can: Clarify matching logic for filters

The logic for the RTR bit was inverted

Author: timokroeger

src/can.rs

@@ -136,26 +136,28 @@ pub trait Filter {
 
     /// Applies a mask to the filter.
     ///
+    /// A filter matches when: `<ReceiveID> & Mask == FilterID & Mask`
+    ///
     /// # Example
     ///
-    ///    Filter ID:  0b100110111
-    ///    Mask:       0b000001111
+    ///    FilterID:  0b100110111
+    ///    Mask:      0b000001111
     ///    
-    ///    Receive ID: 0b100110011
-    ///                        \----> Not accepted (bit 3 did not match)
+    ///    ReceiveID: 0b100110011
+    ///                       \----> Not accepted (3rd bit did not match)
     ///    
-    ///    Receive ID: 0b000000111 -> accepted
+    ///    ReceiveID: 0b000000111 -> accepted
     fn with_mask(&mut self, mask: u32) -> &mut Self;
 
     /// Makes the filter acccept both data and remote frames.
     ///
-    /// Sets the RTR bit in the filter mask.
+    /// Clears the RTR bit in the filter mask.
     /// Only available for filters with `RtrFilterBehavior::Configurable`.
     fn allow_remote(&mut self) -> &mut Self;
 
     /// Makes the filter acccept remote frames only.
     ///
-    /// Sets the RTR bit in the filter and clears it in the mask (if available).
+    /// Sets the RTR bit in both the filter and the mask (if available).
     /// Only available for filters with `RtrFilterBehavior::Configurable` or
     /// `RtrFilterBehavior::ConfigurableEitherDataOrRemote`.
     fn remote_only(&mut self) -> &mut Self;