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hi, i have been writing an assembly code for 89c51,which allows me to send data to lcd by keypad. But the lcd only showing me the initialize step and, no matter how i hit the keypad button,it wont show me any result.the keypad that i am using 4x4 matrix keypad. i really need someone's help and i appreciate it very much.
org 0000h //initial lcd mov a,#38h acall comnwrt mov a,#01h acall comnwrt mov a,#02h acall comnwrt mov a,#0fh acall comnwrt mov p2,#0ffh; input port k1: mov p0,#0; output port mov a,p2 anl a,#00001111B cjne a,#00001111B,k1 k2: mov a, p2 anl a,#00001111B cjne a,#00001111B,over sjmp k2 over: mov a,p2 anl a,#00001111B cjne a,#00001111B, over1 sjmp k2 over1: mov p0,#11111110B mov a,p2 anl a,#00001111B cjne a,#00001111B,row_0 mov p0,#11111101B mov a,p2 anl a,#00001111B cjne a,#00001111B,row_1 mov p0,#11111011B mov a,p2 anl a,#00001111B cjne a,#00001111B,row_2 mov p0,#11110111B mov a,p2 anl a,#00001111B cjne a,#00001111B,row_3 row_0: mov dptr,#kcode0 sjmp find row_1: mov dptr,#kcode1 sjmp find row_2: mov dptr,#kcode2 sjmp find row_3: mov dptr,#kcode3 find: rrc a jnc match inc dptr sjmp find match: clr a movc a, @a+dptr acall datawrt ljmp k1 org 300h kcode0: db '0','1','2','3' kcode1: db '4','5','6','7' kcode2: db '8','9','A','B' kcode3: db 'C','D','E','F' comnwrt: mov p1,a //send command acall delay1 clr p3.7 //connect to rs(lcd) acall delay1 setb p3.6 //connect to e(lcd) acall delay5 clr p3.6 acall delay1 ret delay1: mov r3,#50 here2: mov r4,#255 here: djnz r4,here djnz r3,here2 ret delay5:mov r3,#250 here3: mov r4,#255 here1: djnz r4,here1 djnz r3,here3 ret delay10:mov r3,#255 here4: mov r4,#255 here5: djnz r4,here5 djnz r3,here4 ret datawrt: mov p1,a //send data to lcd acall delay1 setb p3.7 acall delay1 setb p3.6 acall delay1 clr p3.6 acall delay10 ret end