embedded-trainings-2020/embedded-workshop-book/src/generating-pac.md

Generating the PAC

Generate your own PAC from an SVD file.

In this exercise you will learn how to

• generate a PAC from an SVD file.
• format the generated code.
• split the single PAC file into one file per module.

Prerequisites

• usage of cargo install
• generating docs

Tasks

• Install svd2rust and form via cargo.
• Download the [nrf-svd][svd] file and place it into down-the-stack/dk-pac.
• Run svd2rust on the file using the cortex-m target.
• Format the generated file to make it readable.
• Split the file into its modules using form.
• Check the documentation.

Step-by-Step Solution

✅ Install the necessary tools using the following commands:

cargo install svd2rust
cargo install form

✅ Download [nrf-svd][svd](This version has an error: writeonce needs to be changed to writeOnce) Place the file into down-the-stack/dk-pac. Note how we provide a Cargo.toml file, as it will not be generated by svd2rust.

✅ In the terminal, go to the file's location. Run svd2rust with the SVD file to generate a PAC using the cortex-m flag.

svd2rust --target cortex-m -i nrf52.svd

If you check the folder down-the-stack/dk-pac now, you see three new files:

• lib.rs - the file that contains the generated code for the pac
• device.x - linker sections(?)
• build.rs - linker script

✅ Make an /src and move the generated lib.rs into it.

✅ Open the generated lib.rs with an editor. Notice how it's barely correctly formatted.

✅ Look at the PAC docs with the following command:

cargo doc --open

✅ Format the crate using cargo fmt. This does not change to the docs, but lib.rs is a bit more readable.

✅ Use form to process the lib.rs to split it into modules, so that each module in in it's own file.

form -i src/lib.rs -o src/ 

✅ Re-run cargo fmt.

[svd]: (https://github.com/NordicSemiconductor/nrfx/blob/master/mdk/nrf52.svd )