LPC812 >> Assembly

LED

---

參考資訊：
1. pdf
2. LPC810-ASM

Register


main.S

.cpu cortex-m0
.thumb

.equ GPIO_DIR0, 0xa0002000
.equ GPIO_PIN0, 0xa0002100
.equ GPIO_SET0, 0xa0002200
.equ GPIO_CLR0, 0xa0002280

.equ BIT1,  1
.equ BIT7,  7
.equ BIT16, 16
.equ BIT17, 17

.thumb_func
.global _start
_start:
.word 0x10000400 @ stacktop
.word reset @ reset
.word hang @ nmi
.word hang @ hardfault
.word hang @ reserved
.word hang @ reserved
.word hang @ reserved
.word hang @ reserved
.word hang @ reserved
.word hang @ reserved
.word hang @ reserved
.word hang @ svcall
.word hang @ reserved
.word hang @ reserved
.word hang @ pendsv
.word hang @ systick

.thumb_func
reset:
  ldr r0, =GPIO_DIR0
  ldr r1, =((1 << BIT7) | (1 << BIT16) | (1 << BIT17))
  str r1, [r0]

loop:
  ldr r0, =GPIO_SET0
  ldr r1, =((1 << BIT7) | (1 << BIT16) | (1 << BIT17))
  str r1, [r0]
  bl delay

  ldr r0, =GPIO_CLR0
  ldr r1, =((1 << BIT7) | (1 << BIT16) | (1 << BIT17))
  str r1, [r0]
  bl delay
  b loop

delay:
  push {lr}
  ldr r0, =3000000
1:
  nop
  sub r0, #1
  bne 1b
  pop {pc}

hang:
  b .
.end

main.ld

OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
OUTPUT_ARCH(arm)

MEMORY
{
  rom (rx) : ORIGIN = 0x00000000, LENGTH = 0x00001000
  ram (rwx) : ORIGIN = 0x10000000, LENGTH = 0x00000400
}

SECTIONS
{
  . = 0x0;
  .text : { *(.text*) } > rom
  .rodata : { *(.rodata*) } > rom
  .bss : { *(.bss*) } > ram
  . = ALIGN(8);
}

編譯

$ arm-none-eabi-as -mcpu=cortex-m0 -mthumb main.S -o main.o
$ arm-none-eabi-ld -o main.elf -T main.ld main.o
$ arm-none-eabi-objcopy main.elf main.bin -O binary
$ arm-none-eabi-objcopy main.elf main.hex -O ihex

燒錄步驟：
1. 連接USB與PC
2. P0_12接到GND
3. 按一下RST按鍵
4. 鬆開P0_12
5. 執行如下命令

$ sudo lpc21isp -wipe -control -verify -debug2 ./main.hex /dev/ttyUSB0 9600 12000

完成

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