diff --git a/src/lib.rs b/src/lib.rs
index 7161408..0a8c370 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -14,18 +14,21 @@ mod test;
 
 /// Backend interface for `Store`
 pub trait StoreBackend {
+    /// type returned by `data()` for reading the flash
     type Data: ?Sized + AsRef<[u8]>;
 
-    /// Memory-mapped
+    /// memory-mapped
     fn data(&self) -> &Self::Data;
+    /// size of flash page
     fn len(&self) -> usize {
         self.data().as_ref().len()
     }
 
+    /// error type returned by `erase()`/`flash()` operations
     type Error;
-    /// erase flash
+    /// erase flash page
     fn erase(&mut self) -> Result<(), Self::Error>;
-    /// program flash
+    /// program flash with offset into flash page
     fn program(&mut self, offset: usize, payload: &[u8]) -> Result<(), Self::Error>;
     /// called after repeated `program()` invocations to allow for eg. cache flushing
     fn program_done(&mut self) {}
diff --git a/src/no_flash.rs b/src/no_flash.rs
index ba7ca33..b0875ce 100644
--- a/src/no_flash.rs
+++ b/src/no_flash.rs
@@ -1,3 +1,5 @@
+//! Support for configurations without flash
+
 use crate::StoreBackend;
 use core::fmt;