Question

我正在为ATmega16编写这个组件，我只是想按下按钮使LED闪烁10次。不幸的是，当到达RET指令时，它会将我带到第一个代码（开始），而不是返回到调用LONG_DELAY时它离开的位置。

有人可以帮帮我吗？感谢。

start:
    /* set the PINB0 data direction to 0 for input */
    /* This one simulates the key */
    ldi R16, (0 << PB0) ; Load 0b00000001 in R16
    out DDRB,R16    ; Configure the PINB0 as input

    /* set the PORTB7 data direction to 1 for output */
    /* this one causes the LED to be ON/OFF */
    ldi R17, (1 << PB7) ; Load 0b10000000 in R17
    out DDRB,R17    ; Configure the PORTB7 as output

OFF_MODE:
    /* Put the PORTB7 to 0 */ 
    ldi R18,(0 << PB7)
    out PORTB,R18
    /* Check the content of PINB0 */
    /* Wait for the PINB to get pressed by the user */
    sbis PINB,0
    brne OFF_MODE   ; Branch to the OFF_MODE if the key isn't pressed yet

BLINK_MODE:
    /* Define a counter */
    ldi R20,0
    /* Turn on the LED */
    /* Put the PORTB7 to 1 */
    ldi R18,(1 << PB7)
    out PORTB,R18

    /* Create a delay */
    call LONG_DELAY

    /* Turn off the LED */
    ldi R18,(0 << PB7)
    out PORTB,R18

    /* Increment the counter */
    inc R20

    /* Check the content of the counter */
    cpi R20,0x0A
    brne BLINK_MODE
    /* Clear the input to avoid duplicate press virtualization */
    cbi PINB,0
    jmp OFF_MODE
rjmp start

    /* Delay function */
LONG_DELAY:
    ldi r25,10
LOOP:
    nop
    dec R25
    cpi R25,0
    brne LOOP
    ret

Answer 1

有一些错误，所以你在这里：

; Replace with your application code
start:
    //stack setup
    ldi r16, 0
    out SPH, r16
    ldi r16, 0xf0
    out SPL, r16
    /* set the PINB0 data direction to 0 for input */
    /* This one simulates the key */
    ldi R16, (0 << PB0) ; Load 0b00000001 in R16
    out DDRB,R16    ; Configure the PINB0 as input

    /* set the PORTB7 data direction to 1 for output */
    /* this one causes the LED to be ON/OFF */
    ldi R17, (1 << PB7) ; Load 0b10000000 in R17
    out DDRB,R17    ; Configure the PORTB7 as output

OFF_MODE:
    /* Put the PORTB7 to 0 */ 
    ldi R18,(0 << PB7)
    out PORTB,R18
    /* Check the content of PINB0 */
    /* Wait for the PINB to get pressed by the user */
    sbis PINB,0
    brne OFF_MODE   ; Branch to the OFF_MODE if the key isn't pressed yet
//Here was mistake
    ldi R20, 10

BLINK_MODE:
    /* Turn on the LED */
    /* Put the PORTB7 to 1 */
    ldi R18,(1 << PB7)
    out PORTB,R18

    /* Create a delay */
    call LONG_DELAY

    /* Turn off the LED */
    ldi R18,(0 << PB7)
    out PORTB,R18

    /* Increment the counter */
    dec R20
    brne BLINK_MODE
    /* Clear the input to avoid duplicate press virtualization */
    cbi PINB,0
    jmp OFF_MODE
rjmp start

    /* Delay function */
LONG_DELAY:
    ldi r25,10
LOOP:
    dec R25
//here was redundant instruction 
    brne LOOP
    ret

RET指令没有返回到它所谓的子程序 - AVR汇编

1 个答案: