| CMSIS-Core (Cortex-M) CMSIS-Core support for Cortex-M processor-based devices |

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Macros | Enumerations | Functions
Interrupts and Exceptions (NVIC)

Functions to access the Nested Vector Interrupt Controller (NVIC). More...

## Macros
#define | CMSIS_NVIC_VIRTUAL
| Virtualization of the NVIC API.
#define | CMSIS_VECTAB_VIRTUAL
| Virtualization of interrupt vector table access functions.

## Enumerations
enum | IRQn_Type { NonMaskableInt_IRQn = -14 , HardFault_IRQn = -13 , MemoryManagement_IRQn = -12 , BusFault_IRQn = -11 , UsageFault_IRQn = -10 , SecureFault_IRQn = -9 , SVCall_IRQn = -5 , DebugMonitor_IRQn = -4 , PendSV_IRQn = -2 , SysTick_IRQn = -1 , WWDG_STM_IRQn = 0 , PVD_STM_IRQn = 1 }
| Definition of IRQn numbers. More...

## Functions
void | NVIC_ClearPendingIRQ (IRQn_Type IRQn)
| Clear a device specific interrupt from pending.
uint32_t | NVIC_ClearTargetState (IRQn_Type IRQn)
| Clear Interrupt Target State.
void | NVIC_DecodePriority (uint32_t Priority, uint32_t PriorityGroup, uint32_t *pPreemptPriority, uint32_t *pSubPriority)
| Decode the interrupt priority [not for Cortex-M0, Cortex-M0+, or SC000].
void | NVIC_DisableIRQ (IRQn_Type IRQn)
| Disable a device specific interrupt.
void | NVIC_EnableIRQ (IRQn_Type IRQn)
| Enable a device specific interrupt.
uint32_t | NVIC_EncodePriority (uint32_t PriorityGroup, uint32_t PreemptPriority, uint32_t SubPriority)
| Encodes Priority [not for Cortex-M0, Cortex-M0+, or SC000].
uint32_t | NVIC_GetActive (IRQn_Type IRQn)
| Get the device specific interrupt active status [not for Cortex-M0, Cortex-M0+, or SC000].
uint32_t | NVIC_GetEnableIRQ (IRQn_Type IRQn)
| Get a device specific interrupt enable status.
uint32_t | NVIC_GetPendingIRQ (IRQn_Type IRQn)
| Get the pending device specific interrupt.
uint32_t | NVIC_GetPriority (IRQn_Type IRQn)
| Get the priority of an interrupt.
uint32_t | NVIC_GetPriorityGrouping (void)
| Read the priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].
uint32_t | NVIC_GetTargetState (IRQn_Type IRQn)
| Get Interrupt Target State.
uint32_t | NVIC_GetVector (IRQn_Type IRQn)
| Read Interrupt Vector [not for Cortex-M0, SC000].
void | NVIC_SetPendingIRQ (IRQn_Type IRQn)
| Set a device specific interrupt to pending.
void | NVIC_SetPriority (IRQn_Type IRQn, uint32_t priority)
| Set the priority for an interrupt.
void | NVIC_SetPriorityGrouping (uint32_t PriorityGroup)
| Set priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].
uint32_t | NVIC_SetTargetState (IRQn_Type IRQn)
| Set Interrupt Target State.
void | NVIC_SetVector (IRQn_Type IRQn, uint32_t vector)
| Modify Interrupt Vector [not for Cortex-M0, SC000].
void | NVIC_SystemReset (void)
| Reset the system.

## Description

Functions to access the Nested Vector Interrupt Controller (NVIC).

This section explains how to use interrupts and exceptions and access functions for the Nested Vector Interrupt Controller (NVIC).

Arm provides a template file startup_device for each supported compiler. The file must be adapted by the silicon vendor to include interrupt vectors for all device-specific interrupt handlers. Each interrupt handler is defined as a weak function to an dummy handler. These interrupt handlers can be used directly in application software without being adapted by the programmer.

The table below lists the core exception vectors of the various Cortex-M processors.

