Cortex-M3(NXP LPC 1788) 啓動代碼

時間 2019-11-20

標籤 cortex m3 nxp lpc 啓動代碼简体版

原文原文鏈接

startup_LPC177x_8x.s啓動代碼分析。html

參考資料：app

;/*****************************************************************************
; * @file:    startup_LPC177x_8x.s
; * @purpose: CMSIS Cortex-M3 Core Device Startup File
; *           for the NXP LPC177x_8x Device Series 
; * @version: V1.20
; * @date:    07. October 2010
; *------- <<< Use Configuration Wizard in Context Menu >>> ------------------
; *
; * Copyright (C) 2010 ARM Limited. All rights reserved.
; * ARM Limited (ARM) is supplying this software for use with Cortex-M3
; * processor based microcontrollers.  This file can be freely distributed
; * within development tools that are supporting such ARM based processors.
; *
; * 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.
; *
; *****************************************************************************/


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

Stack_Size      EQU     0x00002000                         ;開闢一塊大小爲Stack_Size的棧空間

                AREA    STACK, NOINIT, READWRITE, ALIGN=3  ;AREA僞指令：用於定義代碼段和數據段，後跟屬性標號。
 ;其中「READWRITE」表示可讀寫，「READONLY」只讀屬性。
 ;根據LPC1788的數據手冊描述的存儲介質，可知可讀寫段保持在SRAM區，
 ;起始地址爲0x1000 0000，代碼中的堆棧保存在SRAM空間。
 ;只讀段保存在Flash區，起始地址爲0x0000 0000，代碼中的中斷向量表保存在Flash空間。 
 ;所以能夠總結出，在0x0000 0000 存放的是棧頂的地址__initial_sp（即0x1000 0200），
 ;在0x0000 0004 存放的是Reset_Handler的地址。
Stack_Mem       SPACE   Stack_Size
__initial_sp                                               ;標號__initial_sp指向棧頂位置


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

Heap_Size       EQU     0x00005000                         ;定義堆空間大小爲Heap_Size

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


;創建中斷向量表Vectors，cortex-M3規定起始地址必須存放棧頂地址即__initial_sp，緊接着存放復位入口地址，
;這樣內核復位後就會自動從起始地址的下32位取出復位地址執行復位中斷服務函數。

                PRESERVE8                                  ;指定了如下代碼爲8字節對齊
                THUMB                                      ;指定了如下代碼爲THUMB指令集


; Vector Table Mapped to Address 0 at Reset

                AREA    RESET, DATA, READONLY              ;聲明RESET數據段
                EXPORT  __Vectors                          ;導出向量表標號，EXPORT做用至關於C語言中的extern

__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     OSPendSV                  ; used by uCOS-II
                DCD     SysTick_Handler           ; SysTick Handler'used by uCOS-II

                ; External Interrupts
                DCD     WDT_IRQHandler            ; 16: Watchdog Timer
                DCD     TIMER0_IRQHandler         ; 17: Timer0
                DCD     TIMER1_IRQHandler         ; 18: Timer1
                DCD     TIMER2_IRQHandler         ; 19: Timer2
                DCD     TIMER3_IRQHandler         ; 20: Timer3
                DCD     UART0_IRQHandler          ; 21: UART0
                DCD     UART1_IRQHandler          ; 22: UART1
                DCD     UART2_IRQHandler          ; 23: UART2
                DCD     UART3_IRQHandler          ; 24: UART3
                DCD     PWM1_IRQHandler           ; 25: PWM1
                DCD     I2C0_IRQHandler           ; 26: I2C0
                DCD     I2C1_IRQHandler           ; 27: I2C1
                DCD     I2C2_IRQHandler           ; 28: I2C2
                DCD     SPIFI_IRQHandler          ; 29: SPIFI
                DCD     SSP0_IRQHandler           ; 30: SSP0
                DCD     SSP1_IRQHandler           ; 31: SSP1
                DCD     PLL0_IRQHandler           ; 32: PLL0 Lock (Main PLL)
                DCD     RTC_IRQHandler            ; 33: Real Time Clock
                DCD     EINT0_IRQHandler          ; 34: External Interrupt 0
                DCD     EINT1_IRQHandler          ; 35: External Interrupt 1
                DCD     EINT2_IRQHandler          ; 36: External Interrupt 2
                DCD     EINT3_IRQHandler          ; 37: External Interrupt 3
                DCD     ADC_IRQHandler            ; 38: A/D Converter
                DCD     BOD_IRQHandler            ; 39: Brown-Out Detect
                DCD     USB_IRQHandler            ; 40: USB
                DCD     CAN_IRQHandler            ; 41: CAN
                DCD     DMA_IRQHandler            ; 42: General Purpose DMA
                DCD     I2S_IRQHandler            ; 43: I2S
                DCD     ENET_IRQHandler           ; 44: Ethernet
                DCD     MCI_IRQHandler            ; 45: SD/MMC card I/F
                DCD     MCPWM_IRQHandler          ; 46: Motor Control PWM
                DCD     QEI_IRQHandler            ; 47: Quadrature Encoder Interface
                DCD     PLL1_IRQHandler           ; 48: PLL1 Lock (USB PLL)
                DCD        USBActivity_IRQHandler    ; 49: USB Activity interrupt to wakeup
                DCD        CANActivity_IRQHandler    ; 50: CAN Activity interrupt to wakeup
                DCD        UART4_IRQHandler          ; 51: UART4
                DCD        SSP2_IRQHandler           ; 52: SSP2
                DCD        LCD_IRQHandler            ; 53: LCD
                DCD        GPIO_IRQHandler           ; 54: GPIO
                DCD        PWM0_IRQHandler           ; 55: PWM0
                DCD        EEPROM_IRQHandler         ; 56: EEPROM

