【正文】 RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 1 1 ↓等待100us RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 1 1 N F ↓檢查忙標志或延時40us RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 0 0 1 0 ↓檢查忙標志或延時40us RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 0 0 0 0 0 1↓檢查忙標志或延時40 us RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 0 0 0 0 0 0 0 1 I/D S↓ 初 始 化 結(jié) 束↓檢查忙標志或延時40 圖211 八位接口初始化流程圖三、軟件設計（一）程序流程圖開 始系統(tǒng)初始化頻率測量量程自動轉(zhuǎn)換有效數(shù)位判別測量數(shù)據(jù)顯示開 始浮點數(shù)到BCD碼中斷服務程序周期測量f=1/T浮點數(shù)格式化圖31 數(shù)字頻率計程序流程圖（二）匯編語言源程序RS BIT ； RW BIT ； E BIT ； ORG 0000H LJMP MAIN ORG 002BH LJMP IT1MAIN:MOV P0,01H 。清除屏幕 ACALL ENABLE MOV P0,01H 。8位點陣方式 ACALL ENABLE MOV P0,0cH 。移動光標 ACALL ENABLE MOV P0,80H 。第一行的位置 CALL ENABLE MOV DPTR,DATE CALL WRITE3 MOV P0,0C0H 。溢出進位 JMP CHAJINWEI:CLR TR1 MOV TH1,high(6553650000) MOV TL1,low(6553650000) SETB TR1 INC R3 MOV A,R3 CJNE A,20,CHA CLR TR0 CLR TR1 MOV R3,00 MOV R2,TH0 MOV R6,TL0 LCALL ZHUAN LCALL WRITE MOV TL0,00H MOV TH0,00H JIP CHALZHUAN:MOV A,R2CLR CMOV 20H,00HMOV 21H,00HMOV 22H,00HMOV 24H, 00HMOV 25H,00HMOV R3,10HNEXT: RLC AMOV R2,AMOV A,20HADDC A,20HDA AMOV 20H,AMOV A,21HADDC A,21HDA AMOV 21H,AMOV A,22HADDC A,22HDA AMOV 22H,AMOV A,R2DJNZ R3,NEXTMOV A,R6CLR CMOV R3,08HNEXT1: RLC AMOV R6,AMOV A,24HADDC A,24HDA AMOV 24H,AMOV A,25HADDC A,25HDA AMOV 25H,AMOV A,R6DJNZ R3,NEXT1CLR CMOV A,24HADDC A,20HDA AMOV 20H,AMOV A,25HADDC A,21HDA AMOV 21H,AMOV A,22HADDC A,00HDA AMOV 22H,AMOV A,22HANL A,0FHMOV 31H,AMOV A,22HMOV A,0F0HSWAP AMOV 30H,AMOV A,21HANL A,0F0HSWAP AMOV 32H,AMOV A,21HANL A,0FHMOV 33H,AMOV A,20HANL A,0F0HSWAP AMOV 34H,AMOV A,20HANL A,0FHMOV 35H,ARET。LCD顯示。寫數(shù)據(jù) MOV 11H,00H MOV 12H,00H MOV 13H,00H MOV 14H,00H MOV 15H,00H MOV 16H,00H MOV P0,0CH CALL ENABLE MOV P0,0C0H 。寫數(shù)據(jù) A2: MOV A, R1 MOV A, A+DPTR CALL WRITE2 INC R1 CJNE A,00H,A2 RET DELY: MOV R7, 255 D1: MOV R6, 255 D2: DJNZ R6, D2 DJNZ R7, D1 RET DATE: DB THE FREQUENCY IS,00H DATA1: DB 30H,31H,32H,33H,34H,35H,36H,37H,38H,39HDANWEI1: DB HZ ,00HDANWEI2: DB KHZ ,00H XIAOSHUDIAN: DB .,00HEND四、總結(jié)本文介紹了使用單片機系統(tǒng)和匯編語言設計數(shù)字頻率計的方法，并下載到單片機中組成實際電路，這樣可以簡化硬件的開發(fā)和制造過程，而且使硬件體積大大縮小，并提高了系統(tǒng)的可靠性。所以我們下一步的工作就是改進整形電路的整形效果和抗干擾性能，盡最大可能減小信號整形帶來的誤差。實驗[7] 。[9] 。使我在現(xiàn)代電子設計理念有一個較全面的了解，學到扎實的技能，增強了自身的創(chuàng)造實踐能力，為日后成為合格的應用型人才打下良好的基礎。在此，我忠心感謝王棟老師的指導和支持。第 1 頁