diff --git a/README.md b/README.md
index 089af76..3045af6 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,20 @@ GNAT's System'To_Address attribute is used in peripherials definitions
 (STM32.*model-name*.Units packages).
 I currently cannot decide if Preelaborate is really needed there.
 
+## Common implementation notes
+
+### Interrupts
+
+Interrupt handling in multitasked (Ravenscar) profiles require support from OS / RTL.
+That is, no interrupt definitions done there.
+Use `Ada.Interrupts.Names` to define interrupt handlers.
+This obviously limit the set of supported devices to ones supplied with compiler.
+
+Interrupts in minimal (ZFP) profiles though do not require any system support
+as they fully handled by user code.
+However interrupt vector table should be implementer by the user too.
+For this maybe some constants will be set.
+
 ## Hardware quirks and workarounds
 
 ### APB