Update to be compatible with RTFM

Author: James Munns

nrf52-hal-common/src/rtc.rs

@@ -82,7 +82,7 @@ where
     }
 
     /// Enable the generation of a hardware interrupt from a given stimulus
-    pub fn enable_interrupt(&mut self, int: RtcInterrupt, nvic: &mut NVIC) {
+    pub fn enable_interrupt(&mut self, int: RtcInterrupt, nvic: Option<&mut NVIC>) {
         match int {
             RtcInterrupt::Tick => self.periph.intenset.write(|w| w.tick().set()),
             RtcInterrupt::Overflow => self.periph.intenset.write(|w| w.ovrflw().set()),
@@ -91,11 +91,13 @@ where
             RtcInterrupt::Compare2 => self.periph.intenset.write(|w| w.compare2().set()),
             RtcInterrupt::Compare3 => self.periph.intenset.write(|w| w.compare3().set()),
         }
-        nvic.enable(T::INTERRUPT);
+        if let Some(nvic) = nvic {
+            nvic.enable(T::INTERRUPT);
+        }
     }
 
     /// Disable the generation of a hardware interrupt from a given stimulus
-    pub fn disable_interrupt(&mut self, int: RtcInterrupt, nvic: &mut NVIC) {
+    pub fn disable_interrupt(&mut self, int: RtcInterrupt, nvic: Option<&mut NVIC>) {
         match int {
             RtcInterrupt::Tick => self.periph.intenclr.write(|w| w.tick().clear()),
             RtcInterrupt::Overflow => self.periph.intenclr.write(|w| w.ovrflw().clear()),
@@ -104,7 +106,9 @@ where
             RtcInterrupt::Compare2 => self.periph.intenclr.write(|w| w.compare2().clear()),
             RtcInterrupt::Compare3 => self.periph.intenclr.write(|w| w.compare3().clear()),
         }
-        nvic.disable(T::INTERRUPT);
+        if let Some(nvic) = nvic {
+            nvic.disable(T::INTERRUPT);
+        }
     }
 
     /// Enable the generation of a hardware event from a given stimulus

nrf52-hal-common/src/timer.rs

@@ -60,26 +60,30 @@ where
     ///
     /// Enables an interrupt that is fired when the timer reaches the value that
     /// is given as an argument to `start`.
-    pub fn enable_interrupt(&mut self, nvic: &mut NVIC) {
+    pub fn enable_interrupt(&mut self, nvic: Option<&mut NVIC>) {
         // As of this writing, the timer code only uses
         // `cc[0]`/`events_compare[0]`. If the code is extended to use other
         // compare registers, the following needs to be adapted.
         self.0.intenset.modify(|_, w| w.compare0().set());
 
-        nvic.enable(T::INTERRUPT);
+        if let Some(nvic) = nvic {
+            nvic.enable(T::INTERRUPT);
+        }
     }
 
     /// Disables the interrupt for this timer
     ///
     /// Disables an interrupt that is fired when the timer reaches the value
     /// that is given as an argument to `start`.
-    pub fn disable_interrupt(&mut self, nvic: &mut NVIC) {
+    pub fn disable_interrupt(&mut self, nvic: Option<&mut NVIC>) {
         // As of this writing, the timer code only uses
         // `cc[0]`/`events_compare[0]`. If the code is extended to use other
         // compare registers, the following needs to be adapted.
         self.0.intenclr.modify(|_, w| w.compare0().clear());
 
-        nvic.disable(T::INTERRUPT);
+        if let Some(nvic) = nvic {
+            nvic.disable(T::INTERRUPT);
+        }
     }
 
     pub fn delay(&mut self, cycles: u32) {