微處理器 - NXP LPC812 - Assembly - LED

參考資訊：
https://github.com/BakaOsaka/LPC810-ASM
https://studio.segger.com/packages/LPC800/CMSIS/Documents/UM10601.pdf

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