blink led

[vead]

I want to blink led for some time
I made diagram using proteus
component
AT89C51
crystal
LED

diagram

assembly code

       org 00h
    
      Setb P1.0          ; Led on
      clr   P1.0           ; Led off
     
       delay:
    mov    R1, #20
    mov    R2, #0
delay1:    djnz    R2, delay1
    djnz    R1, delay1
  
   ret
   end

Q but Led is not blinking ?

 

[KrisBlueNZ]

Hardware errors:

1. C3 should be higher than 1 nF. I suggest 100 nF.
2. Add a pulldown resistor of around 10k from pin 9 to 0V.
3. R2 must connect to VCC, not 0V.
4. R2 must be a lot lower than 500k. For example try 470Ω.

Firmware errors:

1. You need to insert delays between the instructions that change the LED state.
2. You need to make the LED state logic into a continuous loop, using a label at the start and an RJMP at the end.

        ORG     0

MainLoop:
        setb    P1.0                    ; Turn LED ON
        rcall   Delay                   ; Wait a short time
        clr     P1.0                    ; Turn LED OFF
        rcall   Delay                   ; Wait a short time
        rjmp    MainLoop                ; Loop forever

Delay:
        mov     R1,#20                  ; Set up outer loop count
        mov     R2,#0                   ; Set up inner loop count
Delay1: djnz    R2,Delay1               ; Inner loop
        djnz    R1,Delay1               ; Outer loop
        ret

        end

 

[vead]

you mean this type

 

[KrisBlueNZ]

You've removed the pushbutton, and C3, and the connection to pin 31. Put those all back like in your diagram in post #1. You don't need R1 though. Actually I think R1 was supposed to be connected to pin 9 but you connected it to pin 31 instead.

 

[vead]

now the led is blinking for very short time

thank you very much for your help

 

[KrisBlueNZ]

Your schematic is still wrong. Here's exactly how it should look.