附录：实验代码：（完整的源程序）
CODE SEGMENT ASSUME
CS:CODE,DS:CODE,ES:CODE ORG 3400H Start: JMP program
LedMap: 八段管显示码
db 0c0h,0f9h,0a4h,0b0h,099h,092h,082h,0f8h db
080h,090h,088h,083h,0c6h,0a1h,086h,08eh ;db 0bfh db 0f7h
KeyTable: ;键码定义
db 07h,04h,08h,05h,09h,06h,0ah,0bh db 01h,00h,02h,0fh,03h,0eh,0ch,0dh
OUTSEG equ 0ffdch ;段控制口
OUTBIT equ 0ffddh ;位控制口/键扫口 IN_KEY equ 0ffdeh ;键盘读入口 LedBuf db 6 dup(?) ;显示缓冲 time DB 0,0,0,0,0,0 ;INTNum equ 20
Port_8259_0 EQU 0FFE0H ;1110_0000 Port_8259_1 EQU 0FFE1H
Port_8253_00 EQU 0FFE4H ; 0_01 Port_8253_01 EQU 0FFE5H Port_8253_10 EQU 0FFE6H Port_8253_11 EQU 0FFE7H
program:
call initCLK0 CLI
MOV AX,OFFSET int8259 MOV BX,003CH MOV [BX],AX MOV BX,003EH MOV AX,0000H MOV [BX],AX
STI
call init8259
call update_ledbuff mainLoop: call display call handle_key jmp mainLoop
;================================ initCLK0: mov dx,Port_8253_11 mov al,00110100b out dx,al mov dx,Port_8253_00 ;clk0 mov ax,38400 out dx,al mov al,ah out dx,al ret
;================================init8259:
MOV AL,13H
MOV DX,Port_8259_0 OUT DX,AL MOV AL,08H
MOV DX,Port_8259_1 OUT DX,AL MOV AL,09H OUT DX,AL
MOV AL,7FH ;IRQ7 OUT DX,AL RET
;================================int8259: cli
push ax push bx push cx
MOV AL,20H 0010 MOV DX,Port_8259_0 OUT DX,AL
call timeInc
call update_ledbuff pop cx pop bx pop ax sti iret
;========================================= timeInc:
push bx push cx
mov bx,offset time
add bx,5 ;取time[5] inc byte ptr [bx] cmp byte ptr [bx],10 jb next5
mov byte ptr [bx],0 ;该位清零 dec bx ;下一位加1 inc byte ptr [bx] inc bx next5: dec bx
cmp byte ptr [bx],6 jb next4
mov byte ptr [bx],0 dec bx
inc byte ptr [bx] inc bx
next4: dec bx
cmp byte ptr [bx],10 jb next3
mov byte ptr [bx],0 dec bx
inc byte ptr [bx] inc bx
next3: dec bx cmp byte ptr [bx],6 jb next2
mov byte ptr [bx],0 dec bx
inc byte ptr [bx] inc bx
next2: dec bx dec bx
cmp byte ptr [bx],2 jnz cmp10
cmp4: inc bx
cmp byte ptr [bx],4 jb next1 mov byte ptr [bx],0 dec bx
mov byte ptr [bx],0 jmp over_timeInc
cmp10: inc bx
cmp byte ptr [bx],10 jb next1
mov byte ptr [bx],0 dec bx
inc byte ptr [bx] inc bx
next1: dec bx
cmp byte ptr [bx],3 jb over_timeInc mov byte ptr [bx],0
over_timeInc: pop cx pop bx ret
;================================ display:
push ax push bx
push cx push dx
mov bx,offset LEDBuf
mov cl,6 ;共6个八段管 ;从左边开始显示
mov ah,00100000b
DLoop:
mov dx,OUTBIT mov al,0
out dx,al ;关所有八段管
mov al,[bx]
mov dx,OUTSEG out dx,al
mov dx,OUTBIT mov al,ah
out dx,al ;显示一位八段管
push ax mov ah,1 call Delay pop ax
shr ah,1 inc bx dec cl jnz DLoop
mov dx,OUTBIT mov al,0
out dx,al ;关所有八段管 pop dx pop cx pop bx pop ax ret
;================================ update_ledbuff: push ax push bx push cx push dx mov cl,6
uloop: mov bx,offset time mov al,cl dec al mov ah,0
xlat ;取出time[cl-1]
mov bx,offset LEDMAP mov ah,0
xlat ;查找对应字形码
mov bx,offset LedBuf mov ch,0 add bx,cx dec bx
mov [bx],al ;放入LedBuf[cl-1]
dec cl jnz uloop pop dx pop cx pop bx pop ax ret
;================================ Delay: ;延时子程序 push cx
mov cx,256 loop $ pop cx ret
Delay1: 延时子程序 push cx mov cx,50 lxxx:
call display loop lxxx pop cx ret
;================================ handle_key:
call read_key
cmp al,0ch jne nextR jmp nextC nextR:
ret nextC:
cli
mov bx, offset time
mov cl,6 loop_d:
mov byte ptr [bx],16 inc bx loop loop_d
call update_ledbuff mov bx, offset time t1: call Display call read_key cmp al,2 ja t1 t1_over: mov [bx],al
call update_ledbuff call Delay1 t2: call Display call read_key CMP AL,0DH JNE T22 mov byte ptr [bx],16 call update_ledbuff call Delay1 JMP T1 T22:
cmp al,9 ja t2
cmp byte ptr [bx],2 je cmp_k_4 jmp t2_over
cmp_k_4:cmp al,3 ja t2
jmp t2_over t2_over:
inc bx
mov [bx],al
call update_ledbuff call Delay1 t3: call Display call read_key CMP AL,0DH JNE T33 mov byte ptr [bx],16 DEC BX call update_ledbuff call Delay1 JMP T2 T33:
cmp al,5 ja t3
t3_over:
inc bx
mov byte ptr[bx],al call update_ledbuff call Delay1 t4: call Display call read_key CMP AL,0DH JNE T44 mov byte ptr [bx],16 DEC BX call update_ledbuff call Delay1 JMP T3 T44:
cmp al,9 ja t4
t4_over:
inc bx
mov [bx],al
call update_ledbuff call Delay1 t5: call Display call read_key
;++++++++++++ CMP AL,0DH JNE T55 mov byte ptr [bx],16 DEC BX call update_ledbuff call Delay1 JMP T4 T55:
cmp al,5 ja t5
t5_over:
inc bx
mov [bx],al
call update_ledbuff call Delay1 t6: call Display call read_key CMP AL,0DH JNE T66 mov byte ptr [bx],16 DEC BX call update_ledbuff call Delay1 JMP T5 T66:
cmp al,9 ja t6
t6_over:
inc bx
mov [bx],al
call update_ledbuff call Delay1 call Delay1 key_over: sti ret
;================================ read_key:
push bx push cx push dx
mov al,0ffh ;关显示口 mov dx,OUTSEG out dx,al mov bl,0 mov ah,0feh mov cx,8 key1: mov al,ah
mov dx,OUTBIT out dx,al shl al,1 mov ah,al nop nop nop nop nop nop
mov dx,IN_KEY in al,dx not al nop nop
and al,0fh jnz key2 inc bl loop key1 nkey: mov al,20h pop dx pop cx pop bx ret key2: test al,1 je key3 mov al,0