1.构建系统2.驱动代码.MODEL SMALL .8086 .stack .code .startup NMI_init: push es ;NMI中断向量初始化 xor ax, ax mov es, ax mov al, 02h xor ah, ah shl ax, 1 shl ax, 1 mov si, ax mov ax, offset NMI_service mov es:[si], ax inc si inc si mov bx, cs mov es:[si], bx pop es mov al,10110101b ;T2 16位 mode2 bcd mov dx,0406h out dx,al mov dx,0404h mov ax,1000h ;clk100KHz 1000分频 out100Hz0.01秒 out dx,al mov al,ah ;高字节 out dx,al lop: call key call disp jmp lop disp proc ;显示子程序 mov bl,m_sec and bx,000fh ;毫秒个位 mov si,bx mov al,situation[si] ;毫秒个位段码 mov bl,m_sec and bx,00f0h ;毫秒十位 mov cl,4 shr bx,cl mov si,bx mov ah,situation[si] ;毫秒十位段码 mov dx,0000h ;毫秒输出地址 out dx,ax mov bl,sec and bx,000fh mov si,bx mov al,situation[si] mov bl,sec and bx,00f0h mov cl,4 shr bx,cl mov si,bx mov ah,situation[si] mov dx,0200h ;秒输出地址 out dx,ax ret disp endp key proc near mov dx,0600h in al,dx test al,01h jnz exitkey call delay ;消抖 mov dx,0600h in al,dx test al,01h jnz exitkey inc state waitkey:in al,dx test al,01h jz waitkey ;等待按键释放 cmp state,03h jb exitkey mov state,0 exitkey:ret key endp ;fosc5MHz,T0.2us,Td ≈20ms delay proc near ;延时子程序 push bx push cx mov bx,1 ;4 del1: mov cx,5882 ;4 del2: loop del2 ;17/5 dec bx ;2 jnz del1 ;16/4 pop cx pop bx ret delay endp NMI_service: push ax cmp state,0h ;state0,时钟清0 je clear cmp state,01h ;state1,时钟走时 je start cmp state,02h ;state2,时钟停止 je stop jmp exit clear:mov m_sec,0 mov sec,0 jmp exit start:mov al,m_sec add al,1 ;毫秒1 daa mov m_sec,al cmp m_sec,00h jne exit mov m_sec,0 mov al,sec add al,1 ;秒1 daa mov sec,al cmp sec,60h jb exit mov sec,0 jmp exit stop: exit: pop ax iret .data state db 0;0_clear,1_start,2_stop m_sec db 00h sec db 00h situation db 3FH,06H,5BH,4FH,66H,6DH,7DH,07H,7FH,6FH ;共阴 sit_end$ END3.运行测试
