add initial driver implementation

this contains some basic test coverage using `embedded-hal-mock` but
requires dbrgn/embedded-hal-mock#52 to support the `PwmPin` trait. for
the time being the PR branch is being used as a git dependency, this
should be changed back to a normal dependency once the PR has been
merged and a new release of `embedded-hal-mock` has been published.

Cargo.toml

@@ -3,6 +3,14 @@ name = "tb6612fng"
 version = "0.1.0"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+description = "A `no_std` driver for the TB6612FNG motor driver."
+repository = "https://github.com/rursprung/tb6612fng-rs"
+keywords = ["tb6612fng", "embedded", "driver", "no_std", "motor", "dc motor", "controller"]
 
 [dependencies]
+embedded-hal = "0.2"
+
+defmt = { version = "0.3", optional = true }
+
+[dev-dependencies]
+embedded-hal-mock = { git = "https://github.com/rursprung/embedded-hal-mock.git", branch = "add-pwmpin-mock" }

README.md

@@ -0,0 +1,19 @@
+# Rust Driver for TB6612FNG Motor Driver
+This is a `no_std` driver for the [TB6612FNG motor driver](https://www.sparkfun.com/datasheets/Robotics/TB6612FNG.pdf) as can e.g. be found on the corresponding [SparkFun module](https://www.sparkfun.com/products/14450).
+
+Note that this work is not affiliated with any of the vendors of the controller or controller boards.
+
+The motor driver itself supports two motors and has a standby pin which controls both at the same time.
+The crate can be either used to control a single motor (using the `Motor` struct directly) or
+to control both motors (using the `Tb6612fng` struct) - the latter also supports using the standby functionality.
+
+See the documentation for usage examples.
+
+## When to use what
+* You plan on using both motors and the standby feature: use `Tb6612fng`
+* You plan on using both motors without the standby feature: use two separate `Motor`s
+* You plan on using a single motor with the standby feature: use `Motor` and control the standby pin manually
+* You plan on using a single motor without the standby feature: use `Motor`
+
+## Optional features
+* `defmt`: you can enable the [`defmt`](https://defmt.ferrous-systems.com/) feature to get a `defmt::debug!` call for every speed change.