Exception Vector | Handler Function | IRQn Value | Armv6-M | Armv7-M | Armv8-M Baseline | Armv8-M Mainline | Armv8.1-M Mainline | Description
--- | --- | --- | --- | --- | --- | --- | --- | ---
NonMaskableInt_IRQn | NMI_Handler | -14 | √ | √ | √ | √ | √ | Non Maskable Interrupt
HardFault_IRQn | HardFault_Handler | -13 | √ | √ | √ | √ | √ | Hard Fault Interrupt
MemoryManagement_IRQn | MemManage_Handler | -12 | — | √ | — | √ | √ | Memory Management Interrupt
BusFault_IRQn | BusFault_Handler | -11 | — | √ | — | √ | √ | Bus Fault Interrupt
UsageFault_IRQn | UsageFault_Handler | -10 | — | √ | — | √ | √ | Usage Fault Interrupt
SecureFault_IRQn | SecureFault_Handler | -9 | — | — | √ | √ | √ | Secure Fault Interrupt
SVCall_IRQn | SVC_Handler | -5 | √ | √ | √ | √ | √ | SVC Interrupt
DebugMonitor_IRQn | DebugMon_Handler | -4 | — | √ | — | √ | √ | Debug Monitor Interrupt
PendSV_IRQn | PendSV_Handler | -2 | √ | √ | √ | √ | √ | Pend SV Interrupt
SysTick_IRQn | SysTick_Handler | -1 | √ | √ | √ | √ | √ | System Tick Interrupt

# Vector Table

The Vector Table defines the entry addresses of the processor exceptions and the device specific interrupts. It is typically located at the beginning of the program memory, however Using Interrupt Vector Remap it can be relocated to RAM. The symbol __Vectors is the address of the vector table in the startup code and the register SCB->VTOR holds the start address of the vector table.

An Armv8-M implementation with TrustZone provides two vector tables:

- vector table for Secure handlers
- vector table for Non-Secure handlers

Refer to Programmers Model with TrustZone for more information.

## Processor Exceptions

At the beginning of the vector table, the initial stack value and the exception vectors of the processor are defined. The vector table below shows the exception vectors of a Armv8-M Mainline processor. Other processor variants may have fewer vectors.

__Vectors DCD __initial_sp ; Top of Stack initialization
DCD Reset_Handler ; Reset Handler
DCD NMI_Handler ; NMI Handler
DCD HardFault_Handler ; Hard Fault Handler
DCD MemManage_Handler ; MPU Fault Handler
DCD BusFault_Handler ; Bus Fault Handler
DCD UsageFault_Handler ; Usage Fault Handler
DCD SecureFault_Handler ; Secure Fault Handler
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD SVC_Handler ; SVC Handler
DCD DebugMon_Handler ; Debug Monitor Handler
DCD 0 ; Reserved
DCD PendSV_Handler ; PendSV Handler
DCD SysTick_Handler ; SysTick Handler

## Device Specific Vectors

Following the processor exception vectors, the vector table contains also the device specific interrupt vectors.

; device specific interrupts
DCD WWDG_IRQHandler ; Window Watchdog
DCD PVD_IRQHandler ; PVD through EXTI Line detect
DCD TAMPER_IRQHandler ; Tamper

All device specific interrupts should have a default interrupt handler function that can be overwritten in user code. Below is an example for this default handler function.

Default_Handler PROC
EXPORT WWDG_IRQHandler [WEAK]
EXPORT PVD_IRQHandler [WEAK]
EXPORT TAMPER_IRQHandler [WEAK]
:
:
WWDG_IRQHandler
PVD_IRQHandler
TAMPER_IRQHandler
:
:
B .
ENDP

The user application may simply define an interrupt handler function by using the handler name as shown below.

void WWDG_IRQHandler(void)
{
...
}

# NVIC Function Usage

The code below shows the usage of various CMSIS NVIC functions with an LPC1700 device.

