掌機 - TRIMUI - Assembly - LED

參考資料：
http://nano.lichee.pro/
https://mangopi.org/mangopi_r

暫存器


紅色LED是接到PE5


輸出控制


main.s

    .global _start
   
    .equiv GPIO_BASE, 0x01c20800 
    .equiv PE,        (4 * 0x24)
    .equiv PORT_CFG0, 0x00
    .equiv PORT_DATA, 0x10
    
    .arm
    .text
_start:
    .long 0xea000016
    .byte 'e', 'G', 'O', 'N', '.', 'B', 'T', '0'
    .long 0, __spl_size
    .byte 'S', 'P', 'L', 2
    .long 0, 0
    .long 0, 0, 0, 0, 0, 0, 0, 0
    .long 0, 0, 0, 0, 0, 0, 0, 0
    
_vector:
    b reset
    b .
    b .
    b .
    b .
    b .
    b .
    b .
    
reset:
    ldr r0, =GPIO_BASE
    ldr r1, =0x100000
    str r1, [r0, #(PE + PORT_CFG0)]
  
0:
    ldr r1, =0x20
    str r1, [r0, #(PE + PORT_DATA)]
    ldr r2, =500000
1:
    subs r2, #1
    bne 1b
    ldr r1, =0x00
    str r1, [r0, #(PE + PORT_DATA)]
    ldr r2, =500000
2:
    subs r2, #1
    bne 2b
    b 0b
    .end

P.S. 紅色LED陰極連接到PE5，陽極則是連接到USB C，因此，必須插上USB C才可以測試

main.ld

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

MEMORY {
    ram : ORIGIN = 0x00000000, LENGTH = 32M
}

SECTIONS {
    .text :
    {
        PROVIDE(__spl_start = .);
        *(.text*)
        PROVIDE(__spl_end = .);
        *(.init.text)
        *(.exit.text)
        *(.glue*)
        *(.note.gnu.build-id)
    } > ram
    PROVIDE(__spl_size = __spl_end - __spl_start);

    .rodata ALIGN(8) :
    {
        PROVIDE(__rodata_start = .);
        *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
        PROVIDE(__rodata_end = .);
    } > ram

    .data ALIGN(8) :
    {
        PROVIDE(__data_start = .);  
        *(.data*)
        . = ALIGN(8);
            PROVIDE(__data_end = .);
        PROVIDE(__image_end = .);
    } > ram

    .bss ALIGN(8) (NOLOAD) :
    {
        PROVIDE(__bss_start = .);
        *(.bss*)
        *(.sbss*)
        *(COMMON)
        . = ALIGN(8);
        PROVIDE(__bss_end = .);
    } > ram

    .stab 0 : { *(.stab) }
    .stabstr 0 : { *(.stabstr) }
    .stab.excl 0 : { *(.stab.excl) }
    .stab.exclstr 0 : { *(.stab.exclstr) }
    .stab.index 0 : { *(.stab.index) }
    .stab.indexstr 0 : { *(.stab.indexstr) }
    .comment 0 : { *(.comment) }
    .debug_abbrev 0 : { *(.debug_abbrev) }
    .debug_info 0 : { *(.debug_info) }
    .debug_line 0 : { *(.debug_line) }
    .debug_pubnames 0 : { *(.debug_pubnames) }
    .debug_aranges 0 : { *(.debug_aranges) }
}

Makefile

all:
	arm-none-eabi-as -mcpu=arm9 -o main.o main.s
	arm-none-eabi-ld -T main.ld -o main.elf main.o
	arm-none-eabi-objcopy -O binary main.elf main.bin
	gcc mksunxi.c -o mksunxi
	./mksunxi main.bin

run:
	sunxi-fel -p write 0 main.bin && sunxi-fel exec 0

clean:
	rm -rf main.bin main.o main.elf

進入燒錄模式後，然後插入USB至電腦，可以找到如下裝置

$ lsusb
    Bus 002 Device 081: ID 1f3a:efe8 Onda (unverified) V972 tablet in flashing mode

編譯、執行

$ make
    arm-none-eabi-as -mcpu=arm9 -o main.o main.s
    arm-none-eabi-ld -T main.ld -o main.elf main.o
    arm-none-eabi-objcopy -O binary main.elf main.bin
    gcc mksunxi.c -o mksunxi
    ./mksunxi main.bin
    The bootloader head has been fixed, spl size is 512 bytes.

$ make run
    sunxi-fel -p write 0 main.bin && sunxi-fel exec 0
    100% [================================================]     1 kB,  146.0 kB/s

完成