Nucleus 實時操作系統中斷（下）

Nucleus RTOS兼容性

由于中斷在Nucleus SE中的實現方式與Nucleus rto截然不同，因此不應期望有特定的兼容性。Nucleus RTOS有一個本機/低級/高級中斷方案，這在某種程度上類似于Nucleus SE中的本機中斷和管理中斷。

低級和高級ISR

低級ISR

低級中斷服務程序（LISR）作為普通ISR執行，包括使用當前堆棧。Nucleus RTOS在調用LISR之前保存上下文，并在LISR返回后恢復上下文。因此，lisr可以用C編寫，并且可以調用其他C例程。然而，只有少數Nucleus RTOS服務可用于LISR。如果中斷處理需要額外的Nucleus RTOS服務，則必須激活高級中斷服務程序（HISR）。Nucleus RTOS支持多個lisr的嵌套。

高級ISR

HISR是動態創建和刪除的。每個HISR都有自己的堆棧空間和自己的控制塊。每個內存都由應用程序提供。當然，HISR必須在LISR激活之前創建。

由于HISR有自己的堆棧和控制塊，所以如果它試圖訪問已經被訪問的Nucleus RTOS數據結構，則可以暫時阻止HISR。

HISR有三個優先級。如果在處理低優先級HISR期間激活了高優先級HISR，則低優先級HISR被搶占的方式與任務被搶占的方式大致相同。相同優先級的hisr按照它們最初激活的順序執行。在恢復正常任務調度之前，將處理所有激活的HISR。

Nucleus RTOS中斷API調用

Nucleus RTOS有許多API調用來支持其中斷結構。這些都不是在Nucleus SE中實現的。

對于本機中斷，API調用提供以下功能：

控制（啟用/禁用）中斷（本地和全局）

設置中斷向量

對于低電平中斷：

向內核注冊一個低級ISR

對于高級中斷：

創建/刪除高級中斷

激活高級中斷

獲取應用程序中（當前）的高級中斷數

獲取指向所有高級中斷的控制塊的指針

獲取指向當前高級中斷控制塊的指針

獲取有關高級中斷的信息

全局控制中斷

此服務以獨立于任務的方式啟用或禁用中斷。因此，由該服務禁用的中斷將保持禁用狀態，直到隨后對此服務的調用啟用為止。

服務調用原型：

INT NU_Control_Interrupts(INT new_level);

參數：

new_level–系統的新中斷級別。菜單禁用中斷（禁用所有中斷）和菜單啟用中斷（啟用所有中斷）選項始終可用。根據體系結構，還可以使用其他選項。

返回：

此服務返回以前級別的已啟用中斷。

本地控制中斷

此服務以依賴于任務的方式啟用或禁用中斷。此服務將狀態寄存器更改為指定的值。狀態寄存器將被設置回下一個上下文開關上一次調用NU_Control_Interrupts（）時設置的值。

服務調用原型：

INT NU_Local_Control_Interrupts(INT new_level);

參數：

new_level–當前任務的新中斷級別。菜單禁用中斷（禁用所有中斷）和菜單啟用中斷（啟用所有中斷）選項始終可用。根據體系結構，還可以使用其他選項。

返回：

此服務返回以前級別的已啟用中斷。

設置中斷向量

此服務用自定義中斷服務例程（ISR）替換vector指定的中斷向量。

服務調用原型：

VOID *NU_Setup_Vector(INT vector, VOID *new);

參數：

vector–用于注冊中斷的中斷向量

新–ISR將在vector注冊

返回：

此服務返回一個指向先前在中斷向量上注冊的ISR的指針。

注冊LISR中斷

此服務將LISR函數與中斷向量相關聯。系統上下文在調用指定的LISR之前自動保存，并在LISR返回后恢復。

服務調用原型：

STATUS NU_Register_LISR(INT vector, VOID(*lisr_entry)(INT),

VOID (**old_lisr)(INT));

Parameters:

vector – the interrupt vector at which to register the interrupt

lisr_entry – the function to register at the vector; a value of NU_NULL clears the vector

old_lisr – the subroutine previously registered at the specified vector

Returns:

NU_SUCCESS – successful completion of the service

NU_INVALID_VECTOR – the specified vector is invalid

NU_NOT_REGISTERED – the vector is not currently registered as de-registration was specified by lisr_entry

NU_NO_MORE_LISRS – the maximum number of registered LISRs has been exceeded

Create a HISR

This service creates a High-Level Interrupt Service Routine (HISR).

