edited back matter

Author: BartMassey

mdbook/src/appendix/1-general-troubleshooting/README.md

@@ -1,13 +1,12 @@
 # General troubleshooting
 
 ## `cargo-embed` problems
-Most `cargo-embed` problems are either related to not having installed the `udev`
-rules properly (on Linux) or having selected the wrong chip configuration in `Embed.toml` so
-make sure you got both of those right.
 
-If the above does not work out for you, you can open an issue in the [`discovery` issue tracker].
-Alternatively you can also visit the [Rust Embedded matrix channel] or the [probe-rs matrix channel]
-and ask for help there.
+Most `cargo-embed` problems are related to not having installed the `udev` rules properly on
+Linux, so make sure you got that right.
+
+If you are stuck, you can open an issue in the [`discovery` issue tracker] or visit the [Rust
+Embedded matrix channel] or the [probe-rs matrix channel] and ask for help there.
 
 [`discovery` issue tracker]: https://github.com/rust-embedded/discovery/issues
 [Rust Embedded matrix channel]: https://matrix.to/#/#rust-embedded:matrix.org
@@ -17,7 +16,7 @@ and ask for help there.
 
 ### "can't find crate for `core`"
 
-#### Symptoms
+*Symptoms:*
 
 ```
    Compiling volatile-register v0.1.2
@@ -42,11 +41,11 @@ error: Could not compile `r0`.
 To learn more, run the command again with --verbose.
 ```
 
-#### Cause
+*Cause:*
 
 You forgot to install the proper target for your microcontroller `thumbv7em-none-eabihf`.
 
-#### Fix
+*Fix:*
 
 Install the proper target.
 

mdbook/src/appendix/2-how-to-use-gdb/README.md

@@ -1,10 +1,15 @@
 # How to use GDB
 
-Below are some useful GDB commands that can help us debug our programs. This assumes you have [flashed a program](../../05-led-roulette/flash-it.md) onto your microcontroller and attached GDB to a `cargo-embed` session.
+Below are some useful GDB commands that can help us debug our programs. This assumes you have
+[flashed a program](../../05-led-roulette/flash-it.md) onto your microcontroller and attached GDB to
+a `cargo-embed` session.
 
 ## General Debugging
 
-> **NOTE:** Many of the commands you see below can be executed using a short form. For example, `continue` can simply be used as `c`, or `break $location` can be used as `b $location`. Once you have experience with the commands below, try to see how short you can get the commands to go before GDB doesn't recognize them!
+> **NOTE:** Many of the commands you see below can be executed using a short form. For example,
+> `continue` can simply be used as `c`, or `break $location` can be used as `b $location`. Once you
+> have experience with the commands below, try to see how short you can get the commands to go
+> before GDB doesn't recognize them!
 
 
 ### Dealing with Breakpoints
@@ -40,7 +45,8 @@ Below are some useful GDB commands that can help us debug our programs. This ass
 
 ### Printing Information
 
-* `print /$f $data` - Print the value contained by the variable `$data`. Optionally format the output with `$f`, which can include:
+* `print /$f $data` - Print the value contained by the variable `$data`. Optionally format the
+  output with `$f`, which can include:
     ```txt
     x: hexadecimal
     d: signed decimal
@@ -52,21 +58,25 @@ Below are some useful GDB commands that can help us debug our programs. This ass
     f: floating point
     ```
     * `print /t 0xA`: Prints the hexadecimal value `0xA` as binary (0b1010)
-* `x /$n$u$f $address`: Examine memory at `$address`. Optionally, `$n` define the number of units to display,
-  `$u` unit size (bytes, halfwords, words, etc.), `$f` any `print` format defined above
+
+* `x /$n$u$f $address`: Examine memory at `$address`. Optionally, `$n` define the number of units to
+  display, `$u` unit size (bytes, halfwords, words, etc.), `$f` any `print` format defined above
     * `x /5i 0x080012c4`: Print 5 machine instructions staring at address `0x080012c4`
     * `x/4xb $pc`: Print 4 bytes of memory starting where `$pc` currently is pointing
 * `disassemble $location`
-    * `disassemble /r main`: Disassemble the function `main`, using `/r` to show the bytes that make up each instruction
+    * `disassemble /r main`: Disassemble the function `main`, using `/r` to show the bytes that make
+      up each instruction
 
 
 ### Looking at the Symbol Table
 
-* `info functions $regex`: Print the names and data types of functions matched by `$regex`, omit `$regex` to print all functions
+* `info functions $regex`: Print the names and data types of functions matched by `$regex`, omit
+  `$regex` to print all functions
     * `info functions main`: Print names and types of defined functions that contain the word `main`
 * `info address $symbol`: Print where `$symbol` is stored in memory
     * `info address GPIOC`: Print the memory address of the variable `GPIOC`
-* `info variables $regex`: Print names and types of global variables matched by `$regex`, omit `$regex` to print all global variables
+* `info variables $regex`: Print names and types of global variables matched by `$regex`, omit
+  `$regex` to print all global variables
 * `ptype $data`: Print more detailed information about `$data`
     * `ptype cp`: Print detailed type information about the variable `cp`
 
@@ -79,7 +89,8 @@ Below are some useful GDB commands that can help us debug our programs. This ass
 * `down $n`: Select frame `$n` frames down
 * `info frame $address`: Describe frame at `$address`, omit `$address` for currently selected frame
 * `info args`: Print arguments of selected frame
-* `info registers $r`: Print the value of register `$r` in selected frame, omit `$r` for all registers
+* `info registers $r`: Print the value of register `$r` in selected frame, omit `$r` for all
+  registers
     * `info registers $sp`: Print the value of the stack pointer register `$sp` in the current frame
 
 ### Controlling `cargo-embed` Remotely

mdbook/src/appendix/3-mag-calibration/README.md

@@ -15,7 +15,7 @@ describes the procedure if you are interested in the details.
 
 [Design Note]: https://www.st.com/resource/en/design_tip/dt0103-compensating-for-magnetometer-installation-error-and-hardiron-effects-using-accelerometerassisted-2d-calibration-stmicroelectronics.pdf
 
-Luckily for us, the CODAL group that built the original software for the micro:bit already
+Luckily for us, the CODAL group that built the original C++ software for the micro:bit already
 implemented the manufacturer calibration mechanism (or something similar) in C++ over [here].
 
 [here]: https://github.com/lancaster-university/codal-microbit-v2/blob/006abf5566774fbcf674c0c7df27e8a9d20013de/source/MicroBitCompassCalibrator.cpp
@@ -26,7 +26,7 @@ when reading calibrated values *the axes are flipped* so that viewed from the to
 connector forward the X, Y and Z axes of the calibrated value are in "standard" (right, forward, up)
 orientation.
 
-The usage of this calibrator is demonstrated in the default `src/main.rs` file.
+The usage of this calibrator is demonstrated in `src/main.rs` here.
 
 The way the user does the calibration is shown in this video from the C++ version. (Ignore the
 initial printing — the calibration starts about halfway through.)