PROGRAM TO CHECK THE KEY BOARD.

org 0000h
mov psw,#00h
mov dptr,#0400h
mov r7,#00h
mov b,#00h

x7: mov a,r7
movc a,@a+dptr
mov p0,a

mov r0,#08h
mov a,b
setb c
x1: rlc a
mov p2,a
djnz r0,x1

acall kb
ajmp x7

kb: mov a,p1
jnb acc.0,z1
jnb acc.1,z2
jnb acc.2,z3
jnb acc.3,z4
jnb acc.4,z5
ret

z1: mov r7,#01h
ret
z2: mov r7,#02h
ret
z3: mov r7,#03h
ret
z4: mov r7,#04h
ret
z5: mov r7,#05h
ret

org 0400h

db 77h
db 44h
db 3dh
db 7ch
db 4eh
db 7ah
db 7bh
db 54h
db 7fh
db 7eh

end