ARM7启动代码.docx

1、ARM7启动代码SAMSUNG公司推出的16、32位RISC处理器S3C44BOX为手持设备和一般类型应用提供了高性价比和高性能的微控制器解决方案。为了降低成本，S3C44BOX提供了丰富的内置部件，包括8KBCache和内部SRAM,LCD控制器，带自动握手的2通道UART，4通道DMA，系统管理器（片选逻辑，FP/EDO/SDRAM控制器）。带PWM功能的5通道定时器和一个内部定时器，I/O端口，RTC，8通道10位ADC，IIC_BUS 接口，IIS_BUS接口，同步SIO接口和PLL倍频器。这里是一般的44BINIT.S，即其启动代码如下 ：; *; * NAME : 44BINIT.

2、S *; * Version : 10.JAn.2003 *; * Description: *; * C start up codes *; * Configure memory, Initialize ISR ,stacks *; * Initialize C-variables *; * Fill zeros into zero-initialized C-variables *; *GET .incoption.sGET .incmemcfg.s;Interrupt ControlINTPND EQU 0x01e00004INTMOD EQU 0x01e00008INTMSK EQU

3、0x01e0000cI_ISPR EQU 0x01e00020I_CMST EQU 0x01e0001c;Watchdog timerWTCON EQU 0x01d30000;Clock ControllerPLLCON EQU 0x01d80000CLKCON EQU 0x01d80004LOCKTIME EQU 0x01d8000c;Memory ControllerREFRESH EQU 0x01c80024;Pre-defined constantsUSERMODE EQU 0x10FIQMODE EQU 0x11IRQMODE EQU 0x12SVCMODE EQU 0x13ABOR

4、TMODE EQU 0x17UNDEFMODE EQU 0x1bMODEMASK EQU 0x1fNOINT EQU 0xc0;check if tasm.exe is used.GBLL THUMBCODE CONFIG = 16THUMBCODE SETL TRUECODE32|THUMBCODE SETL FALSE THUMBCODECODE32 ;for start-up code for Thumb modeMACRO$HandlerLabel HANDLER $HandleLabel$HandlerLabelsub sp,sp,#4 ;decrement sp(to store

5、jump address)stmfd sp!,r0 ;PUSH the work register to stack(lr doest push because it return to original address)ldr r0,=$HandleLabel;load the address of HandleXXX to r0ldr r0,r0 ;load the contents(service routine start address) of HandleXXXstr r0,sp,#4 ;store the contents(ISR) of HandleXXX to stackld

6、mfd sp!,r0,pc ;POP the work register and pc(jump to ISR)MENDIMPORT |Image$RO$Limit| ; End of ROM code (=start of ROM data)IMPORT |Image$RW$Base| ; Base of RAM to initialiseIMPORT |Image$ZI$Base| ; Base and limit of areaIMPORT |Image$ZI$Limit| ; to zero initialiseIMPORT Main ; The main entry of mon p

7、rogramAREA Init,CODE,READONLYENTRYb ResetHandler ;for debugb HandlerUndef ;handlerUndefb HandlerSWI ;SWI interrupt handlerb HandlerPabort ;handlerPAbortb HandlerDabort ;handlerDAbortb . ;handlerReservedb HandlerIRQb HandlerFIQ;*IMPORTANT NOTE*;If the H/W vectored interrutp mode is enabled, The above

8、 two instructions should;be changed like below, to work-around with H/W bug of S3C44B0X interrupt controller.; b HandlerIRQ - subs pc,lr,#4; b HandlerIRQ - subs pc,lr,#4VECTOR_BRANCHldr pc,=HandlerEINT0 ;mGA H/W interrupt vector tableldr pc,=HandlerEINT1 ;ldr pc,=HandlerEINT2 ;ldr pc,=HandlerEINT3 ;

9、ldr pc,=HandlerEINT4567 ;ldr pc,=HandlerTICK ;mGAb .b .ldr pc,=HandlerZDMA0 ;mGBldr pc,=HandlerZDMA1 ;ldr pc,=HandlerBDMA0 ;ldr pc,=HandlerBDMA1 ;ldr pc,=HandlerWDT ;ldr pc,=HandlerUERR01 ;mGBb .b .ldr pc,=HandlerTIMER0 ;mGCldr pc,=HandlerTIMER1 ;ldr pc,=HandlerTIMER2 ;ldr pc,=HandlerTIMER3 ;ldr pc,

10、=HandlerTIMER4 ;ldr pc,=HandlerTIMER5 ;mGCb .b .ldr pc,=HandlerURXD0 ;mGDldr pc,=HandlerURXD1 ;ldr pc,=HandlerIIC ;ldr pc,=HandlerSIO ;ldr pc,=HandlerUTXD0 ;ldr pc,=HandlerUTXD1 ;mGDb .b .ldr pc,=HandlerRTC ;mGKAb . ;b . ;b . ;b . ;b . ;mGKAb .b .ldr pc,=HandlerADC ;mGKBb . ;b . ;b . ;b . ;b . ;mGKB

11、b .b .ldr pc,=EnterPWDNEXPORT outportwoutportw strh r0, r1mov pc, lrEXPORT outportloutportl str r0, r1mov pc, lrEXPORT inportwinportw ldrh r0, r0mov pc, lrEXPORT inportlinportl ldr r0, r0mov pc, lrLTORGHandlerFIQ HANDLER HandleFIQHandlerIRQ HANDLER HandleIRQHandlerUndef HANDLER HandleUndefHandlerSWI

