Dicon VX500, Руководство по эксплуатации, Страница: 19 / 24

October 20, 1998
Switch Control 19
Figure 15: Parallel Port Line Assignments
The following BASIC program can be used to control the VX500 from a PC printer port. The
program switches channel-by-channel from channel 1 through channel 8. If an error is
encountered, the program resets the switch. If the error persists, the program exits. The
program expects the VX500 to be connected to the printer port as outlined in Figure 15.
Depending on the speed of your PC, you may have to insert a delay after the STROBE low
commands (lines 90, 150) in order to satisfy minimum pulse width constraints.
1 REM Testing program for VX500 controlled through PC printer port (PP).
2 REM Address 379H is PP input byte (BIT3=ERROR; BIT7=BUSY).
3 REM Address 378H is PP output byte (<BIT4:BIT0>=<D4:D0>; BIT7=RESET).
4 REM Address 37AH is PP STROBE output (BIT0=STROBE).
5 REM The printer port inverts the STROBE output.
6 REM Note: Some computers use addresses 3BC, 3BD, & 3BE.
10 WAIT 1 ‘wait during power-up (970 ms min.)
20 FOR K = 1 TO 8 STEP 1 ‘step through channels 1 through 8
30 INBYTE = INP(&H379) ‘read BUSY signal
40 IF (INBYTE AND 128) <> 128
THEN GOTO 30 ‘BUSY = HIGH, check again
50 INBYTE = INP(&H379) ‘read ERROR signal
60 IF (INBYTE AND 8) = 8
THEN GOTO 130 ‘ERROR = HIGH, reset device
70 OUT &H378, K + 127 ‘send channel & RESET to data bus
80 OUT &H37A, 0 ‘set STROBE high
90 OUT &H37A, 1 ‘bring STROBE low
100 OUT &H37A, 0 ‘set STROBE high
110 NEXT K ‘do the next channel
120 STOP ‘done!
130 OUT &H378, 127 ‘set RESET low
140 OUT &H37A, 0 ‘set STROBE high
150 OUT &H37A, 1 ‘bring STROBE low
160 OUT &H37A, 0 ‘set STROBE high
170 WAIT 1 ‘wait for reset
180 INBYTE = INP(&H379) ‘check ERROR
190 IF (INBYTE AND 8) = 8 THEN STOP ‘reset failed, send for service
200 GOTO 20 ‘reset succeeded, proceed with test
GND 1
GND 2
D0 3
D1 4
D2 4
D3 6
D4 7
STROBE 8
BUSY 9
ERROR 10
RESET 11
POWER 12
1 -STROBE
2 DATA BIT 0
3 DATA BIT 1
4 DATA BIT 2
5 DATA BIT 3
6 DATA BIT 4
7 DATA BIT 5
8 DATA BIT 6
9 DATA BIT 7
10 -ACK
11 BUSY
12 PE
13 SLCT
14 -AUTO FEED
15 -ERROR
16 -INIT
17 -SLCT IN
18 GND
19-25 GND
–
+
VX500 SWITCH
PARALLEL PORT
POWER SUPPLY