微處理器 - Microchip ATSAMD21G18 (Seeed Studio XIAO SAMD21) - Assembly - Button

參考資訊：
https://github.com/dwelch67/atsamd_samples
https://cdn.sparkfun.com/datasheets/Dev/Arduino/Boards/Atmel-42181-SAM-D21_Datasheet.pdf

按鍵腳位(PA-6)


暫存器



配置方式


main.s

    .cpu cortex-m0
    .thumb

    .equiv PORT_BASE,    0x41004400
    .equiv PORT_A,       0x00
    .equiv PORT_DIR,     0x00
    .equiv PORT_OUT,     0x10
    .equiv PORT_IN,      0x20
    .equiv PORT_PINCFG6, 0x46

    .thumb_func
    .global _start
_start:
    .word 0x20001000
    .word reset
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
    .word hang
 
    .thumb_func
reset:
    ldr r0, =PORT_BASE
    ldr r1, =(1 << 17)
    str r1, [r0, #(PORT_A + PORT_DIR)]
    ldr r1, =0xffffffff
    str r1, [r0, #(PORT_A + PORT_OUT)]
    ldr r1, =(1 << 2) | (1 << 1)
    ldr r2, =PORT_BASE + PORT_A + PORT_PINCFG6
    strb r1, [r2]

0:
    ldr r1, [r0, #(PORT_A + PORT_IN)]
    lsl r1, #11
    ldr r2, =(1 << 6)
    orr r1, r2
    str r1, [r0, #(PORT_A + PORT_OUT)]
    b 0b
 
    .thumb_func
hang:
    b .
    .end

完成