2440中使用看门狗定时器作为普通定时器
好吧，看s3c2440的看门狗看了好长时间，因为看门一般很少使用，所以我就想让看门狗作为一般的定时器来触发中断，简单一点，就做一个LED灯的定时闪烁。看了好多资料，百度、数据手册中英文版、学习板光盘资料。。。。。。确实是一个纠结的过程，但是最后懂了收获到的也是满满的快乐。
我要说的：
1、不能全相信手册，手册上说看门狗计时器作为一般定时器时，应使能中断并且禁止看门狗定时器。然而实践证明是不对的；应该使能中断并且使能看门狗定时器，同时禁止看门狗的复位功能。主程序中的rWTCON |= (1<<5)|(1<<2);就是见证。
2、清中断简单粗暴就行，不需要那么多的函数。
rSRCPND = 0x1<<9;
rSUBSRCPND = 0x1<<13;
rINTPND = 0x1<<9;2440init.s
GET option.inc
GET memcfg.inc
GET 2440addr.inc
BIT_SELFREFRESH EQU (1<<22)
;Pre-defined constants
USERMODE EQU 0x10
FIQMODE EQU 0x11
IRQMODE EQU 0x12
SVCMODE EQU 0x13
ABORTMODE EQU 0x17
UNDEFMODE EQU 0x1b
MODEMASK EQU 0x1f
NOINT EQU 0xc0
;The location of stacks
UserStack EQU (_STACK_BASEADDRESS-0x3800) ;0x33ff4800 ~
SVCStack EQU (_STACK_BASEADDRESS-0x2800) ;0x33ff5800 ~
UndefStack EQU (_STACK_BASEADDRESS-0x2400) ;0x33ff5c00 ~
AbortStack EQU (_STACK_BASEADDRESS-0x2000) ;0x33ff6000 ~
IRQStack EQU (_STACK_BASEADDRESS-0x1000) ;0x33ff7000 ~
FIQStack EQU (_STACK_BASEADDRESS-0x0) ;0x33ff8000 ~
;Check if tasm.exe(armasm -16 ...@ADS 1.0) is used.
GBLL THUMBCODE
[ {CONFIG} = 16
THUMBCODE SETL {TRUE}
CODE32
|
THUMBCODE SETL {FALSE}
]
MACRO
MOV_PC_LR
[ THUMBCODE
bx lr
|
mov pc,lr
]
MEND
MACRO
MOVEQ_PC_LR
[ THUMBCODE
bxeq lr
|
moveq pc,lr
]
MEND
MACRO
$HandlerLabel HANDLER $HandleLabel
$HandlerLabel
sub sp,sp,#4 ;decrement sp(to store jump address)
stmfd sp!,{r0} ;PUSH the work register to stack(lr does not push because it return to original address)
ldr r0,=$HandleLabel;load the address of HandleXXX to r0
ldr r0,[r0] ;load the contents(service routine start address) of HandleXXX
str r0,[sp,#4] ;store the contents(ISR) of HandleXXX to stack
ldmfd sp!,{r0,pc} ;POP the work register and pc(jump to ISR)
MEND
IMPORT Main ; The main entry of mon program
AREA Init,CODE,READONLY
ENTRY
EXPORT __ENTRY
__ENTRY
ResetEntry
;1)The code, which converts to Big-endian, should be in little endian code.
;2)The following little endian code will be compiled in Big-Endian mode.
; The code byte order should be changed as the memory bus width.
;3)The pseudo instruction,DCD can not be used here because the linker generates error.
ASSERT :DEF:ENDIAN_CHANGE
[ ENDIAN_CHANGE
ASSERT :DEF:ENTRY_BUS_WIDTH
[ ENTRY_BUS_WIDTH=16
andeq r14,r7,r0,lsl #20 ;DCD 0x0007ea00
]
[ ENTRY_BUS_WIDTH=8
streq r0,[r0,-r10,ror #1] ;DCD 0x070000ea
]
|
b ResetHandler
]
b HandlerUndef ;handler for Undefined mode
b HandlerSWI ;handler for SWI interrupt
b HandlerPabort ;handler for PAbort
b HandlerDabort ;handler for DAbort
b . ;reserved
b HandlerIRQ ;handler for IRQ interrupt
b HandlerFIQ ;handler for FIQ interrupt
;@0x20
; b EnterPWDN ; Must be @0x20.
