the Nested Vectored Interrupt Controller
procedure Clear_Pending (IRQn : Interrupt_ID)
procedure Disable_Interrupt (IRQn : Interrupt_ID)
procedure Enable_Interrupt (IRQn : Interrupt_ID)
function Enabled (IRQn : Interrupt_ID) return Boolean
type Interrupt_ID is new Natural range 0 .. 31;
type Interrupt_Priority is new UInt8 range 0 .. (2**NVIC_PRIO_BITS - 1);
NVIC_PRIO_BITS : constant := 2;
All Cortex M0 parts have 2 bit priority mask
function Pending (IRQn : Interrupt_ID) return Boolean
procedure Set_Pending (IRQn : Interrupt_ID)
procedure Set_Priority
(IRQn : Interrupt_ID;
Priority : Interrupt_Priority)