3． 系统板上硬件连线读 P1口数据到 A CC 中A CC 内容右移 4 次A CC 内容与 F0H相或A CC 内容送入 P1口XOR A,#0F0HMOV P1,A NEXT1: SETB P1.0NEX1: JB P1.5,NEXT2CLR P1.1NEXT2: SETB P1.1NEX2: JB P1.6,NEXT3CLR P1.2NEXT3: SETB P1.2NEX3: JB P1.7,NEXT4CLR P1.3 3． 系统板上硬件连线P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 P1.0 图 9.1 ID EQU 30HSP1 BIT P3.7L1 BIT P1.0 图14.1 图14.23． 系统板上硬件连线 MOV P3,#0FFHCLR P3.4MOV A,P3 NK3: CJNE A,#07H,NK4MOV KEYBUF,#3LJMP DK1NOKEY1:MOV P3,#0FFHCLR P3.5 NK7: CJNE A,#07H,NK8MOV KEYBUF,#7LJMP DK2MOV P3,#0FFHCLR P3.6NK9: CJNE A,#0DH,NK10MOV KEYBUF,#9LJMP DK3NK10: CJNE A,#0BH,NK11MOV KEYBUF,#10LJMP DK3 MOV P3,#0FFHCLR P3.7NK14: CJNE A,#0BH,NK15MOV KEYBUF,#14LJMP DK4 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; 图 6.13． 系统板上硬件连线 图 6.2DELY500: MOV R7,#250LOOP: NOP （1． 由 4X4组成 16个按钮矩阵,设计成 16 个音。
2． 可随意弹奏想要表达的音乐2． 电路原理图图22.1 低 1 DO 262#1 DO# 277低 2 RE 294低 5 SO 392# 5 SO# 415中 1 DO 523# 1 DO# 554# 2 RE# 622 图22.2 MOV P3,#0FFHCLR P3.4NK3: CJNE A,#07H,NK4MOV KEYBUF,#3LJMP DK1 MOV STH0,AMOV TH0,ANOKEY1:MOV P3,#0FFHCLR P3.5NK7: CJNE A,#07H,NK8MOV KEYBUF,#7LJMP DK2 MOV P3,#0FFHCLR P3.6NK9: CJNE A,#0DH,NK10MOV KEYBUF,#9LJMP DK3NK10: CJNE A,#0BH,NK11 NOKEY3:MOV P3,#0FFHCLR P3.7 NK14: CJNE A,#0BH,NK15MOV KEYBUF,#14LJMP DK4INC TEMPMOV A,TEMP unsigned char code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07, 科教兴国39。