## Code Example 1

#include "LPC17xx.h"
uint32_t priorityGroup; /* Variables to store priority group and priority*/
uint32_t priority;
uint32_t preemptPriority;
uint32_t subPriority;
int main (void) {
NVIC_SetPriorityGrouping(5); /* Set priority group to 5:
Bit[7..6] preempt priority Bits,
Bit[5..3] subpriority Bits
(valid for five priority bits)*/
priorityGroup = NVIC_GetPriorityGrouping(); /* Get used priority grouping*/
priority = NVIC_EncodePriority(priorityGroup, 1, 6); /* Encode priority with 6 for subpriority and 1 for preempt priority
Note: priority depends on the used priority grouping*/
NVIC_SetPriority(UART0_IRQn, priority); /* Set new priority*/
priority = NVIC_GetPriority(UART0_IRQn); /* Retrieve priority again*/
NVIC_DecodePriority(priority, priorityGroup, &preemptPriority, &subPriority);
while(1);
}
NVIC_EncodePriority
uint32_t NVIC_EncodePriority(uint32_t PriorityGroup, uint32_t PreemptPriority, uint32_t SubPriority)
Encodes Priority [not for Cortex-M0, Cortex-M0+, or SC000].
NVIC_SetPriority
void NVIC_SetPriority(IRQn_Type IRQn, uint32_t priority)
Set the priority for an interrupt.
NVIC_GetPriorityGrouping
uint32_t NVIC_GetPriorityGrouping(void)
Read the priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].
NVIC_GetPriority
uint32_t NVIC_GetPriority(IRQn_Type IRQn)
Get the priority of an interrupt.
NVIC_DecodePriority
void NVIC_DecodePriority(uint32_t Priority, uint32_t PriorityGroup, uint32_t *pPreemptPriority, uint32_t *pSubPriority)
Decode the interrupt priority [not for Cortex-M0, Cortex-M0+, or SC000].
NVIC_SetPriorityGrouping
void NVIC_SetPriorityGrouping(uint32_t PriorityGroup)
Set priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].

## Code Example 2

#include "LPC17xx.h"
uint32_t active; /* Variable to store interrupt active state*/
void TIMER0_IRQHandler(void) { /* Timer 0 interrupt handler */
if (LPC_TIM0->IR & (1 << 0)) { /* Check if interrupt for match channel 0 occurred*/
LPC_TIM0->IR |= (1 << 0); /* Acknowledge interrupt for match channel 0 occurred*/
}
active = NVIC_GetActive(TIMER0_IRQn); /* Get interrupt active state of timer 0*/
}
int main (void) {
/* Set match channel register MR0 to 1 millisecond*/
LPC_TIM0->MR0 = (((SystemCoreClock / 1000) / 4) - 1); /* 1 ms?*/
LPC_TIM0->MCR = (3 << 0); /* Enable interrupt and reset for match channel MR0*/
NVIC_EnableIRQ(TIMER0_IRQn); /* Enable NVIC interrupt for timer 0*/
LPC_TIM0->TCR = (1 << 0); /* Enable timer 0*/
while(1);
}
NVIC_EnableIRQ
void NVIC_EnableIRQ(IRQn_Type IRQn)
Enable a device specific interrupt.
NVIC_GetActive
uint32_t NVIC_GetActive(IRQn_Type IRQn)
Get the device specific interrupt active status [not for Cortex-M0, Cortex-M0+, or SC000].
SystemCoreClock
uint32_t SystemCoreClock
Variable to hold the system core clock value.
Definition: ref_system_init.txt:68

# NVIC API Virtualization

The CMSIS-Core has provisions for overriding NVIC APIs as required for implementing secure systems that control access to peripherals and related interrupts. These overrides allow an operating system to control the access privileges of application code to critical interrupts.

The NVIC function virtualization is enabled with the following #define symbols:

- CMSIS_NVIC_VIRTUAL enables overriding the CMSIS-Core (Cortex-M) NVIC functions.
- CMSIS_VECTAB_VIRTUAL enables overriding the CMSIS-Core (Cortex-M) interrupt vector table access functions.

## Macro Definition Documentation

## ◆ CMSIS_NVIC_VIRTUAL

#define CMSIS_NVIC_VIRTUAL

Virtualization of the NVIC API.

When CMSIS_NVIC_VIRTUAL is defined, the NVIC access functions in the table below must be implemented for virtualizing NVIC access. These functions should be implemented in a separate source module. The original CMSIS-Core __NVIC functions are always available independent of CMSIS_NVIC_VIRTUAL.

