The links to the Raspberry Pi Pico Dev Board appear to be broken (Archive Link).

Its possible that this page has been migrated to a new domain:

• https://savageelectronics.com/category/raspberry-pi-pico/

Need to find out where it's gone and replace the links.

Currently, the project skeleton recommends the usage of DapperMime to transform a Raspberry Pi Pico into a CMSIS-DAP debug probe.

According to a comment thread in the embassy chat, a faster alternative rust-dap exists:

9names
dapper-mime works, but rust-dap is faster as it supports cmsis-dap v2 and uses the rp2040 PIO to drive SWD. here's a build of that to test on, if you're interested
https://raw.githubusercontent.com/9names/binary-bits/main/rust-dap-pico-ramexec-setclock.uf2

Peter Hansen
Always happy to upgrade things! :-) And that's awesome that someone put PIO to use for this.
Is that build based on https://github.com/ciniml/rust-dap ? (Just checking, 'cause that one says it's no faster than other probe implementations, and doesn't mention v2 at least on the readme.)

9names
it is a build of that, yes the readme is out of date
i did some performance profiling earlier this year. cmsis-dap v1 firmwares cap out at around 22KB/sec, cmsis-dap v2 + bit-banging at around 54KB/sec, and cmsis-dap v2 + PIO at about 116KB/sec - we're getting capped by USB FS throughput at that speed unfortunately.
if we had USB HS on rp2040 I assume we would be getting 3-4 times that, which would put us at HS-probe levels of performance

The rust-dap firmware should be investigated, and if it proves to be better than DapperMime then it should replace it in this repository.

The embassy rp example provides a memory.x file. However, this project does not compile without the additional bootloader section in memory.x

https://github.com/embassy-rs/embassy/blob/master/examples/rp/memory.x

MEMORY {
    BOOT2 : ORIGIN = 0x10000000, LENGTH = 0x100
    FLASH : ORIGIN = 0x10000100, LENGTH = 2048K - 0x100
    RAM   : ORIGIN = 0x20000000, LENGTH = 256K
}

https://github.com/SupImDos/embassy-rp-skeleton/blob/main/memory.x

MEMORY {
    BOOT2 : ORIGIN = 0x10000000, LENGTH = 0x100
    FLASH : ORIGIN = 0x10000100, LENGTH = 2048K - 0x100
    RAM   : ORIGIN = 0x20000000, LENGTH = 256K
}

EXTERN(BOOT2_FIRMWARE)

SECTIONS {
    /* ### Boot loader */
    .boot2 ORIGIN(BOOT2) :
    {
        KEEP(*(.boot2));
    } > BOOT2
} INSERT BEFORE .text;

The embassy rp example also provides a build.rs that includes the following line, which is missing in our equivalent .cargo/config.toml

https://github.com/embassy-rs/embassy/blob/master/examples/rp/build.rs#L34

cargo:rustc-link-arg-bins=-Tlink-rp.x

This line points us towards the link-rp.x.in file in embassy-rp, which actually includes the bootloader section of our memory.x file.

https://github.com/embassy-rs/embassy/blob/master/embassy-rp/link-rp.x.in

SECTIONS {
    /* ### Boot loader */
    .boot2 ORIGIN(BOOT2) :
    {
        KEEP(*(.boot2));
    } > BOOT2
}

It appears likely then, if we add the following line to the rustflags of our .cargo/config.toml then we can update our memory.x to the more terse version

"-C", "link-arg=-Tlink-rp.x",

Thank you for creating such a great skeleton!

I would like to use this skeleton for my project, but I could not find a license for this skeleton, so I cannot use it.

So, could you please add the license file?