12、 HANDLER HandleSWIHandlerDabort HANDLER HandleDabortHandlerPabort HANDLER HandlePabortHandlerADC HANDLER HandleADCHandlerRTC HANDLER HandleRTCHandlerUTXD1 HANDLER HandleUTXD1HandlerUTXD0 HANDLER HandleUTXD0HandlerSIO HANDLER HandleSIOHandlerIIC HANDLER HandleIICHandlerURXD1 HANDLER HandleURXD1Handle

13、rURXD0 HANDLER HandleURXD0HandlerTIMER5 HANDLER HandleTIMER5HandlerTIMER4 HANDLER HandleTIMER4HandlerTIMER3 HANDLER HandleTIMER3HandlerTIMER2 HANDLER HandleTIMER2HandlerTIMER1 HANDLER HandleTIMER1HandlerTIMER0 HANDLER HandleTIMER0HandlerUERR01 HANDLER HandleUERR01HandlerWDT HANDLER HandleWDTHandlerB

14、DMA1 HANDLER HandleBDMA1HandlerBDMA0 HANDLER HandleBDMA0HandlerZDMA1 HANDLER HandleZDMA1HandlerZDMA0 HANDLER HandleZDMA0HandlerTICK HANDLER HandleTICKHandlerEINT4567 HANDLER HandleEINT4567HandlerEINT3 HANDLER HandleEINT3HandlerEINT2 HANDLER HandleEINT2HandlerEINT1 HANDLER HandleEINT1HandlerEINT0 HAN

15、DLER HandleEINT0;One of the following two routines can be used for non-vectored interrupt.IsrIRQ ;using I_ISPR register.sub sp,sp,#4 ;reserved for PCstmfd sp!,r8-r9;IMPORTANT CAUTION;if I_ISPC isnt used properly, I_ISPR can be 0 in this routine.ldr r9,=I_ISPRldr r9,r9mov r8,#0x00movs r9,r9,lsr #1bcs

16、 %F1add r8,r8,#4b %B01ldr r9,=HandleADCadd r9,r9,r8ldr r9,r9str r9,sp,#8ldmfd sp!,r8-r9,pc;*;* START *;*ResetHandlerldr r0,=WTCON ;watch dog disableldr r1,=0x0str r1,r0ldr r0,=INTMSKldr r1,=0x07ffffff ;all interrupt disablestr r1,r0;*;* Set clock control registers *;*ldr r0,=LOCKTIMEldr r1,=800 ; co

17、unt = t_lock * Fin (t_lock=200us, Fin=4MHz) = 800str r1,r0 PLLONSTARTldr r0,=PLLCON ;temporary setting of PLLldr r1,=(M_DIV12)+(P_DIV top of initialised datacmp r0, r1 ; Check that they are differentbeq %F10cmp r1, r3 ; Copy init dataldrcc r2, r0, #4 ;- LDRCC r2, r0 + ADD r0, r0, #4strcc r2, r1, #4

18、;- STRCC r2, r1 + ADD r1, r1, #4bcc %B01ldr r1, =|Image$ZI$Limit| ; Top of zero init segmentmov r2, #02cmp r3, r1 ; Zero initstrcc r2, r3, #4bcc %B2 :LNOT:THUMBCODEBL Main ;Dont use main()B . THUMBCODE ;for start-up code for Thumb modeorr lr,pc,#1bx lrCODE16bl Main ;Dont use main()b .CODE32;*;* The

19、function for initializing stack *;*InitStacks;Dont use DRAM,such as stmfd,ldmfd.;SVCstack is initialized before;Under toolkit ver 2.50, msr cpsr,r1 can be used instead of msr cpsr_cxsf,r1mrs r0,cpsrbic r0,r0,#MODEMASKorr r1,r0,#UNDEFMODE|NOINTmsr cpsr_cxsf,r1 ;UndefModeldr sp,=UndefStackorr r1,r0,#A

20、BORTMODE|NOINTmsr cpsr_cxsf,r1 ;AbortModeldr sp,=AbortStackorr r1,r0,#IRQMODE|NOINTmsr cpsr_cxsf,r1 ;IRQModeldr sp,=IRQStackorr r1,r0,#FIQMODE|NOINTmsr cpsr_cxsf,r1 ;FIQModeldr sp,=FIQStackbic r0,r0,#MODEMASK|NOINTorr r1,r0,#SVCMODEmsr cpsr_cxsf,r1 ;SVCModeldr sp,=SVCStack;USER mode is not initializ

21、ed.mov pc,lr ;The LR register may be not valid for the mode changes.;*;* The function for entering power down mode *;*;void EnterPWDN(int CLKCON);EnterPWDNmov r2,r0 ;r0=CLKCONldr r0,=REFRESHldr r3,r0mov r1, r3orr r1, r1, #0x400000 ;self-refresh enablestr r1, r0nop ;Wait until self-refresh is issued.

22、 May not be needed.nop ;If the other bus master holds the bus, .nop ; mov r0, r0nopnopnopnop;enter POWERDN modeldr r0,=CLKCONstr r2,r0;wait until enter SL_IDLE,STOP mode and until wake-upmov r0,#0xff0 subs r0,r0,#1bne %B0;exit from DRAM/SDRAM self refresh mode.ldr r0,=REFRESHstr r3,r0mov pc,lrLTORGSMRDATA DATA;*;* Memory configuration has to be optimized for best performance *;* The following parameter is not optimized. *;*;* memory access cycle parameter strategy *; 1) Even FP-DRAM, EDO setting has more late fetch point by half-clock; 2) The memory settings,here, are made the