微機(jī)原理課程設(shè)計--花式跑馬燈-文庫吧資料
2025-01-22 16:29本頁面
【正文】 掃描。得到鍵值后用來判斷是那種方式來跑。8255初始化 MOV AL,91H OUT DX,AL MOV DX,0202H MOV AL,0FFH OUT DX,ALKS1: MOV DX,0204H ；讀取按鍵 MOV AL,0FH OUT DX,AL IN AL,DX AND AL,0FH CMP AL,0FH ；判斷有無鍵閉合 JZ KS1 ；若無鍵閉合則循環(huán)等待KS2: PUSH BX ；循環(huán)消除抖動 PUSH CX MOV BX,1DEL1: MOV CX,2009DEL2: LOOP DEL2 DEC BX JNZ DEL1 POP CX POP BX MOV DX,0204H ；再次判斷有無鍵閉合 MOV AL,0FH OUT DX,AL IN AL,DX AND AL,0FH CMP AL,0FH JZ KS1 MOV BL,0EFH ；初始化列碼 MOV BH,0 ；初始化列計數(shù)器AGAIN:MOV DX,0204H MOV AL,BL OUT DX,AL ；輸出列碼讀取行碼 IN AL,DX AND AL,0FH CMP AL,0FH JZ TONEXT ；該列無鍵閉合，準(zhǔn)備下一列掃描 CMP AL,0EH ；判斷該列是否第一個鍵按下 JNZ TWO MOV DFG,0 JMP FREETONEXT:JMP NEXTTWO: CMP AL,0DH ；判斷該列是否第二個鍵按下 JNZ THREE MOV DFG,4 JMP FREETHREE:CMP AL,0BH ；判斷該列是否第三個鍵按下 JNZ FOUR MOV AL,8
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