CMSIS-Core (Cortex-M): Startup File startup_<device>.s

| CMSIS-Core (Cortex-M) Version 5.0.2 CMSIS-Core support for Cortex-M processor-based devices

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Startup File startup_<device>.s

The Startup File startup_<device>.s contains:

- The reset handler which is executed after CPU reset and typically calls the SystemInit function.
- The setup values for the Main Stack Pointer (MSP).
- Exception vectors of the Cortex-M Processor with weak functions that implement default routines.
- Interrupt vectors that are device specific with weak functions that implement default routines.

The file exists for each supported toolchain and is the only tool-chain specific CMSIS file.

To adapt the file to a new device only the interrupt vector table needs to be extended with the device-specific interrupt handlers. The naming convention for the interrupt handler names are <interrupt_name>_IRQHandler. This table needs to be consistent with IRQn_Type that defines all the IRQ numbers for each interrupt.

Example:

The following example shows the extension of the interrupt vector table for the LPC1100 device family.

; External Interrupts
DCD WAKEUP0_IRQHandler ; 16+ 0: Wakeup PIO0.0
DCD WAKEUP1_IRQHandler ; 16+ 1: Wakeup PIO0.1
DCD WAKEUP2_IRQHandler ; 16+ 2: Wakeup PIO0.2
: :
: :
DCD EINT1_IRQHandler ; 16+30: PIO INT1
DCD EINT0_IRQHandler ; 16+31: PIO INT0
:
:
EXPORT WAKEUP0_IRQHandler [WEAK]
EXPORT WAKEUP1_IRQHandler [WEAK]
EXPORT WAKEUP2_IRQHandler [WEAK]
: :
: :
EXPORT EINT1_IRQHandler [WEAK]
EXPORT EINT0_IRQHandler [WEAK]
WAKEUP0_IRQHandler
WAKEUP1_IRQHandler
WAKEUP1_IRQHandler
:
:
EINT1_IRQHandler
EINT0_IRQHandler
B .

# startup_Device.s Template File

An ARM Compiler startup_Device.s Template File for an ARMv7-M processor like Cortex-M3 is shown below. The files for other compiler vendors differ slightly in the syntax, but not in the overall structure.

    ;/**************************************************************************//**
    ; * @file     startup_<Device>.s
    ; * @brief    CMSIS Cortex-M ARMv7-M based Core Device Startup File for
    ; *           Device <Device>
    ; * @version  V5.00
    ; * @date     02. March 2016
    ; ******************************************************************************/
    ;/*
    ; * Copyright (c) 2009-2016 ARM Limited. All rights reserved.
    ; *
    ; * SPDX-License-Identifier: Apache-2.0
    ; *
    ; * Licensed under the Apache License, Version 2.0 (the License); you may
    ; * not use this file except in compliance with the License.
    ; * You may obtain a copy of the License at
    ; *
    ; * www.apache.org/licenses/LICENSE-2.0
    ; *
    ; * Unless required by applicable law or agreed to in writing, software
    ; * distributed under the License is distributed on an AS IS BASIS, WITHOUT
    ; * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    ; * See the License for the specific language governing permissions and
    ; * limitations under the License.
    ; */
    ;/*

    ;//-------- <<< Use Configuration Wizard in Context Menu >>> ------------------
    ;*/

    ; <h> Stack Configuration
    ;   <o> Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>
    ; </h>

    Stack_Size      EQU     0x00000400

                    AREA    STACK, NOINIT, READWRITE, ALIGN=3
    Stack_Mem       SPACE   Stack_Size
    __initial_sp

    ; <h> Heap Configuration
    ;   <o>  Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
    ; </h>

    Heap_Size       EQU     0x00000100

                    AREA    HEAP, NOINIT, READWRITE, ALIGN=3
    __heap_base
    Heap_Mem        SPACE   Heap_Size
    __heap_limit

                    PRESERVE8
                    THUMB

    ; Vector Table Mapped to Address 0 at Reset

                    AREA    RESET, DATA, READONLY
                    EXPORT  __Vectors
                    EXPORT  __Vectors_End
                    EXPORT  __Vectors_Size

    __Vectors       DCD     __initial_sp              ; Top of Stack
                    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     0                         ; Reserved
                    DCD     0                         ; Reserved
                    DCD     0                         ; Reserved
                    DCD     0                         ; Reserved
                    DCD     SVC_Handler               ; SVCall Handler
                    DCD     DebugMon_Handler          ; Debug Monitor Handler
                    DCD     0                         ; Reserved
                    DCD     PendSV_Handler            ; PendSV Handler
                    DCD     SysTick_Handler           ; SysTick Handler

                    ; External Interrupts
    ; ToDo:  Add here the vectors for the device specific external interrupts handler
                    DCD     <DeviceInterrupt>_IRQHandler       ;  0: Default
    __Vectors_End

    __Vectors_Size  EQU     __Vectors_End - __Vectors

                    AREA    |.text|, CODE, READONLY

    ; Reset Handler

    Reset_Handler   PROC
                    EXPORT  Reset_Handler             [WEAK]
                    IMPORT  SystemInit
                    IMPORT  __main
                    LDR     R0, =SystemInit
                    BLX     R0
                    LDR     R0, =__main
                    BX      R0
                    ENDP

    ; Dummy Exception Handlers (infinite loops which can be modified)

    NMI_Handler\
                    PROC
                    EXPORT  NMI_Handler               [WEAK]
                    B       .
                    ENDP
    HardFault_Handler\
                    PROC
                    EXPORT  HardFault_Handler         [WEAK]
                    B       .
                    ENDP
    MemManage_Handler\
                    PROC
                    EXPORT  MemManage_Handler         [WEAK]
                    B       .
                    ENDP
    BusFault_Handler\
                    PROC
                    EXPORT  BusFault_Handler          [WEAK]
                    B       .
                    ENDP
    UsageFault_Handler\
                    PROC
                    EXPORT  UsageFault_Handler        [WEAK]
                    B       .
                    ENDP
    SVC_Handler\
                    PROC
                    EXPORT  SVC_Handler               [WEAK]
                    B       .
                    ENDP
    DebugMon_Handler\
                    PROC
                    EXPORT  DebugMon_Handler          [WEAK]
                    B       .
                    ENDP
    PendSV_Handler\
                    PROC
                    EXPORT  PendSV_Handler            [WEAK]
                    B       .
                    ENDP
    SysTick_Handler\
                    PROC
                    EXPORT  SysTick_Handler           [WEAK]
                    B       .
                    ENDP

    Default_Handler PROC
    ; ToDo:  Add here the export definition for the device specific external interrupts handler
                    EXPORT  <DeviceInterrupt>_IRQHandler         [WEAK]

    ; ToDo:  Add here the names for the device specific external interrupts handler
    <DeviceInterrupt>_IRQHandler
                    B       .
                    ENDP

                    ALIGN

    ; User Initial Stack & Heap

                    IF      :DEF:__MICROLIB

                    EXPORT  __initial_sp
                    EXPORT  __heap_base
                    EXPORT  __heap_limit

                    ELSE

                    IMPORT  __use_two_region_memory
                    EXPORT  __user_initial_stackheap

    __user_initial_stackheap PROC
                    LDR     R0, =  Heap_Mem
                    LDR     R1, =(Stack_Mem + Stack_Size)
                    LDR     R2, = (Heap_Mem +  Heap_Size)
                    LDR     R3, = Stack_Mem
                    BX      LR
                    ENDP

                    ALIGN

                    ENDIF

                    END