在Keil uVision4中新建一个基于NXP1788的工程后,会提示添加启动汇编代码startup_LPC177x_8x.S。该文件进行从汇编到C语言运行环境的初始化工作。
- ;/*****************************************************************************
- ; * @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 0x00000200
- 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 0x00000400
- 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
- __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
- 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
- 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]
- 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
- 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
;/*****************************************************************************; * @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.; *; *****************************************************************************/;Stack Configuration; Stack_Size EQU 0x00000200 AREA STACK, NOINIT, READWRITE, ALIGN=3Stack_Mem SPACE Stack_Size__initial_sp;Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>; Heap Configuration; Heap_Size EQU 0x00000400 AREA HEAP, NOINIT, READWRITE, ALIGN=3__heap_baseHeap_Mem SPACE Heap_Size__heap_limit PRESERVE8 THUMB; Vector Table Mapped to Address 0 at Reset AREA RESET, DATA, READONLY EXPORT __Vectors__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 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 IF :LNOT::DEF:NO_CRP AREA |.ARM.__at_0x02FC|, CODE, READONLYCRP_Key DCD 0xFFFFFFFF ENDIF AREA |.text|, CODE, READONLY; Reset HandlerReset_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 . ENDPHardFault_Handler\ PROC EXPORT HardFault_Handler [WEAK] B . ENDPMemManage_Handler\ PROC EXPORT MemManage_Handler [WEAK] B . ENDPBusFault_Handler\ PROC EXPORT BusFault_Handler [WEAK] B . ENDPUsageFault_Handler\ PROC EXPORT UsageFault_Handler [WEAK] B . ENDPSVC_Handler PROC EXPORT SVC_Handler [WEAK] B . ENDPDebugMon_Handler\ PROC EXPORT DebugMon_Handler [WEAK] B . ENDPPendSV_Handler PROC EXPORT PendSV_Handler [WEAK] B . ENDPSysTick_Handler PROC EXPORT SysTick_Handler [WEAK] B . ENDPDefault_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_IRQHandlerTIMER0_IRQHandlerTIMER1_IRQHandlerTIMER2_IRQHandlerTIMER3_IRQHandlerUART0_IRQHandlerUART1_IRQHandlerUART2_IRQHandlerUART3_IRQHandlerPWM1_IRQHandlerI2C0_IRQHandlerI2C1_IRQHandlerI2C2_IRQHandlerSPIFI_IRQHandler SSP0_IRQHandlerSSP1_IRQHandlerPLL0_IRQHandlerRTC_IRQHandlerEINT0_IRQHandlerEINT1_IRQHandlerEINT2_IRQHandlerEINT3_IRQHandlerADC_IRQHandlerBOD_IRQHandlerUSB_IRQHandlerCAN_IRQHandlerDMA_IRQHandlerI2S_IRQHandlerENET_IRQHandlerMCI_IRQHandler MCPWM_IRQHandlerQEI_IRQHandlerPLL1_IRQHandlerUSBActivity_IRQHandlerCANActivity_IRQHandlerUART4_IRQHandlerSSP2_IRQHandlerLCD_IRQHandlerGPIO_IRQHandlerPWM0_IRQHandlerEEPROM_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 ENDHeap Size (in Bytes) <0x0-0xFFFFFFFF:8>;
程序完成如下内容的工作:
开辟一块大小为Stack_Size的栈空间;
标号__initial_sp指向栈顶位置;
定义堆空间大小为Heap_Size;
建立中断向量表Vectors,cortex-M3规定起始地址必须存放栈顶地址即__initial_sp,紧接着存放复位入口地址,这样内核复位后就会自动从起始地址的下32位取出复位地址执行复位中断服务函数。
Reset_Handler复位中断函数中先EXPORT声明Reset_Handler的全局性,然后分别执行外部的函数SystemInit和__main。
下面对汇编程序中的几个关键字做说明:
AREA伪指令:用于定义代码段和数据段,后跟属性标号。其中“READWRITE”表示可读写,“READONLY”只读属性。根据LPC1788的数据手册描述的存储介质,可知可读写段保持在SRAM区,起始地址为0x1000 0000,代码中的堆栈保存在SRAM空间。只读段保存在Flash区,起始地址为0x0000 0000,代码中的中断向量表保存在Flash空间。 因此可以总结出,在0x0000 0000 存放的是栈顶的地址__initial_sp(即0x1000 0200),在0x0000 0004 存放的是Reset_Handler的地址。
图1:LPC1788 地址映射
图2: debug中 0地址的值0x1000 0200 即栈顶地址, 0x0000 0004 地址值为0x0000 00F9(看反汇编可知该值 即Reset_Handler的入口如下图)。
DCD指令:开辟内存空间,中断向量表建立中使用相当于C语言中的函数指针,每个成员都是函数指针,指向各个中断服务函数。
自此分析了LPC1788的启动,主要包括堆栈初始化,和中断向量表的初始化。LPC1788有内部Flash,所以上点从内部Flash启动,内部Flash的起始地址为0x0000 0000,存放栈顶的地址0x1000 0200。 0x0000 0004存放复位中断的入口地址。LPC1788复位后,从0x0000 0004取出复位入口地址,执行中断复位函数,从而跳转到SystemInit和main C语言函数执行。