Service call prototype:

STATUS NU_Create_HISR(NU_HISR *hisr, CHAR *name,

VOID (*hisr_entry)(VOID), OPTION priority, VOID *stack_pointer, UNSIGNED stack_size);
Parameters:

hisr – pointer to a user-supplied HISR control block

name – pointer to a 7-character, null-terminated name for the HISR

hisr_entry – the function entry point of the HISR

priority – there are three HISR priorities (0-2); priority 0 is the highest

stack_pointer – pointer to the HISR’s stack area

stack_size – number of bytes in the HISR stack

Returns:

NU_SUCCESS – successful completion of the service

NU_INVALID_HISR – the HISR control block pointer is NULL or is already in use

NU_INVALID_ENTRY – the HISR entry pointer is NULL

NU_INVALID_PRIORITY – the HISR priority is invalid

NU_INVALID_MEMORY – the stack pointer is NULL

NU_INVALID_SIZE – the stack size is too small

Delete a HISR

This service deletes a previously created HISR.

Service call prototype:

STATUS NU_Delete_HISR(NU_HISR *hisr);

Parameters:

hisr – pointer to a user-supplied HISR control block

Returns:

NU_SUCCESS – successful completion of the service

NU_INVALID_HISR – the HISR pointer is invalid

激活HISR

此服務將激活HISR。如果指定的HISR當前正在執行，則在當前執行完成之前不會處理此激活請求。每個激活請求執行一次HISR。

服務調用原型：

TATUS NU_Activate_HISR (NU_HISR *hisr);

Parameters:

hisr – pointer to the HISR control block

Returns:

NU_SUCCESS – successful completion of the service

NU_INVALID_HISR – the HISR control block pointer is not valid

Obtain the Number of HISRs in a System

This service returns the number of established HISRs. All created HISRs are considered established. Deleted HISRs are no longer considered established.

Service call prototype:

UNSIGNED NU_Established_HISRs(VOID);

Parameters:

none

Returns:

This service call returns the number of established HISRs in the system

Obtain Pointers to HISR Control Blocks

This service builds a sequential list of pointers to all established HISRs in the system.

Service call prototype:

UNSIGNED NU_HISR_Pointers(NU_HISR **pointer_list,

UNSIGNED maximum_pointers);

Parameters:

pointer_list – pointer to an array of NU_HISR pointers; this array will be filled with pointers of established HISRs in the system

maximum_pointers – the maximum number of NU_HISR pointers to place into the array; typically, this will be the size of the pointer_list array

Returns:

This service call returns the number of HISRS that are active in the system

Obtain a Pointer to the Current HISR

This service returns the currently executing HISR’s pointer.

Service call prototype:

NU_HISR *NU_Current_HISR_Pointer(VOID);

Parameters:

none

Returns:

This service call returns a pointer the currently executing HISR’s control block. If the caller is not an HISR, the value returned is NU_NULL .

Obtain Information About a HISR

This service returns various information about the specified HISR.

Service call prototype:

STATUS NU_HISR_Information(NU_HISR *hisr, char *name,

UNSIGNED *scheduled_count, DATA_ELEMENT *priority,

VOID **stack_base, UNSIGNED *stack_size,

UNSIGNED *minimum_stack);

Parameters:

HISR – pointer to the HISR

name – pointer to an 8-character destination area for the HISR’s name; this includes space for the null terminator

scheduled_count – pointer to a variable for holding the total number of times this HISR has been scheduled

priority – pointer to a variable for holding the HISR’s priority

stack_base – pointer to a pointer for holding the original stack pointer; this is the same pointer supplied during creation of the HISR

stack_size – pointer to a
variable for holding the total size of the HISR’s stack

minimum_stack – pointer to a variable for holding the minimum amount of available stack space detected during HISR execution

Returns:

NU_SUCCESS – successful completion of the service

NU_INVALID_HISR – the HISR pointer is invalid

API Calls from ISRs

API Calls from LISRs

A LISR may only make use of the following Nucleus RTOS services:

NU_Activate_HISR()

NU_Local_Control_Interrupts()

NU_Current_HISR_Pointer()

NU_Current_Task_Pointer()

NU_Retrieve_Clock()

API Calls from HISRs

HISRs are allowed access to most Nucleus RTOS services, with the
exception of self-suspension services. Additionally, since an HISR cannot
suspend on a Nucleus RTOS service, the “suspend” parameter must always be set to NU_NO_SUSPEND .

總結

以上是生活随笔為你收集整理的Nucleus 实时操作系统中断（下）的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。