NVIC Access Functions | CMSIS-Core Functions
--- | ---
NVIC_EnableIRQ | __NVIC_EnableIRQ
NVIC_GetEnableIRQ | __NVIC_GetEnableIRQ
NVIC_DisableIRQ | __NVIC_DisableIRQ
NVIC_GetPendingIRQ | __NVIC_GetPendingIRQ
NVIC_SetPendingIRQ | __NVIC_SetPendingIRQ
NVIC_ClearPendingIRQ | __NVIC_ClearPendingIRQ
NVIC_GetActive | __NVIC_GetActive
NVIC_SetPriority | __NVIC_SetPriority
NVIC_GetPriority | __NVIC_GetPriority
NVIC_SetPriorityGrouping | __NVIC_SetPriorityGrouping
NVIC_GetPriorityGrouping | __NVIC_GetPriorityGrouping

## ◆ CMSIS_VECTAB_VIRTUAL

#define CMSIS_VECTAB_VIRTUAL

Virtualization of interrupt vector table access functions.

When CMSIS_NVIC_VIRTUAL is defined, the functions in the table below must be replaced to virtualize the API access functions to the interrupt vector table. The NVIC vector table API should be implemented in a separate source module. This allows, for example, alternate implementations to relocate the vector table from flash to RAM on the first vector table update.

The original CMSIS-Core functions are always available, but prefixed with __NVIC.

Interrupt Vector Table Access | CMSIS-Core Functions
--- | ---
NVIC_GetVector | __NVIC_GetVector
NVIC_SetVector | __NVIC_SetVector

## Enumeration Type Documentation

## ◆ IRQn_Type

enum IRQn_Type

Definition of IRQn numbers.

The core exception enumeration names for IRQn values are defined in the Device Header File <Device.h>.

- Negative IRQn values represent processor core exceptions (internal interrupts).
- Positive IRQn values represent device-specific exceptions (external interrupts).
- The first device-specific interrupt has the IRQn value 0.

The table below describes the core exception names and their availability in various Cortex-M cores.

Enumerator
NonMaskableInt_IRQn | Exception 2: Non Maskable Interrupt.
HardFault_IRQn | Exception 3: Hard Fault Interrupt.
MemoryManagement_IRQn | Exception 4: Memory Management Interrupt [not on Cortex-M0 variants].
BusFault_IRQn | Exception 5: Bus Fault Interrupt [not on Cortex-M0 variants].
UsageFault_IRQn | Exception 6: Usage Fault Interrupt [not on Cortex-M0 variants].
SecureFault_IRQn | Exception 7: Secure Fault Interrupt [only on Armv8-M].
SVCall_IRQn | Exception 11: SVC Interrupt.
DebugMonitor_IRQn | Exception 12: Debug Monitor Interrupt [not on Cortex-M0 variants].
PendSV_IRQn | Exception 14: Pend SV Interrupt [not on Cortex-M0 variants].
SysTick_IRQn | Exception 15: System Tick Interrupt.
WWDG_STM_IRQn | Device Interrupt 0: Window WatchDog Interrupt.
PVD_STM_IRQn | Device Interrupt 1: PVD through EXTI Line detection Interrupt.

## Function Documentation

## ◆ NVIC_ClearPendingIRQ()

void NVIC_ClearPendingIRQ | ( | IRQn_Type | IRQn | ) |

Clear a device specific interrupt from pending.

This function removes the pending state of the specified device specific interrupt IRQn. IRQn cannot be a negative number.

Parameters

  [in] | IRQn | Interrupt number

Remarks
  - IRQn must not be negative.
  - The registers that control the status of interrupts are called SETPEND and CLRPEND.
  - An interrupt can have the status pending though it is not active.

See also
  - NVIC_SetPendingIRQ; NVIC_GetPendingIRQ
  - Cortex-M Generic User Guides

## ◆ NVIC_ClearTargetState()

uint32_t NVIC_ClearTargetState | ( | IRQn_Type | IRQn | ) |

Clear Interrupt Target State.

Clears the interrupt target field in the non-secure NVIC when in secure state.

Parameters

  [in] | IRQn | External interrupt number. Value cannot be negative.

Returns
  - 0 if interrupt is assigned to Secure
  - 1 if interrupt is assigned to Non Secure

Remarks
  - Only available for Armv8-M in secure state.

