dropped nightly requiremet, README

README.md

@@ -7,6 +7,10 @@
 
 Adds debug to volatile register when compiled with `--features debug-fmt`.
 
+## Caveats
+
+Notice, the current implementation of `array-debug` (see `examples/example2.rs`) requires a nightly toolchain (`#![feature(unsize)]`). This is however an "opt-in", and needed to support `#[derive(Debug)]` for cases with (register) arrays larger than 32 elements.
+
 
 ``` rust
 extern crate volatile_register;
@@ -39,7 +43,7 @@ Nvic { iser: [0xB618860, 0x7FFE, 0x20, 0x0, 0x0, 0x7F70, 0x30, 0x0], reserved0:
 
 Registers will be formatted under `UpperHex`, notice in the example that arrays are of size less than 32, hence `Debug` of array (`[T; N]`) is implemented by default. Notice that the `reserved` fields falls back to the default integer formatting (as not wrapped by the `volatile-register` abstraction).
 
-For register arrays with more then 32 items, `array-debug` provides a newtype over array, replicating the array behavior while providing `Debug`.
+For register arrays with more then 32 elements, `array-debug` provides a newtype over array, replicating the array behavior while providing `Debug`.
 
 ``` rust
 extern crate array_debug;