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部分源程序：keydata equ 30h
org 00h
main:
mov keydata,#0
mov tmod ,#09h
mov r7,#0
mov r6,#0
jb p3.2,$
again:
mov tl0,#0
mov th0,#0
setb tr0
jnb p3.2,$
jb p3.2,$
clr tr0
mov a,th0
clr c
subb a,#12
jc again
mov a,#14
clr c
subb a,th0
jc again ;seaching start bit: 3.6ms
nextbit:
mov tl0,#0
mov th0,#0
setb tr0
jnb p3.2,$
jb p3.2,$
clr tr0
mov a,th0
clr c
subb a,#8
jc next ;;;;;;;;;;if <2.2ms
mov a,#10
clr c
subb a,th0
jc again ;;;;;;;if >2.7ms
mov a,keydata
setb c ;bit = 1
rrc a
mov keydata,a
inc r7
cjne r7,#8,nextbit
inc r6
cjne r6,#2,last8
sjmp seach
last8:
mov keydata+1,a
mov r7,#0
sjmp nextbit
next:
mov a,th0
swap a
mov r1,a
anl tl0,#0f0h
mov a,tl0
clr c
rrc a
rrc a
rrc a
rrc a
add a,r1
mov r1,a
subb a,#30
jc nextbit ; if <0.84ms
mov a,r1
clr c
cjne a,#64,continue
continue:
jnc nextbit ; if >1.11ms
mov a,keydata
clr c ;bit = 0
rrc a
mov keydata,a
inc r7
cjne r7,#8,nextbit
inc r6
cjne r6,#2,last_8
sjmp seach
last_8:
mov keydata+1,a
mov r7,#0
sjmp nextbit
seach:
mov r0,#-2 ;pointer
mov r1,#-1 ;counter
seach1:
inc r0
seach2: inc r0
inc r1
cjne r1,#29,compare
sjmp exit0
compare:
mov a,r0
mov dptr,#keycode
movc a,@a+dptr
cjne a,keydata,seach1
inc r0
mov a,r0
mov dptr,#keycode
movc a,@a+dptr
cjne a,keydata+1,seach2
mov p1,r1 ;output to p1
send:
mov tmod,#20h ; timer 1,mode 2
mov tl1,#0fdh
mov th1,#0fdh
mov scon,#01010000b;9600,8,1,0
setb tr1
loop_s:
mov sbuf,r1 ;send to the serial port of computer
jnb ti,$
clr ti
exit0:
ljmp main
keycode:
db 11111000b,00000000b, 11111100b,00000000b, 11111001b,11000000b
db 11111100b,11000000b, 11111010b,00000000b, 11111010b,00100000b
db 11111010b,01000000b, 11111010b,01100000b, 11111010b,10000000b
db 11111010b,10100000b, 11111010b,11000000b, 11111010b,11100000b
db 11111011b,00000000b, 11111011b,00100000b, 11111011b,01000000b
db 11111011b,01100000b, 11111111b,01100000b, 11111111b,10100000b
db 10001100b,10001110b, 10001101b,11101110b, 10001100b,10101110b
db 10001101b,11001110b, 11111000b,11100000b, 11111100b,10000000b
db 11111100b,01000000b, 11111001b,10100000b, 11111100b,10100000b
db 11111100b,01100000b
end
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