1. 實驗任務 如圖4.14.2所示,用AT89S51的并行口P1接4×4矩陣鍵盤,以P1.0-P1.3作輸入線,以P1.4-P1.7作輸出線;在數碼管上顯示每個按鍵的“0-F”序號。對應的按鍵的序號排列如圖4.14.1所示 ͼ4.14.1 2. 硬體電路原理圖 ͼ4.14.2 3. 系統板上硬體連線 (1. 把“單片機系統“區域中的P3.0-P3.7埠用8芯排線連接到“4X4行列式鍵盤”區域中的C1-C4 R1-R4埠上; (2. 把“單片機系統”區域中的P0.0/AD0-P0.7/AD7埠用8芯排線連接到“四路靜態數碼顯示模塊”區域中的任一個a-h埠上;要求:P0.0/AD0對應著a,P0.1/AD1對應著b,……,P0.7/AD7對應著h。 4. 程序設計內容 (1. 4×4矩陣鍵盤識別處理 (2. 每個按鍵有它的行值和列值 ,行值和列值的組合就是識別這個按鍵的編碼。矩陣的行線和列線分別通過兩并行介面和CPU通信。每個按鍵的狀態同樣需變成數字量“0”和“1”,開關的一端(列線)通過電阻接VCC,而接地是通過程序輸出數字“0”實現的。鍵盤處理程序的任務是:確定有無鍵按下,判斷哪一個鍵按下,鍵的功能是什麼;還要消除按鍵在閉合或斷開時的抖動。兩個并行口中,一個輸出掃描碼,使按鍵逐行動態接地,另一個并行口輸入按鍵狀態,由行掃描值和回饋信號共同形成鍵編碼而識別按鍵,通過軟體查表,查出該鍵的功能。 5. 程序框圖 ͼ4.14.3 6. 彙編源程序 KEYBUF EQU 30H ORG 00H START: MOV KEYBUF,#2 WAIT: MOV P3,#0FFH CLR P3.4 MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY1 LCALL DELY10MS MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY1 MOV A,P3 ANL A,#0FH CJNE A,#0EH,NK1 MOV KEYBUF,#0 LJMP DK1 NK1: CJNE A,#0DH,NK2 MOV KEYBUF,#1 LJMP DK1 NK2: CJNE A,#0BH,NK3 MOV KEYBUF,#2 LJMP DK1 NK3: CJNE A,#07H,NK4 MOV KEYBUF,#3 LJMP DK1 NK4: NOP DK1: MOV A,KEYBUF MOV DPTR,#TABLE MOVC A,@A+DPTR MOV P0,A DK1A: MOV A,P3 ANL A,#0FH XRL A,#0FH JNZ DK1A NOKEY1: MOV P3,#0FFH CLR P3.5 MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY2 LCALL DELY10MS MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY2 MOV A,P3 ANL A,#0FH CJNE A,#0EH,NK5 MOV KEYBUF,#4 LJMP DK2 NK5: CJNE A,#0DH,NK6 MOV KEYBUF,#5 LJMP DK2 NK6: CJNE A,#0BH,NK7 MOV KEYBUF,#6 LJMP DK2 NK7: CJNE A,#07H,NK8 MOV KEYBUF,#7 LJMP DK2 NK8: NOP DK2: MOV A,KEYBUF MOV DPTR,#TABLE MOVC A,@A+DPTR MOV P0,A DK2A: MOV A,P3 ANL A,#0FH XRL A,#0FH JNZ DK2A NOKEY2: MOV P3,#0FFH CLR P3.6 MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY3 LCALL DELY10MS MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY3 MOV A,P3 ANL A,#0FH CJNE A,#0EH,NK9 MOV KEYBUF,#8 LJMP DK3 NK9: CJNE A,#0DH,NK10 MOV KEYBUF,#9 LJMP DK3 NK10: CJNE A,#0BH,NK11 MOV KEYBUF,#10 LJMP DK3 NK11: CJNE A,#07H,NK12 MOV KEYBUF,#11 LJMP DK3 NK12: NOP DK3: MOV A,KEYBUF MOV DPTR,#TABLE MOVC A,@A+DPTR MOV P0,A DK3A: MOV A,P3 ANL A,#0FH XRL A,#0FH JNZ DK3A NOKEY3: MOV P3,#0FFH CLR P3.7 MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY4 LCALL DELY10MS MOV A,P3 ANL A,#0FH XRL A,#0FH JZ NOKEY4 MOV A,P3 ANL A,#0FH CJNE A,#0EH,NK13 MOV KEYBUF,#12 LJMP DK4 NK13: CJNE A,#0DH,NK14 MOV KEYBUF,#13 LJMP DK4 NK14: CJNE A,#0BH,NK15 MOV KEYBUF,#14 LJMP DK4 NK15: CJNE A,#07H,NK16 MOV KEYBUF,#15 LJMP DK4 NK16: NOP DK4: MOV A,KEYBUF MOV DPTR,#TABLE MOVC A,@A+DPTR MOV P0,A DK4A: MOV A,P3 ANL A,#0FH XRL A,#0FH JNZ DK4A NOKEY4: LJMP WAIT DELY10MS: MOV R6,#10 D1: MOV R7,#248 DJNZ R7,$ DJNZ R6,D1 RET TABLE: DB 3FH,06H,5BH,4FH,66H,6DH,7DH,07H DB 7FH,6FH,77H,7CH,39H,5EH,79H,71H END 7. C語言源程序 #include unsigned char code table[]={0x3f,0x06,0x5b,0x4f, 0x66,0x6d,0x7d,0x07, 0x7f,0x6f,0x77,0x7c, 0x39,0x5e,0x79,0x71}; unsigned char temp; unsigned char key; unsigned char i,j; void main(void) { while(1) { P3=0xff; |