See also
  - NVIC_GetTargetState; NVIC_SetTargetState;

## ◆ NVIC_DecodePriority()

void NVIC_DecodePriority | ( | uint32_t | Priority,
|  | uint32_t | PriorityGroup,
|  | uint32_t * | pPreemptPriority,
|  | uint32_t * | pSubPriority
| ) |  |

Decode the interrupt priority [not for Cortex-M0, Cortex-M0+, or SC000].

This function decodes an interrupt priority value with the priority group PriorityGroup to preemptive priority value pPreemptPriority and subpriority value pSubPriority. In case of a conflict between priority grouping and available priority bits (__NVIC_PRIO_BITS) the smallest possible priority group is set.

Parameters

  [in] | Priority | Priority
  [in] | PriorityGroup | Priority group
  [out] | *pPreemptPriority | Preemptive priority value (starting from 0)
  [out] | *pSubPriority | Subpriority value (starting from 0)

Remarks
  - not for Cortex-M0, Cortex-M0+, or SC000.

See also
  - NVIC_EncodePriority; NVIC_GetPriority; NVIC_GetPriorityGrouping;
  - Cortex-M Generic User Guides

## ◆ NVIC_DisableIRQ()

void NVIC_DisableIRQ | ( | IRQn_Type | IRQn | ) |

Disable a device specific interrupt.

This function disables the specified device specific interrupt IRQn. IRQn cannot be a negative value.

Parameters

  [in] | IRQn | Number of the external interrupt to disable

Remarks
  - IRQn must not be negative.
  - The registers that control the enabling and disabling of interrupts are called SETENA and CLRENA.

See also
  - NVIC_EnableIRQ
  - Cortex-M Generic User Guides

## ◆ NVIC_EnableIRQ()

void NVIC_EnableIRQ | ( | IRQn_Type | IRQn | ) |

Enable a device specific interrupt.

This function enables the specified device specific interrupt IRQn. IRQn cannot be a negative value.

Parameters

  [in] | IRQn | Interrupt number

Remarks
  - IRQn must not be negative.
  - The registers that control the enabling and disabling of interrupts are called SETENA and CLRENA.
  - The number of supported interrupts depends on the implementation of the chip designer and can be read form the Interrupt Controller Type Register (ICTR) in granularities of 32:
    ICTR[4:0]
    - 0 - 32 interrupts supported
    - 1 - 64 interrupts supported
    - ...

See also
  - NVIC_DisableIRQ; SCnSCB_Type;
  - Cortex-M Generic User Guides

## ◆ NVIC_EncodePriority()

uint32_t NVIC_EncodePriority | ( | uint32_t | PriorityGroup,
|  | uint32_t | PreemptPriority,
|  | uint32_t | SubPriority
| ) |  |

Encodes Priority [not for Cortex-M0, Cortex-M0+, or SC000].

This function encodes the priority for an interrupt with the priority group PriorityGroup, preemptive priority value PreemptPriority, and subpriority value SubPriority. In case of a conflict between priority grouping and available priority bits (__NVIC_PRIO_BITS) the smallest possible priority group is set.

Parameters

  [in] | PriorityGroup | Priority group
  [in] | PreemptPriority | Preemptive priority value (starting from 0)
  [in] | SubPriority | Subpriority value (starting from 0)

Returns
  Encoded priority for the interrupt

Remarks
  - not for Cortex-M0, Cortex-M0+, or SC000.

See also
  - NVIC_DecodePriority; NVIC_SetPriority;
  - Cortex-M Generic User Guides

## ◆ NVIC_GetActive()

uint32_t NVIC_GetActive | ( | IRQn_Type | IRQn | ) |

Get the device specific interrupt active status [not for Cortex-M0, Cortex-M0+, or SC000].

This function reads the Interrupt Active Register (NVIC_IABR0-NVIC_IABR7) in NVIC and returns the active bit of the interrupt IRQn.

Parameters

  [in] | IRQn | Interrupt number

Returns
  - 0 Interrupt is not active
  - 1 Interrupt is active, or active and pending

Remarks
  - not for Cortex-M0, Cortex-M0+, or SC000.
  - IRQn must not be negative.
  - Each external interrupt has an active status bit. When the processor starts the interrupt handler the bit is set to 1 and cleared when the interrupt return is executed.
  - When an ISR is preempted and the processor executes another interrupt handler, the previous interrupt is still defined as active.

