edited ch 2

mdbook/src/02-requirements/README.md

@@ -1,38 +1,45 @@
 # Hardware/knowledge requirements
 
-The primary knowledge requirement to read this book is to know *some* Rust. It's
-hard for me to quantify *some* but at least I can tell you that you don't need
-to fully grok generics, but you do need to know how to *use* closures. You also
-need to be familiar with the idioms of the current Rust [edition].
+The primary knowledge requirement to read this book is to know *some* Rust. It's hard for me to
+quantify *some*. Being familiar with the basics of generics and traits is quite helpful. You do need
+to know how to *use* closures. You also need to be familiar with the idioms of the current Rust
+[edition].
 
 [edition]: https://rust-lang-nursery.github.io/edition-guide/
 
-Also, to follow this material you'll need the following hardware:
+Also, to follow this material you'll need:
 
 - A [Micro:Bit v2] (MB2) board.
 
-[micro:bit v2]: https://tech.microbit.org/hardware/
+  [micro:bit v2]: https://tech.microbit.org/hardware/
 
-You can purchase this board from many suppliers, including
-Amazon and Ali Baba. You can get a [list][0] of suppliers
-directly from the BBC, the manufacturers of MB2.
+  You can purchase this board from many suppliers, including
+  Amazon and Ali Baba. You can get a [list][0] of suppliers
+  directly from the BBC, the manufacturers of MB2.
 
-[0]: https://microbit.org/buy/
+  [0]: https://microbit.org/buy/
 
-<p align="center">
-<img title="micro:bit" src="../assets/microbit-v2.jpg">
-</p>
+  <p align="center">
+  <img title="micro:bit" src="../assets/microbit-v2.jpg" width="500"/>
+  </p>
 
-- One micro-B USB cable (nothing special — you probably have many of these). This is required
+  There are several versions of the `V2` board
+  available. While the material here was written for `V2.00`,
+  things should work fine with with any `V2` board.
+
+- A micro-B USB cable (nothing special — you probably have many of these). This is required
   to power the micro:bit board when not on battery, and to communicate with it.  Make sure
   that the cable supports data transfer, as some cables only support charging devices.
 
-<p align="center">
-<img title="micro-B USB cable" src="../assets/usb-cable.jpg">
-</p>
+  <p align="center">
+  <img title="micro-B USB cable" src="../assets/usb-cable.jpg" width="500">
+  </p>
+
+  > **NOTE** Some micro:bit kits ship with such cables.  USB cables used with other mobile
+  > devices should work, if they are micro-B and have the capability to transmit data.
 
-> **NOTE** Some micro:bit kits ship with such cables.  USB cables used with other mobile
-> devices should work, if they are micro-B and have the capability to transmit data.
+  The official `micro:bit Go` kit provides both the USB cable and a nifty battery pack for powering
+  the MB2 without USB.
 
 > **FAQ**: Wait, why do I need this specific hardware?
 
@@ -44,17 +51,18 @@ Trust me on this one.
 > **FAQ**: Can I follow this material with a different development board?
 
 Maybe? It depends mainly on two things: your previous experience with microcontrollers and/or
-whether a high level crate already exists, like the [`nrf52-hal`], for your development board
-somewhere. You can look through the [Awesome Embedded Rust HAL list] for your microcontroller,
-if you intend to use a different one.
+whether a high level crate already exists for your development board somewhere. You probably want at
+least a HAL crate, like [`nrf52-hal`] used here.  You may prefer a board with a Board Support crate,
+like [`microbit-v2`] used here.  If you intend to use a different microcontroller, you can look
+through [Awesome Embedded Rust] or just search the web to find supported crates.
 
 [`nrf52-hal`]: https://docs.rs/nrf52-hal
-[Awesome Embedded Rust HAL list]: https://github.com/rust-embedded/awesome-embedded-rust#hal-implementation-crates
+[Awesome Embedded Rust]: https://github.com/rust-embedded/awesome-embedded-rust
 
-With a different development board, this text would lose most if not all its beginner friendliness
-and "easy to follow"-ness, in my opinion.
+With a different development board, this text loses most if not all its beginner friendliness and
+"easy to follow"-ness, in my opinion: you have been warned.
 
-If you have a different development board and you don't consider yourself a total beginner, you are
-better off starting with the [quickstart] project template.
+If you have a different ARM-based development board and you don't consider yourself a total
+beginner, you might consider starting with the [quickstart] project template.
 
 [quickstart]: https://rust-embedded.github.io/cortex-m-quickstart/cortex_m_quickstart/