Assembly 使用按钮在组件中设置AVR LED开关程序

我正在使用ATMELStudio7为ATMEL ATmega16编写汇编代码。 我只想在按下一个按钮时打开一个LED，我想在再次按下时将其关闭。就像房间里的灯一样。出于某种原因，此代码只打开灯，按下按钮时从不熄灭（按钮在proteus中模拟）。有人能帮我写这个简单的代码吗

start:
    /* set the PIND2 data direction to 0 for input */
    /* This one simulates the key */
    ldi R16, (0 << PD2) ; Make PD2 as input
    out DDRB,R16    ; Configure the PIND2 as input

    /* set the PORTB7 data direction to 1 for output */
    /* this one causes the LED to be ON/OFF */
    ldi R17, (1 << PB7) ; Make PB7 as output 
    out DDRB,R17    ; Configure the PORTB7 as output

OFF_MODE:
    /* Put the PORTB7 to 0 */ 
    ldi R18,(0 << PB7)
    out PORTB,R18
    call delay
    /* Skip if PIN 2 in PORT D is set */
    sbis PIND,2
    jmp OFF_MODE    ; Branch to the OFF_MODE if the key isn't pressed yet

ON_MODE:
    /* Put the PORTB to 1 */
    ldi R18,(1 << PB7)
    out PORTB,R18
    call delay
    /* Skip if PIN 2 in PORT D is set */
    sbis PIND,2
    jmp ON_MODE ; Branch to the ON_MODE if the key isn't unpressed yet
rjmp start
delay:
    ldi r16, 0xFF
delay_loop_1:
    dec r16
    cpi r16, 0x00
    jmp delay_loop_1
ret

开始：
/*输入时，将PIND2数据方向设置为0*/
/*这个模拟钥匙*/
ldi R16，（0您的
延迟功能中有一个无限循环。请注意使用：

delay:
    ldi r16, 0xFF
delay_loop_1:
    dec r16
    brne delay_loop_1
    ret