微處理器 - TI DM3730 (BeagleBoard-XM) - Assembly - LED

LED D6是連接到GPIO-149


GPIO-149是屬於GPIO5


GPIO5 Clock


Output


Data


main.s

    .global _start
 
    .equ CM_ICLKEN_PER, 0x48005010
    .equ GPIO5_OE,      0x49056034
    .equ GPIO5_DATAOUT, 0x4905603c
  
    .arm
    .text
_start:
    b reset
    b .
    b .
    b .
    b .
    b .
    b .
    b .
      
reset:
    ldr r0, =CM_ICLKEN_PER
    ldr r1, =(1 << 16)
    str r1, [r0]
 
    ldr r0, =GPIO5_OE
    ldr r1, =0
    str r1, [r0]
 
    ldr r0, =GPIO5_DATAOUT
    ldr r1, =(1 << 21)
    str r1, [r0]
 
    ldr r2, =0x00000000
0:
    eor r2, r1
    str r2, [r0]
    ldr r3, =100000000
1:
    subs r3, #1
    bne 1b
    b 0b
    .end

main.ld

MEMORY
{
  RAM : ORIGIN = 0, LENGTH = 32M
}

SECTIONS
{
  .text : { *(.text*) } > RAM
  .data : { *(.data*) } > RAM
}

Makefile

all:
	arm-linux-gnueabihf-as -mcpu=cortex-a7 -o main.o main.s
	arm-linux-gnueabihf-ld -T main.ld -o main.elf main.o
	arm-linux-gnueabihf-objcopy -O binary main.elf u-boot.img

clean:
	rm -rf u-boot.img main.o main.elf

編譯

$ make
    arm-linux-gnueabihf-as -mcpu=cortex-a7 -o main.o main.s
    arm-linux-gnueabihf-ld -T main.ld -o main.elf main.o
    arm-linux-gnueabihf-objcopy -O binary main.elf u-boot.img

複製u-boot.img到MicroSD根目錄，接著開啟電源即可