See also
  - Cortex-M Generic User Guides

## ◆ NVIC_GetEnableIRQ()

uint32_t NVIC_GetEnableIRQ | ( | IRQn_Type | IRQn | ) |

Get a device specific interrupt enable status.

This function returns the interrupt enable status for the specified device specific interrupt IRQn. IRQn cannot be a negative value.

Parameters

  [in] | IRQn | Interrupt number

Returns
  - 0 Interrupt is not enabled
  - 1 Interrupt is enabled

Remarks
  - IRQn must not be negative.
  - The registers that control the enabling and disabling of interrupts are called SETENA and CLRENA.

See also
  - NVIC_EnableIRQ; NVIC_DisableIRQ;
  - Cortex-M Generic User Guides

## ◆ NVIC_GetPendingIRQ()

uint32_t NVIC_GetPendingIRQ | ( | IRQn_Type | IRQn | ) |

Get the pending device specific interrupt.

This function returns the pending status of the specified device specific interrupt IRQn.

Parameters

  [in] | IRQn | Interrupt number

Returns
  - 0 Interrupt is not pending
  - 1 Interrupt is pending

Remarks
  - IRQn must not be negative.
  - The registers that control the status of interrupts are called SETPEND and CLRPEND.

See also
  - NVIC_SetPendingIRQ; NVIC_ClearPendingIRQ
  - Cortex-M Generic User Guides

## ◆ NVIC_GetPriority()

uint32_t NVIC_GetPriority | ( | IRQn_Type | IRQn | ) |

Get the priority of an interrupt.

This function reads the priority for the specified interrupt IRQn. IRQn can can specify any device specific interrupt, or processor exception.

The returned priority value is automatically aligned to the implemented priority bits of the microcontroller.

Parameters

  [in] | IRQn | Interrupt number

Returns
  Interrupt priority

Remarks
  - Each external interrupt has an associated priority-level register.
  - Unimplemented bits are read as zero.

See also
  - NVIC_SetPriority; NVIC_GetPriorityGrouping; __get_BASEPRI;
  - Cortex-M Generic User Guides

## ◆ NVIC_GetPriorityGrouping()

uint32_t NVIC_GetPriorityGrouping | ( | void |  | ) |

Read the priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].

This function returns the priority grouping (flag PRIGROUP in AIRCR[10:8]).

Returns
  Priority grouping field

Remarks
  - not for Cortex-M0, Cortex-M0+, or SC000.
  - By default, priority group setting is zero.

See also
  - NVIC_SetPriorityGrouping; NVIC_GetPriority; SCB_Type
  - Cortex-M Generic User Guides

## ◆ NVIC_GetTargetState()

uint32_t NVIC_GetTargetState | ( | IRQn_Type | IRQn | ) |

Get Interrupt Target State.

Reads the interrupt target field from the non-secure NVIC when in secure state.

Parameters

  [in] | IRQn | External interrupt number. Value cannot be negative.

Returns
  - 0 if interrupt is assigned to Secure
  - 1 if interrupt is assigned to Non Secure

Remarks
  - Only available for Armv8-M in secure state.

See also
  - NVIC_ClearTargetState; NVIC_SetTargetState;

## ◆ NVIC_GetVector()

uint32_t NVIC_GetVector | ( | IRQn_Type | IRQn | ) |

Read Interrupt Vector [not for Cortex-M0, SC000].

This function allows to read the address of an interrupt handler function.

Parameters

  [in] | IRQn | Interrupt number

Returns
  Address of interrupt handler function

Remarks
  - For using this function with Cortex-M0+ processor based devices, the SBC->VTOR register must be implemented.

See also
  - NVIC_SetVector
  - Cortex-M Generic User Guides

## ◆ NVIC_SetPendingIRQ()

void NVIC_SetPendingIRQ | ( | IRQn_Type | IRQn | ) |

Set a device specific interrupt to pending.

This function sets the pending bit for the specified device specific interrupt IRQn. IRQn cannot be a negative value.

Parameters

  [in] | IRQn | Interrupt number

Remarks
  - IRQn must not be negative.
  - The registers that control the status of interrupts are called SETPEND and CLRPEND.

See also
  - NVIC_GetPendingIRQ; NVIC_ClearPendingIRQ
  - Cortex-M Generic User Guides

## ◆ NVIC_SetPriority()

void NVIC_SetPriority | ( | IRQn_Type | IRQn,
|  | uint32_t | priority
| ) |  |

Set the priority for an interrupt.

