HP 8112A, Operating, Programming And Servicing Manual

Page: 104 / 406

I NTR_2
Purpose
This program demonstrates how to use interrupts to service SRQs.
Comments
Setup section (llnes 1 10 - 1 20):
The interrupt service subroutine Service_srq is set up. SRQs from
interface 7 are enabled to cause an interrupt.
Main section
A
SPOLL is conducted to show the value of the STB before the
syntax error. The computer is forced to wait
2
seconds (line 190) for
the SRQ before exiting the program.
Subroutine section
The Service_srq subroutine.
This subroutine conducts a SPOLL.
Then the value and the bits which are set in the Status Byte are
printed.
10
! Name of this program : INTR_2
20
! -----------------------------------------------------------
30 This program demonstrates hov to use interrupts to service
40
! a SRQ from the HP8 1 12A .
50
60
CLEAR SCREEN
70
80
CLEAR 712
90 A=SPOLL (7 12) ! clear status byte
100
1 10
ON INTR 7 , 2 CALL Service_srq ! Setup service routine for SRQ
120 ENABLE INTR 7 ; 2
!
Enable only service requests for interrupt .
130
140 A=SPOLL (712)
150
PRINT "SPOLL before the syntax error : " ; A
160
170
PRINT "Syntax error ca.used"
180
OUTPUT 712 ; "XXX"
190 WAIT 2 ! Wait 2 seconds , to enable the HP8 1 12A to request service
200
210
PRINT " End of the ma.in program . "
220 PRINT "End of the program INTR_2 . "
230 LOCAL 712
240 END
250
260
! =================================================================
270
280
! Subrout ine for servicing the interrupts .
7
-12 Programming 'Examples