diff --git a/ports/arm/atomport.h b/ports/arm/atomport.h
index 6198a19..1025b18 100644
--- a/ports/arm/atomport.h
+++ b/ports/arm/atomport.h
@@ -61,7 +61,7 @@ extern int32_t archUsecDiff (int32_t start_time);
 /**
  * ISR handler registration (optional, not available on all ports)
  */
-typedef void (*ISR_FUNC)(void);
+typedef void (*ISR_FUNC)(int int_vector);
 extern int archIntInstallISR (int int_vector, ISR_FUNC isr_func);
 extern int archIntEnable (int int_vector, int enable);
 
diff --git a/ports/arm/platforms/dm36x/atomport-private.c b/ports/arm/platforms/dm36x/atomport-private.c
index c045f31..e36d068 100644
--- a/ports/arm/platforms/dm36x/atomport-private.c
+++ b/ports/arm/platforms/dm36x/atomport-private.c
@@ -54,7 +54,7 @@ static ISR_FUNC isr_handlers[DM36X_INTC_MAX_VEC + 1] =
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
-  atomTimerTick, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
+  (void *)atomTimerTick, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 
   NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL };
@@ -276,7 +276,7 @@ __interrupt_dispatcher (void)
             atomIntEnter();
 
             /* Call the registered ISR */
-            isr_handlers[vector]();
+            isr_handlers[vector](vector);
 
             /* Call the interrupt exit routine */
             atomIntExit(TRUE);