VTech Alphabert s Magic Readport User Manual download pdf (Page 30)

Lab Manual of Microcontroller & Interfacing Page 30

ajmp flash

sequence:

mov a,#0FEh ; Bit pattern for First LED ON, others OFF

next: mov P1,a ; Transfer bit pattern to port P1

rl a ; Rotate for next LED

acall delay ; Delay

ajmp next ; Repeat loop

delay: mov R4,#02h

loop3: mov R6,#0ffh

loop2: mov R5,#0ffh

loop1: djnz R5,loop1

djnz R6,loop2

djnz r4,loop3

ret

end

:: WORKSHEET ::

Exercise: Modify program such that when INT0 occurs, LEDs flash ten times and then stop.

When INT1 occurs LEDs glows one by one sequentially only once and then stop.

Hint: Use separate register as a counter.

Memory

Location

HEX

code

Label Opcode Operands Comments

1 2 ... 25 26 27 28 29 30 31 32 33 34 35 ... 79 80

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VTech Alphabert s Magic Readport User Manual Page 30