【正文】 Zero init */ strcc r2, [r3], 4 bcc F2 MRS r0, CPSR bic r0, r0, NOINT /* enable interrupt */ msr CPSR_cxsf, r0 jump to Main() bl Main bl . **************************************************** * The function for entering power down mode * **************************************************** void EnterPWDN(int CLKCON)。EnterPWDN: mov r2, r0 /* r0=CLKCON */ ldr r0, =REFRESH ldr r3, [r0] mov r1, r3 orr r1, r1, 0x400000 /* selfrefresh enable */ str r1, [r0] nop /* Wait until selfrefresh is issued. May not be needed. */ nop /* If the other bus master holds the bus, ... */ nop /* mov r0, r0 */ nop nop nop nop enter POWERDN mode ldr r0, =CLKCON str r2, [r0] wait until enter SL_IDLE,STOP mode and until wakeup ldr r0, =0x10U0: subs r0, r0, 1 bne U0 exit from DRAM/SDRAM self refresh mode. ldr r0, =REFRESH str r3, [r0] mov pc, lr ***************************************************************** * Memory configuration has to be optimized for best performance * * The following parameter is not optimized. * ***************************************************************** *** memory access cycle parameter strategy *** 1) Even FPDRAM, EDO setting has more late fetch point by halfclock 2) The memory settings,here, are made the safe parameters even at 66Mhz. 3) FPDRAM Parameters:tRCD=3 for tRAC, tcas=2 for pad delay, tcp=2 for bus load. 4) DRAM refresh rate is for 40Mhz. bank0 16bit BOOT ROM bank1 NandFlash(8bit)/IDE/USB/LCD bank2 No use bank3 16bit cs8900a bank4 No use bank5 No use bank6 16bit SDRAM bank7 No use .ltorgSMRDATA:.ifeq BUSWIDTH16 .long 0x11119102 /* Bank0=16bit BootRom(AT29C010A*2) :0x0 */.else .long 0x22222220 /* Bank0=OM[1:0], Bank1~Bank7=32bit */.endif .long ((B0_Tacs13)+(B0_Tcos11)+(B0_Tacc8)+(B0_Tcoh6)+(B0_Tah4)+(B0_Tacp2)+(B0_PMC)) /* GCS0 */ .long ((B1_Tacs13)+(B1_Tcos11)+(B1_Tacc8)+(B1_Tcoh6)+(B1_Tah4)+(B1_Tacp2)+(B1_PMC)) /* GCS1 */ .long ((B2_Tacs13)+(B2_Tcos11)+(B2_Tacc8)+(B2_Tcoh6)+(B2_Tah4)+(B2_Tacp2)+(B2_PMC)) /* GCS2 */ .long ((B3_Tacs13)+(B3_Tcos11)+(B3_Tacc8)+(B3_Tcoh6)+(B3_Tah4)+(B3_Tacp2)+(B3_PMC)) /* GCS3 */ .long ((B4_Tacs13)+(B4_Tcos11)+(B4_Tacc8)+(B4_Tcoh6)+(B4_Tah4)+(B4_Tacp2)+(B4_PMC)) /* GCS4 */ .long ((B5_Tacs13)+(B5_Tcos11)+(B5_Tacc8)+(B5_Tcoh6)+(B5_Tah4)+(B5_Tacp2)+(B5_PMC)) /* GCS5 */.ifc DRAM,BDRAMTYPE .long ((B6_MT15)+(B6_Trcd4)+(B6_Tcas3)+(B6_Tcp2)+(B6_CAN)) /* GCS6 check the MT value in */ .long ((B7_MT15)+(B7_Trcd4)+(B7_Tcas3)+(B7_Tcp2)+(B7_CAN)) /* GCS7 */.else .long ((B6_MT15)+(B6_Trcd2)+(B6_SCAN)) /* GCS6 */ .long ((B7_MT15)+(B7_Trcd2)+(B7_SCAN)) /* GCS7 */.endif .long ((REFEN23)+(TREFMD22)+(Trp20)+(Trc18)+(Tchr16)+REFCNT) /* REFRESH RFEN=1, TREFMD=0, trp=3clk, trc=5clk, tchr=3clk,count=1019 */ .long 0x10 /* SCLK power down mode, BANKSIZE 32M/32M */ .long 0x20 /* MRSR6 CL=2clk */ .long 0x20 /* MRSR7 *//**//* constant define *//**/ .equ UserStack, _ISR_STARTADDRESS0xf00 /* c7ff000 */ .equ SVCStack, _ISR_STARTADDRESS0xf00+256 /* c7ff100 */ .equ UndefStack, _ISR_STARTADDRESS0xf00+256*2 /* c7ff200 */ .equ AbortStack, _ISR_STARTADDRESS0xf00+256*3 /* c7ff300 */ .equ IRQStack, _ISR_STARTADDRESS0xf00+256*4 /* c7ff400 */ .equ FIQStack, _ISR_STARTADDRESS0xf00+256*5 /* c7ff500 */ .equ HandleReset, _ISR_STARTADDRESS /* c7fff00 */ .equ HandleUndef, _ISR_STARTADDRESS+4 .equ HandleSWI, _ISR_STARTADDRESS+4*2 .equ HandlePabort, _ISR_STARTADDRESS+4*3 .equ HandleDabort, _ISR_STARTADDRESS+4*4 .equ HandleReserved, _ISR_STARTADDRESS+4*5 .equ HandleIRQ, _ISR_STARTADDRESS+4*6 .equ HandleFIQ, _ISR_STARTADDRESS+4*7 .equ HandleADC, _ISR_STARTADDRESS+4*8 .equ HandleRTC, _ISR_STARTADDRESS+4*9 .equ HandleUTXD1, _ISR_STARTADDRESS+4*10 .equ HandleUTXD0, _ISR_STARTADDRESS+4*11 .equ HandleSIO, _ISR_STARTADDRESS+4*12 .equ HandleIIC, _ISR_STARTADDRESS+4*13 .equ HandleURXD1, _ISR_STARTADDRESS+4*14 .equ HandleURXD0, _ISR_STARTADDRESS+4*15 .equ HandleTIMER5, _ISR_STARTADDRESS+4*16 .equ HandleTIMER4, _ISR_STARTADDRESS+4*17 .equ HandleTIMER3, _ISR_STARTADDRESS+4*18 .equ HandleTIMER2, _ISR_STARTADDRESS+4*19 .equ HandleTIMER1, _ISR_STARTADDRESS+4*20 .equ HandleTIMER0, _ISR_STARTADDRESS+4*21 .equ HandleUERR01, _ISR_STARTADDRESS+4*22 .equ HandleWDT, _ISR_STARTADDRESS+4*23 .equ HandleBDMA1, _ISR_STARTADDRESS+4*24 .equ HandleBDMA0, _ISR_STARTADDRESS+4*25 .equ HandleZDMA1, _ISR_STARTADDRESS+4*26 .equ HandleZDMA0, _ISR_STARTADDRESS+4*27 .equ HandleTICK, _ISR_STARTADDRESS+4*28 .equ HandleEINT4567, _ISR_STARTADDRESS+4*29 .equ HandleEINT3, _ISR_STARTADDRESS+4*30 .equ HandleEINT2, _ISR_STARTADDRESS+4*31 .equ HandleEINT1, _ISR_STARTADDRESS+4*32 .equ HandleEINT0, _ISR_STARTADDRESS+4*33 /* 0xc7fff84 */ .end5總結(jié)與體會 在這次嵌入式課程設(shè)計中，我掌握了S3C44B0X處理器看門狗控制器的使用。了解了看門狗在嵌入式系統(tǒng)中的作用，由于嵌入式系統(tǒng)具有體積小、功耗低的特點，所以大多用于自動控制領(lǐng)域，環(huán)境的變化可能會導(dǎo)致程序運行出錯，通過看門狗可以使系統(tǒng)復(fù)位或中斷，從而避免了程序跑飛帶來的不必要的損失?？撮T狗在許多應(yīng)用開發(fā)中都會用到，如電子詞典，在電子詞典中需要看門狗能在系統(tǒng)產(chǎn)時間沒有響應(yīng)時對系統(tǒng)進(jìn)行重啟。通過課程設(shè)計，我對嵌入式相關(guān)應(yīng)用程序開發(fā)有了初步了解，也對ARM指令集有了進(jìn)一步的熟悉，對以后嵌入式的學(xué)習(xí)有很大的幫助。 參考文獻(xiàn)[1] [M].：~