docs: move captains log, use obsidian for notes

.gitignore

@@ -24,3 +24,6 @@ Cargo.lock
 .env
 .DS_Store
 desktop.ini
+
+# Obsidian
+.obsidian/

docs/.gitignore

@@ -1 +1,2 @@
 book
+.obsidian

docs/SUMMARY.md

@@ -14,8 +14,3 @@
 - [debugging](hello-world/debugging.md)
 - [blinky](hello-world/blinky.md)
 
----
-
-# Development
-
-- [captain's log](captains-log.md)

docs/captains-log/2024-12-17.md

@@ -0,0 +1,109 @@
+## 2024-12-17
+
+Ahab is a fitting name for this project. It is a high altitude balloon. It is
+cheeky. It is a bit of a jerk. It is a bit of a showoff. It is a bit of a thing
+I keep chasing and chasing and chasing. It's also a nod to the "alumni hab"
+brickworks project that became [Nucleus](https://github.com/Brickworks/Nucleus).
+
+I'm going to try to keep a log of my thoughts and ideas here, like a captain
+losing his mind at sea.
+
+Some things I have floating around in my head:
+
+1. I really like mdBook. I think it's a great way to write documentation.
+2. I found the following things in my drawer.
+   - tiny gps breakout https://www.sparkfun.com/products/retired/10995
+   - rpi 4b
+   - rpi zero w 1.1
+   - msp430
+   - stm32F411e
+   - arduino mkr fpga https://www.arduino.cc/en/Guide/MKRVidor4000
+   - a TTL camera
+3. I would really like to build out [yahs](https://github.com/philiplinden/yahs)
+   into a thing that can be used to build and test a high altitude balloon,
+   more than just a thing I use to learn rust.
+4. I want to explore embedded rust.
+5. I want to finish what [Nucleus](https://github.com/Brickworks/Nucleus)
+   started. We had a lot of good ideas and made a lot of mistakes. I want to
+   finish what we started.
+
+I set up this repository and started writing some documentation, including some
+notes on what I want out of this project.
+
+I flashed the Raspberry Pi 4B with Raspberry Pi OS Lite and was able to
+successfully SSH into it on my local network. Even if I end up using the Pi
+Zero for flight, the 4B is really easy to set up on the network, has plenty of
+headroom, and will serve as a good testbed for now. It could also host other
+development services like a web server, database, Jenkins, etc if I need it to.
+
+https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials
+
+I should start using Linear for project management for this. I probably won't
+stick to it very well, but it will be good practice.
+
+I found some great rust CI examples in the
+[actions-rs](https://github.com/actions-rs) repo. I'm going to use them to set
+up a build workflow for this project.
+
+I set up a template for the STM32F411E board.
+https://studiofuga.com/blog/2022-10-18-getting-started-with-rust-and-stm32f411/
+
+I set up a template for the MSP432 too.
+- https://github.com/rust-embedded/msp430-quickstart (not this board, but close)
+- https://docs.rs-online.com/3934/A700000006811369.pdf
+- https://github.com/MSP432P401R-Launchpad-Rust
+- https://github.com/msp432-rust/msp432p401r-hal
+- https://github.com/msp432-rust/msp432p401r-pac
+- https://github.com/pcein/msp432p401r
+- https://github.com/pcein/msp432-newio
+
+Turns out the MSP432 uses the TM4C129 chip, which can be used with the
+[cortex-m-quickstart](https://docs.rs/cortex-m-quickstart/~0.2.3) cargo-generate
+template. I set that up but I'm not sure if the `memory.x` file is correct.
+
+I ended up fighting the compiler for a while, trying to get the panic handler
+to work. I ended up just using the `panic-semihosting` crate for now because
+that's what would compile. Using `panic-halt` or `panic-abort` required using
+deprecated features I guess? After switching to the `panic-semihosting` crate, I
+started running into linker errors. I'll have to figure this out later once I
+am actually flashing the boards with code I understand, rather than templates.
+
+The root cause looks to be related to this comment
+[from the miri repo](https://github.com/rust-lang/miri/issues/3498):
+> you added a crate as dependency that depends on std, and built a sysroot
+> without std, and then that fails to build. No surprise here.
+
+Oh well.
+
+I thought some more about how to structure the project so that I can swap out
+blocks of logic easily between simulated code on my PC, code running on a board
+in a hardware-in-the-loop simulation, and actual code running on the board in
+the real world. With Rust, hopefully we can write tests and benchmarks for the
+software and firmware so that they behave exactly the same way in each case. The
+tricky bit is how to handle the interface between the simulated environments and
+the real environments for things like sensors and actuators.
+
+--> [design/structure.md](design/structure.md)
+
+And now, it's time to [dive in to embedded rust](https://youtu.be/TOAynddiu5M).
+
+I deleted most of the template code and started from scratch following this
+tutorial and documenting the process in
+[docs/hello-worldgetting-started.md](docs/hello-worldgetting-started.md). I can always
+re-use the template code if I need it, but building up from scratch is great
+practice to learn what all of these files do and how they fit together.
+
+Woohoo! I got a (dummy) program to compile for the STM32F411E board! Now to
+flash it... Nice, it worked!
+
+There is one hang up though. When I `cargo build` from the root, it tries to
+compile the embedded crates for the host arch. I want to edit `Cargo.toml` at
+the root to effectively do the same thing as specifying the target arch in
+`.cargo/config.toml` for each crate.
+
+https://doc.rust-lang.org/cargo/reference/unstable.html#per-package-target
+
+https://nnarain.github.io/2021/08/02/Setting-up-per-package-targets-in-Rust.html
+
+I had to add `cargo-features = ["per-package-target"]` to the `Cargo.toml` file,
+which is an unstable `nightly` feature.