More work on docs

Author: jamesmunns

book/src/tutorial/104-sdk.md

@@ -256,3 +256,53 @@ $ cargo run --release
 Current state: '{"b":0,"g":0,"r":0}'
 Updated state: '{"b":255,"g":255,"r":255}'
 ```
+
+### With Shared types
+
+In order to share types, we'll need to have a crate that can be included by both the firmware device,
+as well as our host application.
+
+The ICD for the simulators supported by poststation are available [on GitHub](https://github.com/OneVariable/poststation-util/tree/main/crates/poststation-sim-icd),
+and published as `poststation-sim-icd`. We can go ahead and add that to our example project:
+
+```sh
+$ cargo add poststation-sim-icd
+    Updating crates.io index
+      Adding poststation-sim-icd v0.1.0 to dependencies
+...
+```
+
+This gives us access to the types we need.
+
+Now we can access the same endpoints as above, but without having to deal with JSON types:
+
+```rust
+// Import endpoint names and types from the ICD crate
+use poststation_sim_icd::simulator::{GetStatusLed, Rgb8, SetStatusLed};
+
+let response = client.proxy_endpoint::<GetStatusLed>(serial, 10, &()).await;
+let Ok(color) = response else {
+    println!("First Request failed!");
+    return;
+};
+println!("initial status: {color:?}");
+let new = Rgb8 { r: !color.r, g: !color.g, b: !color.b };
+
+// Now set a new color
+let response = client.proxy_endpoint::<SetStatusLed>(serial, 11, &new).await;
+let Ok(()) = response else {
+    println!("Second Request failed!");
+    return;
+};
+
+// And verify the result
+let response = client.proxy_endpoint::<GetStatusLed>(serial, 12, &()).await;
+let Ok(new_color) = response else {
+    println!("Third Request failed!");
+    return;
+};
+
+println!("New status: {new_color:?}");
+assert_eq!(new, new_color);
+println!("Success!");
+```

book/src/tutorial/200-rp2040.md

@@ -1 +1,3 @@
 # Using an RP2040
+
+Coming soon! Check out the `templates` and `examples` folder of <https://github.com/OneVariable/poststation-util>!

tools/poststation-sdk/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "poststation-sdk"
-# This version of the SDK tested with poststation v0.14.0
+# This version of the SDK tested with poststation v0.15.0
 version = "0.4.1"
 edition = "2021"
 authors = ["James Munns <[email protected]>"]