;這段代碼是NXP公司的LPC1700系列的MCU特有的一段代碼，其餘公司的Cortex-M3 MCU的啓動程序是沒有這段代碼的。

;這段代碼是指定LPC1700的CRP加密級別的代碼段，芯片上電後會自動讀取這一地址的值以肯定加密方式.
;其中CRP_Key = 0xffffffff爲不加密（0級加密），CRP_Key = 0x12345678爲1級加密，CRP_Key = 0x87654321爲2級加密，
;CRP_Key = 0x43218765爲3級加密（最高級加密），3級加密將會禁止全部的ISP指令，也就是說，芯片將不能讀寫、不能擦除。

                IF      :LNOT::DEF:NO_CRP
                AREA    |.ARM.__at_0x02FC|, CODE, READONLY
CRP_Key         DCD     0xFFFFFFFF
                ENDIF


                AREA    |.text|, CODE, READONLY


; Reset Handler

Reset_Handler   PROC
                EXPORT  Reset_Handler             [WEAK]    ;聲明Reset_Handler的全局性
                IMPORT  SystemInit                          ;復位後先調用SystemInit
                IMPORT  __main                              ;再調用__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
OSPendSV        PROC
                EXPORT  OSPendSV            [WEAK]
                B       .
                ENDP
SysTick_Handler PROC
                EXPORT  SysTick_Handler           [WEAK]
                B       .
                ENDP

Default_Handler PROC

                EXPORT  WDT_IRQHandler            [WEAK]
                EXPORT  TIMER0_IRQHandler         [WEAK]
                EXPORT  TIMER1_IRQHandler         [WEAK]
                EXPORT  TIMER2_IRQHandler         [WEAK]
                EXPORT  TIMER3_IRQHandler         [WEAK]
                EXPORT  UART0_IRQHandler          [WEAK]
                EXPORT  UART1_IRQHandler          [WEAK]
                EXPORT  UART2_IRQHandler          [WEAK]
                EXPORT  UART3_IRQHandler          [WEAK]
                EXPORT  PWM1_IRQHandler           [WEAK]
                EXPORT  I2C0_IRQHandler           [WEAK]
                EXPORT  I2C1_IRQHandler           [WEAK]
                EXPORT  I2C2_IRQHandler           [WEAK]
                EXPORT  SPIFI_IRQHandler          [WEAK]
                EXPORT  SSP0_IRQHandler           [WEAK]
                EXPORT  SSP1_IRQHandler           [WEAK]
                EXPORT  PLL0_IRQHandler           [WEAK]
                EXPORT  RTC_IRQHandler            [WEAK]
                EXPORT  EINT0_IRQHandler          [WEAK]
                EXPORT  EINT1_IRQHandler          [WEAK]
                EXPORT  EINT2_IRQHandler          [WEAK]
                EXPORT  EINT3_IRQHandler          [WEAK]
                EXPORT  ADC_IRQHandler            [WEAK]
                EXPORT  BOD_IRQHandler            [WEAK]
                EXPORT  USB_IRQHandler            [WEAK]
                EXPORT  CAN_IRQHandler            [WEAK]
                EXPORT  DMA_IRQHandler            [WEAK]
                EXPORT  I2S_IRQHandler            [WEAK]
                EXPORT  ENET_IRQHandler           [WEAK]
                EXPORT  MCI_IRQHandler            [WEAK]
                EXPORT  MCPWM_IRQHandler          [WEAK]
                EXPORT  QEI_IRQHandler            [WEAK]
                EXPORT  PLL1_IRQHandler           [WEAK]
                EXPORT  USBActivity_IRQHandler    [WEAK]
                EXPORT  CANActivity_IRQHandler    [WEAK]
                EXPORT  UART4_IRQHandler          [WEAK]
                EXPORT  SSP2_IRQHandler           [WEAK]
                EXPORT  LCD_IRQHandler            [WEAK]
                EXPORT  GPIO_IRQHandler           [WEAK]
                EXPORT  PWM0_IRQHandler           [WEAK]
                EXPORT  EEPROM_IRQHandler         [WEAK]

WDT_IRQHandler
TIMER0_IRQHandler
TIMER1_IRQHandler
TIMER2_IRQHandler
TIMER3_IRQHandler
UART0_IRQHandler
UART1_IRQHandler
UART2_IRQHandler
UART3_IRQHandler
PWM1_IRQHandler
I2C0_IRQHandler
I2C1_IRQHandler
I2C2_IRQHandler
SPIFI_IRQHandler            
SSP0_IRQHandler
SSP1_IRQHandler
PLL0_IRQHandler
RTC_IRQHandler
EINT0_IRQHandler
EINT1_IRQHandler
EINT2_IRQHandler
EINT3_IRQHandler
ADC_IRQHandler
BOD_IRQHandler
USB_IRQHandler
CAN_IRQHandler
DMA_IRQHandler
I2S_IRQHandler
ENET_IRQHandler
MCI_IRQHandler          
MCPWM_IRQHandler
QEI_IRQHandler
PLL1_IRQHandler
USBActivity_IRQHandler
CANActivity_IRQHandler
UART4_IRQHandler
SSP2_IRQHandler
LCD_IRQHandler
GPIO_IRQHandler
PWM0_IRQHandler
EEPROM_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

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

                ALIGN

                ENDIF


                END

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