include "reg196mc.asm"
cseg at 30h
temp: dsb 1
org 203ch ;中断向量
dcw EXTINT
org 2080h
ljmp Start
Start:
ldb temp,#00h
ld ax,#0000h
st ax,p2_mode[0]
ldb al,#00h
stb al,p2_dir[0]
ldb al,#00000101b ;下降沿触发
stb al,WG_PROTECT
ldb INT_MASK1, #01000000b ; enable extint
ei
Loop:
nop
ljmp Loop
EXTINT:
pushf
di
call p2_io
ei
popf
ret
p2_io: inc temp
nop
stb temp,p2_reg[0]
stb temp,p2_pin[0]
ret
end