微處理器 - Microchip ATtiny13 - Assembly - Self-Programming the Flash

參考資訊：
https://www.microchip.com/en-us/product/attiny13#Documentation
https://www.avrfreaks.net/forum/self-programming-tiny13-solved
https://nerdathome.blogspot.com/2008/04/avr-as-usage-tutorial.html

Program Flash的操作都是以Page為單位，一個Page是16 Words(32 Bytes)，Z(r32:r30)暫存器是位址，r1:r0則是Word的資料，唯一要注意的地方是，填寫的位址是0x00開始


main.s

    .equ SPMCSR,  0x37
  
    .org 0x0000
    rjmp main
  
    .org 0x0020
main:
    rcall program_flash
  
loop:
    rjmp loop
 
program_flash:
    ; erase
    ldi r30, 0x00
    ldi r31, 0x01
    ldi r16, 0x03
    out SPMCSR, r16
    spm

    ; fill (0x100: 0x50, 0xa0, 0x5a, 0xa1...)
    ldi r30, 0x00
    ldi r31, 0x00
    ldi r18, 0x50
    ldi r19, 0xa0
    ldi r17, 16
0:
    mov r0, r18
    mov r1, r19
    ldi r16, 0x01
    out SPMCSR, r16
    spm
    inc r18
    inc r19
    inc r30
    inc r30
    dec r17
    tst r17
    brne 0b

    ; write
    ldi r30, 0x00
    ldi r31, 0x01
    ldi r16, 0x05
    out SPMCSR, r16
    spm
    ret

編譯和燒錄

$ avr-as -mmcu=attiny13 -o main.o main.s
$ avr-ld -o main.elf main.o
$ avr-objcopy --output-target=ihex main.elf main.ihex
$ sudo avrdude -c usbasp -p t13 -B 1024 -U flash:w:main.ihex:i

接著讀取Flash

$ sudo avrdude -c usbasp -p t13 -B 1024 -U flash:r:flash.bin:r

完成