Pico-Setup-Ada

Description how to set up an Ada development environment for Raspberry Pico or similar rp2040/rp2350 boards

create separate pages for Windows and Linux or do it in parallel?

flowchart LR
    id1[Alire]
    id2[Build Essentials]
    id3[OpenOCD]
    id4[Toolchain]
    id5[IDE]
    id1 --> id2 --> id3 --> id4 --> id5

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Set-Up Alire

Alire is the Ada package manager. It manages dependancies between libraries and tools. Download the latest version from their Github repository.

Windows

The installer creates a desktop icon that starts a Powershell. The PATH is automatically extended for the alr binary.

Linux

The downloaded archive essentially contains the only file bin/alr. You better extract it being in your home directory. The installation path ~/bin/ is already in your PATH most probably.

Install the Build Essentials

You need several other tools and libraries besides a compiler and an editor like make, git for version control, unzip, libusb, etc.

Windows

On the first invocation of alr it proposes to download Msys2 and associated tools for you. If you already have Msys2 you can configure Alire to use the preinstalled Msys2. In that case I recommend to add the Alire installation directory to you PATH, e.g. in your .profile.

Linux

Linux already has all the necessary tools. In case you are missing something install it with your Linux package manager.

$ apt install build-essential git

Install the Debugger OpenOCD

The standard way to install your binaries on the Pico board is to copy an uf2 file to it. I highly recommend, however, to use a debugger via the Serial Wire Debug (SWD) interface. You first need the software OpenOCD and a second Pico that works as a debug probe. The standard package managers for Windows and Linux provide at least version 0.12 that works with the rp2040 chips. Second, you need the GNU debugging program gdb.

The stock OpenOCD distributions V0.12 (Windows and Linux as well) has a nasty bug in that stops timers. See here. A solution is the upstrewam sources and in the fork of the Raspberry Foundation. Perhaps there is also a version of OpenOCD that gets installed through the VSCode extension that does not show the problem, to be confirmed.

Install Software on Windows

pacman -S mingw-w64-ucrt-x86_64-openocd
pacman -S mingw-w64-ucrt-x86_64-gdb

USB Driver

As explained in the official guide, you need to make sure that the right USB drivers are being used. Download Zadig from http://zadig.akeo.ie and run it. First select Options / List all devices from the menu. Then you can chose Picoprobe (Interface 2) and make sure it's using the libusb-win32 driver.

Install Software on Linux

apt install openocd gdb

You can find further information about OpenOCD on Debian at their wiki.

Second Pico as Debug Probe

See the setup guide on how to install software and how to wire the second Pico board.

Select Tool-Chain

Run the command

alr toolchain --select

and select the line gnat_arm_elf. If you are asked to select gprbuild pick the newest one.

Select an IDE (VSCode and Emacs with Ada-Mode)

Create the Initial Frame for Your Own Project

(this is taken almost verbatim from Jeremy Grosser's site).

Use Alire to create a skeleton project and add a dependency on pico_bsp.

alr init --bin hello_pico
cd hello_pico
alr with pico_bsp

Next, edit hello_pico.gpr to import pico_bsp and add the Target, Runtime, and Linker configuration near the top.

with "config/hello_pico_config.gpr";
with "pico_bsp.gpr";                                          --  < add
project Hello_Pico is
   for Target use "arm-eabi";                                 --  < add
   for Runtime ("Ada") use "light-cortex-m0p";                --  < add
   package Linker is                                          --  < add
      for Switches ("Ada") use Pico_BSP.Linker_Switches;      --  < add
   end Linker;                                                --  < add

   for Source_Dirs use ("src/", "config/");

Build the Sample Program

Build the project.

alr build --development

If the build was successful, there will be an ELF binary in ./bin/hello_pico.

Debug the Sample Program

upload program

You first have to upload the generated elf file to the target board. Connect the Pico_Probe via USB to your computer and the SWD wires from the Pico_Probe to the corresponding pins on your target Pico. You can then upload the program using OpenOCD.

openocd -f interface/cmsis-dap.cfg -f target/rp2040.cfg -s tcl -c "adapter speed 5000" -c "program bin/hello_pico verify reset exit"

Start OpenOCD for Debugging

openocd -f interface/cmsis-dap.cfg -f target/rp2040.cfg -s tcl -c "set USE_CORE 0" -c "adapter speed 5000"

set USE_CORE 0 should circumvent a problem when debugging timers adapter speed 5000 increases communication speed to the target

Another workaround is to set timer_hw->dbgpause (what is that in Ada?) to 0 in your startup code.

Look at Other Examples