get_irq_priority

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A lightweight RT-Thread utility package for inspecting Cortex®-M NVIC interrupt priorities from the MSH shell. It can display enabled interrupts, sort them by IRQ number or priority, and update the priority of a selected IRQ at runtime.

• 📘 Online Documentation: https://wdfk-prog.space/rt-thread-get_irq_priority/

1. Overview

get_irq_priority is a debugging-oriented package for RT-Thread. It is designed to:

• list currently enabled interrupts;
• show IRQ number, IRQ name, Pending/Active state, and priority;
• print the output sorted by IRQ number or interrupt priority;
• temporarily change the priority of a selected IRQ from the command line.

The output style is intentionally close to the NVIC view in the Keil debugger, which makes it useful for cross-checking runtime behavior against IDE/debugger expectations.

2. Current Support Scope

Based on the uploaded source package, the project currently includes IRQ name tables for the following STM32 families:

• STM32F0
• STM32F1
• STM32F2
• STM32F3
• STM32F4
• STM32F7
• STM32G0
• STM32G4
• STM32H7
• STM32L0
• STM32L4

Validation examples already present in the repository screenshots

• STM32H750
• STM32F747
• STM32F429
• STM32F103

3. How It Works

The package reads NVIC runtime information through CMSIS APIs, including:

• NVIC_GetEnableIRQ()
• NVIC_GetPendingIRQ()
• NVIC_GetActive()
• NVIC_GetPriority()
• NVIC_SetPriority()

The output covers two categories:

1. Cortex-M exception types
   Such as NonMaskableInt_IRQn, HardFault_IRQn, MemoryManagement_IRQn, PendSV_IRQn, and SysTick_IRQn.

2. External interrupts (IRQs)
   That is, device interrupts defined by the chip IRQ table.

With the default command, the package first prints exception-type entries and then prints enabled IRQs.

4. Repository Layout

get_irq_priority
├── figures/                 # Screenshots used by the documentation
├── inc/                     # IRQ name tables for different STM32 families
│   ├── irq_stm32f0.h
│   ├── irq_stm32f1.h
│   ├── irq_stm32f2.h
│   ├── irq_stm32f3.h
│   ├── irq_stm32f4.h
│   ├── irq_stm32f7.h
│   ├── irq_stm32g0.h
│   ├── irq_stm32g4.h
│   ├── irq_stm32h7.h
│   ├── irq_stm32l0.h
│   └── irq_stm32l4.h
├── src/
│   └── get_irq.c            # Core implementation and MSH entry
├── Kconfig                  # Package configuration entry
├── LICENSE                  # LGPL-2.1
├── SConscript               # RT-Thread build script
└── readme.md                # Original README (recommended to rename to README.md)

5. Dependencies

Before using this package, make sure the project meets the following requirements:

• RT-Thread MSH / FinSH is enabled;
• a console device is correctly registered;
• the target platform is an STM32 Cortex-M device;
• CMSIS and chip-specific IRQ definitions are available in the build.

Kconfig constraint

The current Kconfig contains:

depends on SOC_FAMILY_STM32

So the online package menu entry is only exposed when the STM32 SoC family condition is satisfied.

6. Integration

Option 1: Manual integration

1. Download or copy the get_irq_priority package directory.
2. Place it into a manageable location in your project.
3. Add src/get_irq.c to the build.
4. Make sure the expected chip macro is defined, such as SOC_SERIES_STM32H7 or SOC_SERIES_STM32F4.
5. Rebuild the project.

Option 2: Enable from RT-Thread Env / Studio

The package can be enabled from:

RT-Thread online packages -> miscellaneous packages -> get_irq_priority

If SOC_FAMILY_STM32 is not selected correctly, the package may not appear in the menu. In that case, check the BSP SoC/Kconfig setup first.

7. Command Reference

The package registers the following shell command:

nvic_irq

Supported forms are listed below.

7.1 Default mode

nvic_irq

Behavior:

• prints Cortex-M exception-type information first;
• then prints the currently enabled external interrupts;
• IRQ entries are listed in ascending IRQ-number order.

This is the most complete view and is useful for a quick NVIC inspection.

7.2 Sort by IRQ number

nvic_irq num

Behavior:

• prints enabled external interrupts only;
• sorts them by ascending IRQ number.

7.3 Sort by priority

nvic_irq priority

Behavior:

• prints enabled external interrupts only;
• sorts them by priority from low to high, following the wording and implementation used by the source code.

Note
In real projects, you should interpret this together with the priority encoding rules of your Cortex-M target, because “smaller numeric value” and “higher logical priority” are not the same statement.

7.4 Set IRQ priority

nvic_irq set <IRQn> <priority>

Example:

nvic_irq set 25 3

Behavior:

• directly calls NVIC_SetPriority(IRQn, priority) at runtime;
• affects the current runtime state only;
• does not persist the change back into static project configuration.

Parameter constraints:

• IRQn must be within the current IRQ table range;
• priority must be in the range 0 ~ 15.

8. Output Columns

The command header looks like this:

num IRQ name                       E P A Priotity
--- --------                       - - - --------

Column meanings:

• num: IRQ number
• IRQ name: interrupt name
• E: Enable state
• P: Pending state
• A: Active state
• Priotity: priority value reported by the current implementation

Note
The source code and existing README both use the spelling Priotity. If the project is maintained further, it would be better to normalize it to Priority.

9. Sorting Semantics

Number-based output

Both nvic_irq and nvic_irq num ultimately print enabled IRQs in IRQ-number order.

Priority-based output

nvic_irq priority caches the priority of enabled IRQs, sorts that buffer, and then prints the results.

This makes it useful for:

• checking which interrupts currently share the same priority;
• reviewing preemption ordering;
• diagnosing timing issues or priority inversions.

10. Typical Use Cases

• verifying that critical peripheral IRQs are enabled after BSP initialization;
• checking priority assignments for DMA, UART, TIM, EXTI, and similar interrupts;
• comparing runtime NVIC state against the Keil debugger view;
• verifying whether later driver initialization accidentally overwrote IRQ priorities;
• temporarily adjusting priorities to observe behavior changes.

11. Figures and Examples

11.1 Principle and UI mapping

CMSIS/NVIC access principle:

Comparison with the Keil NVIC view:

11.2 Generic command examples

Default output example:

Priority-sorted output example:

Set-priority example:

11.3 Platform validation screenshots

STM32H750

Default query:

Priority-sorted query:

Set priority:

STM32F747

Default query:

Priority-sorted query:

STM32F429

Default query:

Priority-sorted query:

STM32F103

Default query:

Priority-sorted query:

12. Notes and Limitations

• The package depends on console output; make sure a console device is available.
• The online-package entry currently depends on SOC_FAMILY_STM32.
• IRQ name tables are maintained per STM32 family in the current implementation.
• The set command changes priorities at runtime; it is not a replacement for BSP/driver initialization code.
• If MSH / FinSH is not enabled, the command-line interface will not be available.
• Disabled IRQs are not printed in the IRQ list.

13. License

This project is licensed under LGPL-2.1. See the LICENSE file for details.

14. Maintenance

• Maintainer: wdfk-prog
• Repository: https://github.com/wdfk-prog/rt-thread-get_irq_priority

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