HandlerFIQ HANDLER HandleFIQ
HandlerIRQ HANDLER HandleIRQ
HandlerUndef HANDLER HandleUndef
HandlerSWI HANDLER HandleSWI
HandlerDabort HANDLER HandleDabort
HandlerPabort HANDLER HandlePabort
IsrIRQ
sub sp,sp,#4 ;reserved for PC
stmfd sp!,{r8-r9}
ldr r9,=INTOFFSET
ldr r9,[r9]
ldr r8,=HandleEINT0
add r8,r8,r9,lsl #2
ldr r8,[r8]
str r8,[sp,#8]
ldmfd sp!,{r8-r9,pc}
LTORG
;=======
; ENTRY
;=======
ResetHandler
ldr r0,=WTCON ;watch dog disable
ldr r1,=0x0
str r1,[r0]
ldr r0,=INTMSK
ldr r1,=0xffffffff ;all interrupt disable
str r1,[r0]
ldr r0,=INTSUBMSK
ldr r1,=0x7fff ;all sub interrupt disable
str r1,[r0]
;To reduce PLL lock time, adjust the LOCKTIME register.
ldr r0,=LOCKTIME
ldr r1,=0xffffff
str r1,[r0]
[ PLL_ON_START
; Added for confirm clock divide. for 2440.
; Setting value Fclk:Hclk:Pclk
ldr r0,=CLKDIVN
ldr r1,=CLKDIV_VAL ; 0=1:1:1, 1=1:1:2, 2=1:2:2, 3=1:2:4, 4=1:4:4, 5=1:4:8, 6=1:3:3, 7=1:3:6.
str r1,[r0]
;program has not been copied, so use these directly,
[ CLKDIV_VAL>1 ; means Fclk:Hclk is not 1:1.
mrc p15,0,r0,c1,c0,0
orr r0,r0,#0xc0000000;R1_nF:OR:R1_iA
mcr p15,0,r0,c1,c0,0
|
mrc p15,0,r0,c1,c0,0
bic r0,r0,#0xc0000000;R1_iA:OR:R1_nF
mcr p15,0,r0,c1,c0,0
]
;Configure UPLL
ldr r0,=UPLLCON
ldr r1,=((U_MDIV<<12)+(U_PDIV<<4)+U_SDIV)
str r1,[r0]
nop ; Caution: After UPLL setting, at least 7-clocks delay must be inserted for setting hardware be completed.
nop
nop
nop
nop
nop
nop
;Configure MPLL
ldr r0,=MPLLCON
ldr r1,=((M_MDIV<<12)+(M_PDIV<<4)+M_SDIV) ;Fin=16.9344MHz
str r1,[r0]
]
;Check if the boot is caused by the wake-up from SLEEP mode.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;; When EINT0 is pressed, Clear SDRAM
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; check if EIN0 button is pressed
1 bl InitStacks
;===========================================================
; Setup IRQ handler
ldr r0,=HandleIRQ ;This routine is needed
ldr r1,=IsrIRQ ;if there is not 'subs pc,lr,#4' at 0x18, 0x1c
str r1,[r0]
[ :LNOT:THUMBCODE
bl Main ;Do not use main() because ......
b .
]
[ THUMBCODE ;for start-up code for Thumb mode
orr lr,pc,#1
bx lr
CODE16
bl Main ;Do not use main() because ......
b .
CODE32
]
;function initializing stacks
InitStacks
;Do not use DRAM,such as stmfd,ldmfd......
;SVCstack is initialized before
;Under toolkit ver 2.5, 'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'
mrs r0,cpsr
bic r0,r0,#MODEMASK
orr r1,r0,#UNDEFMODE|NOINT
msr cpsr_cxsf,r1 ;UndefMode
ldr sp,=UndefStack ; UndefStack=0x33FF_5C00
orr r1,r0,#ABORTMODE|NOINT
msr cpsr_cxsf,r1 ;AbortMode
ldr sp,=AbortStack ; AbortStack=0x33FF_6000
orr r1,r0,#IRQMODE|NOINT
msr cpsr_cxsf,r1 ;IRQMode
ldr sp,=IRQStack ; IRQStack=0x33FF_7000
orr r1,r0,#FIQMODE|NOINT
msr cpsr_cxsf,r1 ;FIQMode
ldr sp,=FIQStack ; FIQStack=0x33FF_8000
bic r0,r0,#MODEMASK|NOINT
orr r1,r0,#SVCMODE
msr cpsr_cxsf,r1 ;SVCMode
ldr sp,=SVCStack ; SVCStack=0x33FF_5800
;USER mode has not be initialized.
mov pc,lr
;The LR register will not be valid if the current mode is not SVC mode.
