《微机原理与接口技术》课程设计Word格式.docx
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8253的主要工作原理是：
8253其本质为减一计数器，其工作过程为：
首先需要设置工作方式，然后将工作方式处置置入计数初值锁存器；
启动计数后，CPU向8253的计数初值锁存器赋初值，每来一个CLK信号，减一计数器减1，直到减到0或
1时，就发出输出信号OUT输出
74LS393
（1）74LS393为一个双4位二进制计数器，主要用于二进制计数。
（2）
1CP
VCC
1RD
2CP
1QA
2RD
1QB
2QA
1QC
2QB
1QD
2QC
GND
2QD
4.工作原理示意图
⑴8253的CLK1接分频输出端1MHz。
⑵GATE1接PB0。
⑶OUT1接VIN（音频功放单元JP→＋5V（ON））。
⑷CS3→0040H。
⑸JX8→JX0。
（6）IORD→IORDIOWR→IOWR
（7）A0→A0A1→A1
（8）按1、2……7键，依次发出1、2……7音调声。
5.程序设计流程图
6.程序代码
CODE
SEGMENT
ASSUMECS:
CODE,DS:
CODE
CONTROL
equ43h
COUNT0
equ40h
COUNT1
equ41h
COUNT2
equ42h；
以上是定义8253地址端口
IOCONPT
EQU0FF2BH
IOBPT
EQU0FF29H
IOAPT
EQU0FF28H；
以上定义8255端口地址
PA
EQU0FF21H;
字位口
PB
EQU0FF22H;
字形口
PC
EQU0FF23H;
键入口；
以上定义8155端口地址
ORG1000H
START:
JMPSTART0
BUF
DB
KZ
ltime
db
lkey
db
ZP
DW
data1:
db0c0h,0f9h,0a4h,0b0h,99h,92h,82h,0f8h,80h,90h,88h,83h,0c6h,0a1h
db86h,8eh,0ffh,0ch,89h,0deh,0c7h,8ch,0f3h,0bfh,8FH,0F1H
data3:
dw2273,2024,1805,1704
dw1517,1353,1205,1136
START0:
movax,cs
movds,ax
CALLBUF1
MOVAL,88H
MOVDX,IOCONPT
OUTDX,AL
movdx,IOBPT
moval,00
outdx,al
movzp,offsetbuf
redikey:
calldispkey
cmpKZ,09h
JNCredikey
cmpkz,01h
jcredikey
movbx,zp
moval,kz
mov[bx],al
cmpbx,offsetbuf+5
jzzp1
incbx
movzp,bx
jmpouttone
zp1:
outtone:
moval,0ffh
movah,00h
decax
shlax,1
movbx,offsetdata3
addbx,ax
movax,[bx]
callt8253
movcx,20h
con1:
pushcx
calldisp
popcx
loopcon1
jmpredikey
t8253:
pushax
moval,76h;
计数器1,16位二进制,方式3。
movdx,CONTROL
outdx,al
popax
movdx,COUNT1
moval,ah
ret
;
-------------------------
dispkey:
callkey
movah,al;
newkey
movbl,ltime;
ltime
movbh,lkey;
lkey
moval,01h
movdx,0ff21h
cmpah,bh
movbh,ah;
bh=newkey
movah,bl;
al=time
jzdisk4
movbl,88h
movah,88h
disk4:
decah
cmpah,82h
jzdisk6
cmpah,0eh
cmpah,00h
jzdisk5
movah,20h
decbl
jmpdisk7
disk5:
movah,0fh
disk6:
movbl,ah
movah,bh
disk7:
movltime,bl
movlkey,bh
movKZ,bh
moval,ah
key:
movdx,0ff22h
movbl,00h
movah,0feh
movcx,08h
key1:
rolal,01h
movah,al
nop
movdx,0ff23h
inal,dx
notal
andal,0fh
jnzkey2
incbl
loopkey1
jmpnkeY
key2:
testal,01h
jekey3
moval,00h
jmpkey6
key3:
testal,02h
jekey4
moval,08h
key4:
testal,04h
jekey5
moval,10h
key5:
testal,08h
jenkey
moval,18h
key6:
addal,bl
cmpal,10h
jncfkey
movbl,al
movbh,0h
movsi,offsetdata2
moval,[bx+si]
nkey:
moval,20h
fkey:
data2:
db07h,04h,08h,05h,09h,06h,0ah,0bh
DB01h,00h,02h,0fh,03h,0eh,0ch,0dh
DISP:
MOVAL,0FFH;
00H
MOVDX,PA
MOVCL,0DFH;
20H;
显示子程序,5ms
MOVBX,OFFSETBUF
DIS1:
MOVAL,[BX]
MOVAH,00H
PUSHBX
MOVBX,OFFSETDATA1
ADDBX,AX
POPBX
MOVDX,PB
MOVAL,CL
PUSHCX
DIS2:
MOVCX,0a0H
LOOP$
POPCX
CMPCL,0FEH
JZLX1
INCBX
RORCL,1
JMPDIS1
LX1:
MOVAL,0FFH
RET
BUF1:
MOVBUF,11H
MOVBUF+1,10H
MOVBUF+2,10H
MOVBUF+3,10H
MOVBUF+4,10H
MOVBUF+5,10H
ENDS
ENDSTART
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