Sets the priority for the interrupt specified by IRQn.IRQn can can specify any device specific interrupt, or processor exception. The priority specifies the interrupt priority value, whereby lower values indicate a higher priority. The default priority is 0 for every interrupt. This is the highest possible priority.

The priority cannot be set for every core interrupt. HardFault and NMI have a fixed (negative) priority that is higher than any configurable exception or interrupt.

Parameters

  [in] | IRQn | Interrupt Number
  [in] | priority | Priority to set

Remarks
  - The number of priority levels is configurable and depends on the implementation of the chip designer. To determine the number of bits implemented for interrupt priority-level registers, write 0xFF to one of the priority-level register, then read back the value. For example, if the minimum number of 3 bits have been implemented, the read-back value is 0xE0.
  - Writes to unimplemented bits are ignored.
  - For Cortex-M0:
    - Dynamic switching of interrupt priority levels is not supported. The priority level of an interrupt should not be changed after it has been enabled.
    - Supports 0 to 192 priority levels.
    - Priority-level registers are 2 bit wide, occupying the two MSBs. Each Interrupt Priority Level Register is 1-byte wide.
  - For Cortex-M3, Cortex-M4, and Cortex-M7:
    - Dynamic switching of interrupt priority levels is supported.
    - Supports 0 to 255 priority levels.
    - Priority-level registers have a maximum width of 8 bits and a minimum of 3 bits. Each register can be further divided into preempt priority level and subpriority level.

See also
  - NVIC_GetPriority; NVIC_SetPriorityGrouping; __set_BASEPRI;
  - Cortex-M Generic User Guides

## ◆ NVIC_SetPriorityGrouping()

void NVIC_SetPriorityGrouping | ( | uint32_t | PriorityGroup | ) |

Set priority grouping [not for Cortex-M0, Cortex-M0+, or SC000].

The function sets the priority grouping PriorityGroup using the required unlock sequence. PriorityGroup is assigned to the field PRIGROUP (register AIRCR[10:8]). This field determines the split of group priority from subpriority. Only values from 0..7 are used. In case of a conflict between priority grouping and available priority bits (__NVIC_PRIO_BITS), the smallest possible priority group is set.

Parameters

  [in] | PriorityGroup | Priority group

Remarks
  - not for Cortex-M0, Cortex-M0+, or SC000.
  - By default, priority group setting is zero.

See also
  - NVIC_GetPriorityGrouping; NVIC_SetPriority; SCB_Type
  - Cortex-M Generic User Guides

## ◆ NVIC_SetTargetState()

uint32_t NVIC_SetTargetState | ( | IRQn_Type | IRQn | ) |

Set Interrupt Target State.

Sets the interrupt target field in the non-secure NVIC when in secure state.

Parameters

  [in] | IRQn | External interrupt number. Value cannot be negative.

Returns
  - 0 if interrupt is assigned to Secure
  - 1 if interrupt is assigned to Non Secure

Remarks
  - Only available for Armv8-M in secure state.

See also
  - NVIC_ClearTargetState; NVIC_GetTargetState;

## ◆ NVIC_SetVector()

void NVIC_SetVector | ( | IRQn_Type | IRQn,
|  | uint32_t | vector
| ) |  |

Modify Interrupt Vector [not for Cortex-M0, SC000].

This function allows to change the address of an interrupt handler function.

Parameters

  [in] | IRQn | Interrupt number
  [in] | vector | Address of new interrupt handler function

Remarks
  - Usage of this function requires vector relocation to RAM. Refer to Using Interrupt Vector Remap for more information.

- For using this function with Cortex-M0+ processor based devices, the SBC->VTOR register must be implemented.

See also
  - NVIC_GetVector
  - Cortex-M Generic User Guides

## ◆ NVIC_SystemReset()

void NVIC_SystemReset | ( | void |  | ) |

Reset the system.

This function requests a system reset by setting the SYSRESETREQ flag in the AIRCR register.

Remarks
  - In most microcontroller designs, setting the SYSRESETREQ flag resets the processor and most parts of the system, but should not affect the debug system.

See also
  - Cortex-M Generic User Guides