S3C2440 gpio

WATCHDOG TIMER

原理图

手册

举例
start.S

.globl _start_start:/* 关看门狗 *//* 往WTCON(0x53000000)写0 */    ldr r0, =0x53000000    mov r1, #0    str r1, [r0] @ str, store, /* 设置GPFCON让GPF5作为输出引脚 */    ldr r1, =0x56000050    mov r0, #(1<<10)    str r0, [r1]/* 设置GPFDAT让GPF5输出0 */    ldr r1, =0x56000054    mov r0, #0    str r0, [r1]/* 无限循环 */halt:    b halt  

Makefile

led.bin: start.o    arm-linux-gnueabihf-ld -Ttext 0 -o led.elf start.o    arm-linux-gnueabihf-objcopy -O binary led.elf led.bin    arm-linux-gnueabihf-objdump -D led.elf > led.disstart.o : start.S    arm-linux-gnueabihf-gcc -o start.o start.S -cclean:    rm *.o led.elf led.bin led.dis