;===========================================================
;=====================================================================
; Clock division test
; Assemble code, because VSYNC time is very short
;=====================================================================
ALIGN
AREA RamData, DATA, READWRITE
^ _ISR_STARTADDRESS ; _ISR_STARTADDRESS=0x33FF_FF00
HandleReset # 4
HandleUndef # 4
HandleSWI # 4
HandlePabort # 4
HandleDabort # 4
HandleReserved # 4
HandleIRQ # 4
HandleFIQ # 4
;Do not use the label 'IntVectorTable',
;The value of IntVectorTable is different with the address you think it may be.
;IntVectorTable
;@0x33FF_FF20
HandleEINT0 # 4
HandleEINT1 # 4
HandleEINT2 # 4
HandleEINT3 # 4
HandleEINT4_7 # 4
HandleEINT8_23 # 4
HandleCAM # 4 ; Added for 2440.
HandleBATFLT # 4
HandleTICK # 4
HandleWDT # 4
HandleTIMER0 # 4
HandleTIMER1 # 4
HandleTIMER2 # 4
HandleTIMER3 # 4
HandleTIMER4 # 4
HandleUART2 # 4
;@0x33FF_FF60
HandleLCD # 4
HandleDMA0 # 4
HandleDMA1 # 4
HandleDMA2 # 4
HandleDMA3 # 4
HandleMMC # 4
HandleSPI0 # 4
HandleUART1 # 4
HandleNFCON # 4 ; Added for 2440.
HandleUSBD # 4
HandleUSBH # 4
HandleIIC # 4
HandleUART0 # 4
HandleSPI1 # 4
HandleRTC # 4
HandleADC # 4
;@0x33FF_FFA0
END#define _IRQ_BASEADDRESS 0x33ffff00
/*#define pISR_RESET (*(unsigned *)(_IRQ_BASEADDRESS+0x0))
#define pISR_UNDEF (*(unsigned *)(_IRQ_BASEADDRESS+0x4))
#define pISR_SWI (*(unsigned *)(_IRQ_BASEADDRESS+0x8))
#define pISR_PABORT (*(unsigned *)(_IRQ_BASEADDRESS+0xc))
#define pISR_DABORT (*(unsigned *)(_IRQ_BASEADDRESS+0x10))
#define pISR_RESERVED (*(unsigned *)(_IRQ_BASEADDRESS+0x14))
#define pISR_IRQ (*(unsigned *)(_IRQ_BASEADDRESS+0x18))
#define pISR_FIQ (*(unsigned *)(_IRQ_BASEADDRESS+0x1c))*/
#define pISR_WDT (*(unsigned *)(_IRQ_BASEADDRESS+0x44))
#define U32 unsigned int
//GPBIO（使用GPB5）
#define rGPBCON (*(unsigned *) 0x56000010)
#define rGPBDAT ( *(unsigned *) 0x56000014)
#define rGPBUP ( *(unsigned *) 0x56000018)
//UART0
#define rUTRSTAT0 (*(volatile unsigned *)0x50000010) //UART 0 Tx/Rx status
#define rULCON0 (*(volatile unsigned *)0x50000000) //UART 0 Line control
#define rUCON0 (*(volatile unsigned *)0x50000004) //UART 0 Control
#define rUFCON0 (*(volatile unsigned *)0x50000008) //UART 0 FIFO control
#define rUBRDIV0 (*(volatile unsigned *)0x50000028) //UART 0 Baud rate divisor
#define WrUTXH0(ch) (*(volatile unsigned char *)0x50000020)=(unsigned char)(ch)
//WDT
#define rWTCON (*(volatile unsigned *)0x53000000)
#define rWTDAT (*(volatile unsigned *)0x53000004)
#define rWTCNT (*(volatile unsigned *)0x53000008)
//INTRRUPT
#define rSRCPND (*(volatile unsigned *)0x4A000000)
#define rINTMOD (*(volatile unsigned *)0x4A000004)
#define rINTMSK (*(volatile unsigned *)0x4A000008)
#define rPRIORITY (*(volatile unsigned *)0x4A00000c)
#define rINTPND (*(volatile unsigned *)0x4A000010)
#define rINTOFFSET (*(volatile unsigned *)0x4A000014)
#define rSUBSRCPND (*(volatile unsigned *)0x4A000018)
#define rINTSUBMSK (*(volatile unsigned *)0x4A00001C)
#define prescaler_value 127
#define clock_select 3
#define BIT_WDT_AC97 (1<<9)
#define BIT_WDT (1<<13)
#define BIT_AC97 (1<<14)
#define EnableIrq(bit) rINTMSK &= ~(bit)
#define DisableIrq(bit) rINTMSK |= (bit)
#define EnableSubIrq(bit) rINTSUBMSK &= ~(bit)
#define DisableSubIrq(bit) rINTSUBMSK |= (bit)
main.c
#include "2440addr.h"
void delay(int a)
{
int k;
for(k=0;k