1 '***** Read data from 16key-matrix *****
2 '********** (for MIC020/B) **********
10 'EQU list
11 PPI0=$800003
12 APORT0=$800000
13 BPORT0=$800001
14 CPORT0=$800002
20 'Port Initialize
21 POKE PPI0,_10010001,B :'portC(high group) set output,(low group) set input mode.
100 'Main start
105 PRINT"123A456B789C*0#D"
110 FOR I=0 TO 3
120  POKE CPORT0,I<<4,B :'select column on 16key
121   INLINE NOP :'get delay time for row scanning
122   INLINE NOP
123   INLINE NOP
124   INLINE NOP
125   INLINE NOP
130   DAT=PEEK(CPORT0,B) :'read row data on 16key
140   FOR J=1 TO 4
150    IF SHIFTR(DAT,1,B) THEN PRINT "x"; ELSE PRINT " ";
160   NEXT J
170 NEXT I
180 PUTCH CHR$(13)
190 GOTO 110