Update dependencies in Cargo.toml + build instructions

[tarcieri]

I was able to build and run the blink example on a SAML11 Xplained board with these changes 🎉

(the LED is blinking my attempt at "R-U-S-T" in morse code with some local changes I didn't check in)

Looks like you were able to upstream the thumbv8m.base-none-eabi target definition:

rust-lang/rust#55041

I was able to use that via rustup on a recent nightly, so no more need for (patched) xargo.

I went ahead and bumped all of the crates to the latest releases as I wasn't able to get anything to compile without doing so.

[tarcieri]

Also a quick note that I've been doing work on https://github.com/atsamd-rs/atsamd lately (targeting SAMD51) and some of it seems like it might be applicable on these.

I might also be interested in contributing/collaborating on an embedded-hal impl for these.

[evq]

Awesome, glad to hear it works with nightly and released versions of all the deps!

I have the very early beginnings of a embedded-hal implementation crate - just parts of gpio and spi. I used the hal implementation from atsamd as a starting point. It's pretty rough - mostly the same code as atsamd with bits commented out and a few L11 specific tweaks.

It also has a rand_core impl that uses the hardware rng and code to use the rom built-in sha256.

I'll push it up :)

[evq]

@tarcieri Pushed to https://github.com/evq/atsaml11xxx-hal

It's in pretty rough shape - but I upgraded the deps / got the blink example compiling and the host sha256 tests working.

My SAML11 Xplained is being uncooperative so I haven't been able to see if the hal blink is still working.

[tarcieri]

@evq nice, thank you!

[tarcieri]

@evq since you added rand_core support, I'm curious if you have thoughts on this issue: rust-embedded/wg#353