微處理器 - Raspberry Pi RP2040 (Pico) - Assembly - LED

參考資訊：
https://github.com/carlosftm/RPi-Pico-Baremetal
https://www.digikey.com/en/maker/projects/raspberry-pi-pico-and-rp2040-cc-part-1-blink-and-vs-code/7102fb8bca95452e9df6150f39ae8422

LED腳位


IO_BANK0


GPIO25_CTRL


SIO_BASE


GPIO_OE、GPIO_OUT_XOR


main.s

    .equiv IO_BANK0_BASE,   0x40014000
    .equiv ATOMIC_BASE,     0x4000f000
    .equiv SIO_BASE,        0xd0000000
    .equiv GPIO25_CTRL,     0xcc
    .equiv SIO,             5
    .equiv GPIO_OE,         0x20
    .equiv GPIO_OUT_XOR,    0x1c
    .equiv IO_BANK0,        32

    .thumb
    .global _start
_start:
    ldr r0, =ATOMIC_BASE
	ldr r1, =IO_BANK0
	str r1, [r0]

    ldr r0, =IO_BANK0_BASE + GPIO25_CTRL
    ldr r1, =SIO
    str r1, [r0]

    ldr r0, =SIO_BASE
    ldr r1, =(1 << 25)
    str r1, [r0, #GPIO_OE]

0:
    str r1, [r0, #GPIO_OUT_XOR]
    ldr r2, =100000
1:
    sub r2, r2, #1
    cmp r2, #0
    bne 1b
    b 0b
    .end

main.ls

MEMORY {
    RAM : ORIGIN = 0x20040000, LENGTH = 32K
}

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

Makefile

all:
	arm-none-eabi-as -mcpu=cortex-m0plus main.s -o main.o
	arm-none-eabi-ld -nostdlib --entry 0x20040001 -T main.ld main.o -o main.elf
	arm-none-eabi-objcopy -O binary main.elf main.bin
	/opt/picotool/build/picotool uf2 convert main.elf main.uf2

clean: 
	rm -f *.bin *.o *.elf *.list *.uf2

編譯

$ make
    arm-none-eabi-as -mcpu=cortex-m0plus main.s -o main.o
    arm-none-eabi-ld -nostdlib --entry 0x20040001 -T main.ld main.o -o main.elf
    arm-none-eabi-objcopy -O binary main.elf main.bin
    /opt/picotool/build/picotool uf2 convert main.elf main.uf2

按住BOOTSEL按鈕後，插入到PC，接著將main.uf2拖進隨身碟即可