Quizzing system with buzzer:
org 00h
as equ p2.0
bs equ p2.1
cs equ p2.2
dsp equ p2.3
seg equ p0
setb p1.0
setb p1.1
setb p1.2
setb p1.3
clr p3.0
clr a
mov p2,a
check: clr p3.0
jnb p1.0,l1
jnb p1.1,l2
jnb p1.2,l3
jnb p1.3,l4
sjmp check
l1: setb as
clr bs
clr cs
clr dsp
setb p3.0
mov seg,#0f9h
acall delay
sjmp check
l2: clr as
setb bs
clr cs
clr dsp
setb p3.0
mov seg,#24h
acall delay
sjmp check
l3: clr as
clr bs
setb cs
clr dsp
setb p3.0
mov seg,#30h
acall delay
sjmp check
l4: clr as
clr bs
clr cs
setb dsp
setb p3.0
mov seg,#19h
acall delay
sjmp check
delay: mov r0,#0ffh
here1: mov r1,#0ffh
here: djnz r1,here
djnz r2,here1
ret
