【導讀】本應用系統(tǒng)設計的目的是通過在“單片機原理及應用”課堂上學習的知識，以及查閱資料，培養(yǎng)一種自學的能力。在設計的過程中，不斷的學習，思考和同學間的相互討論，學會對常見問題的處理方法，積累設計系統(tǒng)的經驗，充分發(fā)揮教學與實踐的結合。工作打下了堅實的基礎。是測量正弦信號，方波信號及其他各種單位時間內變化的物理量。確度高，顯示直觀，經常要用到頻率計。器動態(tài)顯示6位數(shù)?；驹O計原理是直接用十進制數(shù)字顯示被測信號頻率的一種測量裝置。測量周期的方法對正弦波、方波、三角波的頻率進行自動的測量。時間基準信號發(fā)生器提供標準的時間脈沖信號，若其周期為1s，則門控電路。閘門電路由標準秒信號進行控制，當秒。結束時閘門關閉，計數(shù)器停止計數(shù)。能接受或輸出4個TTL邏輯門電路。拉升為高電平，此時可以作為輸入端使用。到高電平，此時可以用作輸入口。作為輸入口，因為內部存在上拉電阻，某個引

　　

【正文】 18 JNZ XIAN1 MOV 40H,00H MOV 41H,00H MOV 42H,00H MOV 43H,30H MOV 44H,31H MOV 45H,32H JMP XIAN XIAN1:MOV A,17H XRL A,01H JNZ XIAN2 MOV 40H,00H MOV 41H,00H MOV 42H,30H MOV 43H,31H MOV 44H,32H MOV 45H,33H JMP XIAN XIAN2:MOV A,17H XRL A,00H JNZ XIAN3 MOV 40H,00H MOV 41H,30H MOV 42H,31H MOV 43H,32H MOV 44H,33H MOV 45H,34H JMP XIAN XIAN3:MOV A,17H XRL A,03H JNZ XIAN MOV 40H,30H MOV 41H,31H MOV 42H,32H MOV 43H,33H MOV 44H,34H MOV 45H,35H XIAN:mov r0,40h mov a, @r0 JZ L20 MOV 10H,0FFH 19 MOV 15H,0FFH mov dptr,date1 movc a,@a+dptr call write2 L20:INC R0 MOV A, 10H CJNE A, 00H,PP mov a, @r0 JZ L21 PP: MOV 11H,0FFH MOV 15H,0FFH mov a, @r0 mov dptr,date1 movc a,@a+dptr call write2 L21:INC R0 MOV A, 11H CJNE A, 00H,PP2 mov a, @r0 JZ L22 PP2: MOV 12H,0FFH MOV 15H,0FFH mov a, @r0 mov dptr,date1 movc a,@a+dptr call write2 MOV A, 15H CJNE A,0FFH,L22 MOV A,00H mov dptr,XIAOSHUDIAN movc a,@a+dptr call write2 L22: INC R0 MOV A, 12H CJNE A, 00H,PP3 mov a, @r0 JZ L23 PP3: MOV 13H,0FFH mov a, @r0 mov dptr,date1 20 movc a,@a+dptr call write2 L23:INC R0 MOV A, 13H CJNE A, 00H,PP4 mov a, @r0 JZ L24 PP4: MOV 14H,0FFH mov a, @r0 mov dptr,date1 movc a,@a+dptr call write2 L24:INC R0 mov a, @r0 mov dptr,date1 movc a,@a+dptr call write2 MOV A,15H CJNE A, 00H,KHZ MOV A,00H MOV dptr,DANWEI1 JMP QUSHU KHZ:MOV dptr,DANWEI2 QUSHU:movc a,@a+dptr call write3 mov r5,4 l3:mov a,20h call write2 djnz r5,l3 ret write2: mov p0, a setb rs CLR rw clr e call delay setb e ret write3: mov r1,00h 。寫數(shù)據(jù) a2: mov a, r1 21 movc a, @a+dptr call write2 inc r1 cjne a,00h,a2 ret delay: mov r7, 255 d1: mov r6, 255 d2: djnz r6, d2 djnz r7, d1 ret date: db the frequency is,00h date1: db 30h,31h,32h,33h,34h,35h,36h,37h,38h,39h DANWEI1: DB HZ ,00h DANWEI2: DB KHZ ,00h XIAOSHUDIAN: DB .,00h