微處理器 - NXP LPC2103 - Assembly - WatchDog Timer(WDT)

參考資料：
https://www.keil.com/dd/docs/datashts/philips/user_manual_lpc2101_2102_2103.pdf

暫存器




main.s

    .equ IODIR,  0xe0028008
    .equ IOCLR,  0xe002800c
    .equ IOSET,  0xe0028004
    .equ PCON,   0xe01fc0c0
    .equ WDMOD,  0xe0000000
    .equ WDTC,   0xe0000004
    .equ WDFEED, 0xe0000008
 
    .text
    .align 2
    .global _start
_start:    b reset
_undef:    b .
_swi:      b .
_pabort:   b .
_dabort:   b .
_reserved: b .
_irq:      b .
_fiq:      b .

reset:
    ldr r0, =WDTC
    ldr r1, =500000
    str r1, [r0]

    ldr r0, =WDMOD
    ldr r1, =0x03
    str r1, [r0]

    ldr r0, =WDFEED
    ldr r1, =0xaa
    ldr r2, =0x55
    str r1, [r0]
    str r2, [r0]

    ldr r0, =IODIR
    ldr r1, =(1 << 22)
    str r1, [r0]
loop: 
    ldr r0, =IOCLR
    ldr r1, =(1 << 22)
    str r1, [r0]
    ldr r4, =10000
1:
    nop
    subs r4, r4, #1
    bne 1b

    ldr r0, =IOSET
    ldr r1, =(1 << 22)
    str r1, [r0]
    ldr r4, =10000
1:
    nop
    subs r4, r4, #1
    bne 1b
    b loop
    .end

觀察LED的變化