetal-samv71-armv7 in order for CMake to be updated with the freshest dependency info.

CMakeLists.txt:

find_package(Harmony REQUIRED)

Configuring the MCU

NOTE: This will be available only after you have enabled Harmony.

The Harmony setup includes the Microchip Harmony Configurator (MHC) tool for adjusting settings and generating peripheral drivers. MHC needs Java installed and in your PATH to work. If your Java setting is incorrect, CMake will notify you with an error.

To launch it, use

cd build/Debug \
ninja mcu_config

This MHC instance is under the control of CMake, and can only be used by issuing this command.

To create a new configuration, follow exactly this workflow:

1. Click File -> New Configuration. Even if editing existing settings, always create a new configuration.
2. No need to set Location/Project Name/Configuration Name, they don't really matter in this case.
3. Select ATSAMV71Q21B under Target Device. The supporting files for other devices are missing and thus will not work. Make sure this is correct; otherwise you have to start the process all over.
4. Click Finish. On the Configuration Database Setup click Launch.
5. Configure away.
6. Click File -> Save Configuration (the disk icon), then File -> Export. At the Export dialog, check all checkboxes and specify a folder where you'll get your settings. Always save before exporting, otherwise you won't get files back.

To edit an existing configuration, follow Steps 1-4, then click File -> Import and specify the directory of your exported configuration files. When done, save and export back.

CAUTION: Do NOT use the code generation feature, it will not work and cause MHC to hang. Generation will be done automatically by CMake whenever needed, see this section.

Generating peripheral driver code

NOTE: This will be available only after you have enabled Harmony.

The Harmony package includes a helper script for MHC, which can be found under ./conan/recipes/harmony/cmake/MHCHelper.cmake. This script is implicitly included after calling find_package(Harmony) and generates the code using MHC at configure time.

In your CMakeLists.txt, add this:

add_harmony_config(
        MCU_MODEL ATSAMV71Q21B
        YAML_FILES <list of MHC-exported yml files>
)

You can use the generated code by linking in your executable the targets:

• Harmony::PeripheralDrivers: generated peripheral drivers.
• Harmony::Interrupts : interrupt handler code
• Harmony::SysInit: the SYS_Initialize() function that does the clock init.

Uploading code

You can upload compiled .elf binaries using OpenOCD and a suitable configuration file (e.g. atmel_samv71_xplained_ultra.cfg for the Atmel SAMV71 Xplained Ultra board) with the following command:

openocd -f /path/to/cfg/file -c "program /path/to/compiled/binary.elf reset"

Attaching a debugger

OpenOCD automatically opens a debug server to which you can connect using GDB if needed, as follows:

arm-none-eabi-gdb /path/to/compiled/binary_with_symbols.elf

Within GDB, run the following command to connect: target extended-remote localhost:3333

CLion integration

Many developers in the team prefer using CLion for day-to-day coding. Conan generates CMake presets, which can be used for setting up CLion run configurations as follows:

1. Generate CMake toolchains for Debug and Release builds using:

• conan install . -pr=baremetal-samv71-armv7 -s build_type=Debug
• conan install . -pr=baremetal-samv71-armv7 -s build_type=Release This should have generated a CMakeUserPresets.json file in the project directory.

2. Start CLion and open the project directory (Open button).
3. CLion should pop up a message in the lower right corner stating Loaded XXXX CMake presets and a window named Open Project Wizard.
4. In the Open Project Wizard, disable the default Debug profile by unticking the Enable profile checkbox. Enable only the conan-debug and conan-release profiles.
5. Click OK. You should now have two options for conan-debug and conan-release, so you can switch between them at will.
6. Add an OpenOCD run configuration via Run -> Edit Configurations. Click the + button on the upper left corner and select OpenOCD Download and Run from the list.
7. Set the Executable binary to your project's binary target, the Debugger to arm-none-eabi-gdb and the Board config file to OpenOCD's cfg file. Leave the rest of the settings at default.
8. Click OK.

If everything went well, add a random breakpoint in your code (make sure it's actually reachable) and try running the debugger from the "bug" icon. CLion should build, upload and attach automatically, and when the breakpoint is hit CLion's debug interface will start up, letting you step as always.

Appendix: Conan package description

Device Family Pack (DFP)

Description

The DFP (packaged as samv71-dfp) is the most important component to include in any SAMV71 project. It contains:

• headers describing the register layout of all SAMV71 devices
• startup code (default Reset_Handler and interrupt vector table)
• default linker scripts (program code layout)

Usage

Add samv71-dfp/4.9.117 to your conanfile.py. Then, from your CMakeLists.txt use:

find_package(SAMV71-DFP COMPONENTS SAMV71Q21B REQUIRED)
# ...

Note that all devices are included, just change the COMPONENT name if so desired. Publicly available targets (via target_link_libraries):

samv71-df::Core (headers for all devices)
samv71-dfp::SAMV71Q21B::Startup (default startup file)
samv71-dfp::SAMV71Q21B::Linker::Flash (default linker script for booting via NAND)
samv71-dfp::SAMV71Q21B::Linker::SRAM (default linker script for booting via SRAM)

Chip Support Pack (CSP)

TODO

Microchip Harmony Configurator (MHC)

TODO

Examples

The repository includes example code under examples/. Refer to each example's README files for details.