started to clean up registers code

Author: BartMassey

Cargo.toml

@@ -3,8 +3,8 @@ resolver = "2"
 members = [
   "mdbook/src/03-setup",
   "mdbook/src/05-hello-world",
+  "mdbook/src/07-registers",
   "mdbook/src/05-led-roulette",
-# "mdbook/src/07-registers",
   "mdbook/src/09-uart",
   "mdbook/src/10-i2c",
   "mdbook/src/11-led-compass",

mdbook/src/07-registers/auxiliary/Cargo.toml

@@ -17,6 +17,12 @@
     - [Timers](05-hello-world/timers.md)
     - [Portability](05-hello-world/portability.md)
     - [Board support crate](05-hello-world/board-support-crate.md)
+- [Registers](07-registers/README.md)
+    - [RTRM](07-registers/rtrm.md)
+    - [(mis)Optimization](07-registers/optimization.md)
+    - [`0xBAAAAAAD` address](07-registers/bad-address.md)
+    - [Spooky action at a distance](07-registers/spooky-action-at-a-distance.md)
+    - [Type safe manipulation](07-registers/type-safe-manipulation.md)
 - [LED roulette](05-led-roulette/README.md)
     - [Build it](05-led-roulette/build-it.md)
     - [Flash it](05-led-roulette/flash-it.md)