PVDXos

The real-time operating system for Brown Space Engineering’s second satellite, Perovskite Visuals and Degredation eXperiment (PVDX).

Project Setup and Toolchain Installation Guide

Building and Running:

Note: If you’re using a factory-new devboard that you’ve just unboxed, please follow these instructions first before continuing. If you’ve received a working devboard from another team member, you can continue.

1. Start the SEGGER GDB Server:

   • run JLinkGDBServer from the SEGGER folder containing all the J-Link tools.
   • Before clicking ‘OK’, make sure the target is set to ATSAMD51P20A, and the interface is set to SWD
   • WINDOWS/WSL ONLY: The “Localhost Only” checkbox must be unchecked.
   • Ensure the J-Link server is on port 2331 for GDB connections.

2. Build the Project:

   • Execute make to build the project.

3. Flash the Bootloader:

   • If you’re using a brand-new devboard, you must flash the bootloader. This is done by running make flash_bootloader. Once GDB starts up successfully, you can exit gdb.
   • If you’re using a devboard that has already been set up, you can usually skip this step, but it never hurts!
   • If/When the bootloader gets an update, you can update it by running make flash_bootloader again.

4. Connect and Run:

   • Use make connect to connect to the board and auto-flash/run the program.
   • The code will automatically pause at the top of the ‘main’ function. Set any breakpoints you need, and then continue running the program with ‘c’
   • To connect to the PVDXos Shell, use Telnet to establish a connection to localhost:19021. You can use PuTTY for this on Windows, or nc localhost 19021 to connect with netcat on a Mac/Linux terminal
   • If using PuTTY, go to ‘Terminal’ and check the box for ‘Implicit CR in every LF’ so that line endings work correctly
   • Log output can be viewed by running python3 scripts/rtt_logs.py in a separate terminal window. This will also record logs to the /logs folder.
   • If the script fails to run, you may need to install ‘pylink-square’ (pip install pylink-square)
   • Alternatively, you can try running python3 scripts/rtt_splitscreen.py for both the PVDXos Shell and log output in the same terminal window, but this might not work!

Toolchain Installation

All Platforms (Initial Step)

• Download Segger’s J-Link tools from here.

Windows

1. Install Windows Subsystem for Linux (WSL):

   • Run wsl --install in PowerShell (as Administrator).
   • Follow prompts and restart your computer as required.

2. Clone the repository into the WSL filesystem. This is important for performance during compilation.

3. Install ARM toolchain for Linux:

   • sudo apt install gcc-arm-none-eabi

4. Install GDB Multiarch and other build tools:

   • sudo apt install gdb-multiarch
   • sudo apt install build-essential
   • sudo apt install clang-format

5. (Optional) Configure VSCode to use clang-format for formatting:

   • Install the clang-format extension in VSCode.
   • In VSCode properties, set the default formatter to clang-format.
   • Enable ‘format on save’ in the settings.
   • Set ‘format on save mode’ to ‘modifications’.

Mac/Linux (Geared towards Mac)

Note: Skip to step 5 if you have a Mac with an Intel processor.

1. Edit the ~/.zshrc file:

   • You can use nano ~/.zshrc to edit this file. Use CTRL+X, then Y, then Enter to quit and save.
   • Add these lines to the bottom of the file:

     alias arm="env /usr/bin/arch -arm64 /bin/zsh --login"
     alias intel="env /usr/bin/arch -x86_64 /bin/zsh --login"

2. Run source ~/.zshrc.

   • This should enable the arm and intel commands in your terminal. Test this out by running intel and checking that the result of running arch is i386. Then run arm and check that the result of arch is arm64.

3. Switch into an intel terminal by running the intel command you just created, and verify that the arch command returns i386

4. Install brew in the intel terminal by running the script at https://brew.sh/ and following the prompts

   • Note: After the Brew installation is complete, it will prompt you to run two other commands. Remember to copy/paste them into the terminal and run these as well.

5. Install gdb:

   • brew install gdb

6. Download Arm Developer Tools:

   • Download & Install the .pkg from here.
   • Make sure you’re downloading for the right hardware.

7. Add the Arm Developer Tools to your path by adding the following line to the bottom of the ~/.zshrc (or ~/.bash_profile) file, similar to step 1

   • Add:

     export PATH="/Applications/ArmGNUToolchain/<VersionNumber>/arm-none-eabi/bin/:$PATH"

   • IMPORTANT: Remember to replace <VersionNumber> with the version number of the toolchain you downloaded. It should be something like ‘13.2.Rel1’

8. Install other build tools:

   • brew install gnu-sed (if on mac)
   • brew install clang-format

9. (Optional) Configure VSCode to use clang-format for formatting:

   • Install the clang-format extension in VSCode.
   • In VSCode properties, set the default formatter to clang-format.
   • Enable ‘format on save’ in the settings.
   • Set ‘format on save mode’ to ‘modifications’.

---

Setting Up a Brand New Metro M4 Grand Central Devboard

The Grand Central runs on an Atmel SAMD51P20A, which has a BOOTPROT fuse protecting the flash area of the bootloader. If you have a factory-new board, you will need to clear the BOOTPROT fuse to allow your J-Link to flash code onto the board.

1. Install and open Microchip Studio.

   Note: Microchip Studio only supports Windows, so you might have to use a friend’s computer for this, or in the worst case, install a Windows VM.

2. Connect your M4 Grand Central and J-Link to your computer via USB (and make sure they’re connected to each other).
3. In Microchip Studio, go to Tools > Device Programming.
   • In the dialog that opens, select Tool > J-Link, Device > ATSAMD51P20, and Interface > SWD. Click Apply.
   • Click Read. The empty fields for ‘Device Signature’ and ‘Target Voltage’ will populate.
4. In the same ‘Device Programming’ window, select Fuses.
   • Change the value of USER_WORD_0.NVMCTRL_BOOTPROT to 0x0F or 0 kbytes (whichever shows up).
   • At the bottom of the window, click Program and then Verify to make sure the fuse has been set correctly.

That should be it. The J-Link GDB Server should now work as expected. Congrats on setting up your brand-new devboard!

---

Adding a New File to the Project

Note: This does not apply to .h files (although, you should still follow step 1)

1. Take 30 full seconds to think about the scope and name of this file:

   • Does the name encompass everything the file could end up doing?
   • Is there a distinct logical separation between the role of this file and any other files?
   • Does it follow existing naming conventions (within the folder, and within the project)?
   • Does it belong in the folder you are adding it to? Will the file always be doing things within this category?

2. Modify the Makefile to add the new file to the list of objects to be compiled:

   • Add the file’s name to the OBJS list, with the .o extension instead of .c
   • If the file is in a new folder, add the newly created folder to the EXTRA_VPATH list as well

3. If anything gives you trouble, run a quick make clean to clear out any old object files

---

How to Update the ASF Library:

1. Go to Atmel Start and use the atmel_start_config.atstart file in the root of this repository to import the project.
2. Make any desired changes.
3. Export the project with the Makefile box checked, and the name ASF.
   • This will result in a file named ASF.atzip. Do not change this name.
4. Place the ASF.atzip file in the root of this repository.
5. Run make update_asf to update the ASF library. This will completely wipe the ASF folder, so be careful!
   • Because of this, you should not put anything in the ASF folder that is not autogenerated by Atmel Start.
6. Ideally, there should be nothing to be done after make update_asf completes. Try to make clean and make to verify it all works.