CMSIS-CORE  Version 3.01
CMSIS-CORE support for Cortex-M processor-based devices
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

The startup_Device.s Template File for the Cortex-M3 and the ARMCC compiler 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# Core Device Startup File for
; *           Device <Device>
; * @version  V3.01
; * @date     06. March 2012
; *
; * @note
; * Copyright (C) 2012 ARM Limited. All rights reserved.
; *
; * @par
; * ARM Limited (ARM) is supplying this software for use with Cortex-M
; * processor based microcontrollers.  This file can be freely distributed
; * within development tools that are supporting such ARM based processors.
; *
; * @par
; * THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
; * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
; * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
; * ARM SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
; * CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
; *
; ******************************************************************************/
;/*
;//-------- <<< 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