Advanced Interrupt Programming - HP 82479A Owner's Manual

Getting Started
2.10.6 Advanced Interrupt Programming
Advanced interrupt driven applications which need to service interrupts from more than one device are
possible using the keywords in the HP 82401A HP-IL Interface and the Data Acquisition Pac. The
following example illustrates the combined use of the HP 3421A and the HP 346 8A Digital Multimeter in
an interrupt-driven environment. The program monitors both devices and reads a voltage "on demand".
In this program the HP-71 waits for a service request from either the HP 3421A or the HP 3468A and
takes a voltage reading on the instrument that sent the request. The example assumes the HP 3421A has
multiplexer cards in slots 0 and 1, and a digital I/O card in slot 2. A switch connected to input channel 20
can momentarily raise the input voltage to S volts, causing an interrupt. The HP 3468A sends an SRQ
when the [SRQ] button on the front panel is pressed.
1a V=DENVADDRE CS "HF S485" 2 Find HP 3468A
cl THITE421 @ H=DEVADDECADRE=421$0 Find HP 3421A
mE SETTERS Set HP 3421A intr mask
GE OUTFIT 2% fs "MEEFIHSTIDEMAITIHG" Set HP 3468A for front panel
Service request and dc volts
5
EE TOR
CECMONITOR HIGH 268 HP 3421A starts
mE OM IHTE GOTO 128 Tell HP-71 where to go
HE EMABLE IMTRE = ® RUTOIODY OH Allow HP-71 to respond
1a IF EEYSH#"0" THEW 186 ELSE "QUIT! Monitor keyboard
118 1
lz IF HOT BITCRERDIMTE.Zy THEM TOF! Confirm SRQ interrupt
1z28 |
14a 1 HF24e2 service rout ine
IY SE]WT IE Did HP 346 8A source SRQ?
led IF HOT BITCS. 42 THEM 228 Goto HP 3421A if not.
Lye ODIs TIMES: " HP2483 Voltage! Vs Display time, source,
lag ENTER 2% s/ ® DISF H and voltage.
Lae QUTHUOT av s"D2MAITIHG" Refresh HP 3468A display
SEE GOTO TOR! Re-enable interrupts
ole
aod b b HFE421 service rout ine
Sol S=EROLLLcH Did HP 3421A source SRQ?
ade TF HOT BITOS. 22 THEM TOR! Re-enable intrs if not
Soi OIF TIMES: " HP2421 Voltage: "30CWOLTSCLE Display voltage
Sel GOTO TOR! Re-enable interrupts
semTTT
aE OFF THTRE @ OUTFUOT 8 "De Clear devices
Ade OIF "Dome" ® EMD
The program enables the service request masks in both the HP 3468A and the HP 3421A. The HP-71
receives an SRQ when the [SRQ] button on the HP 3468A is pressed or channel 20 goes high in the
HP 3421A. Line 120 confirms that the interrupt is actually a device requesting service.
The HP 3468A is polled in line 150 to determine if it was the source of the SRQ. If bit 4 of the
HP 3468A status is clear, the program branches to the HP 3421A service routine. Otherwise, a voltage