DECLARE SUB WAITER ()
DECLARE SUB PORTOUT (PORT AS INTEGER, BITS AS INTEGER)
DECLARE SUB BYTEOUT (BITS AS INTEGER)
COMMON SHARED CONTRL%, PORTDAT%, PORTST%, PORTCON%
COMMON SHARED STB%, ATF%, INTNEG%, SEL%
10 PRINT "mship test 3 - toggle STROBE per data"
15 PORTDAT% = &H378
16 PORTST% = PORTDAT% + 1
17 PORTCON% = PORTDAT% + 2
20 STB% = 1
21 ATF% = 2
22 INTNEG% = 4
23 SEL% = 8
29 REM INTNEG IS ACTIVE HIGH, OTHERS LOW
50 CONTRL% = 0
100 CONTRL% = STB% + ATF% + 0 + SEL5
101 CALL PORTOUT(PORTCON%, CONTRL%)
102 FOR I = 1 TO 10
103 BITS% = I
104 CALL BYTEOUT(BITS%)
109 NEXT I
120 REM
130 CONTRL% = STB% + ATF% + 0 + SEL5
135 CALL PORTOUT(PORTCON%, CONTRL%)
199 END

400 SUB BYTEOUT (BITS AS INTEGER)
401 REM TOGGLE STB ONLY
425 CONTRL% = STB% + ATF% + 0 + SEL%
426 REM CONTROL OUTPUTS ALL LOW
430 CALL PORTOUT(PORTCON%, CONTRL%)
440 CALL PORTOUT(PORTDAT%, BITS%)
450 CONTRL% = 0 + ATF% + 0 + SEL%
451 REM STB RISES TO CLOCK
460 CALL PORTOUT(PORTCON%, CONTRL%)
END SUB

500 SUB PORTOUT (PORT AS INTEGER, BITS AS INTEGER)
510 P$ = HEX$(PORT)
511 B$ = HEX$(BITS)
513 OUT PORT, BITS
515 PRINT "PORT="; P$, "BYTE="; B$
520 CALL WAITER
END SUB

600 SUB WAITER
620 ST% = TIMER
621 FOR I = 1 TO 10000
622 T% = TIMER
624 IF T% > ST% THEN GOTO 629
626 NEXT I
629 REM
END SUB