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SRO (Cont'd)
Example 2. Front Panel SRO
The front panel SRO feature of the 3468A
provides you with a way of manually
interrupting the controller from the multimeter front panel. This feature is enabled
by setting bit 4 of the SRO mask, command
"M20".
Once this is done, pressing
the 3468A front panel SRO key causes the 3468A
to request service (SRQ) from
the controller.
The SRO
annunciator
turns on in the display until the controller
responds by doing a serial poll or the CLEAR command.
|
FRUNT
PANEL
SRe
EXAMPLE
'
-he-
$5
VERSION
A
| 3463R
AT
ADDRESS
9at
46
REMOTE
9
Sa
QUTPUT
9@1
: "Mea"
6@
ON
INTR
9 GOSUB
1868
7a@ ENABLE
INTR
958
68
1 The
body
of
the
Program
30
es
here
996
END
19G@
P=SPOLL¢3a1)
1410
IF
BIT¢P:.4)
THEN
DISP
"SRG
key
Pressed"
1926
RETURN
Line
50
60
70
80-990
1000
1010
1020
74
Description
The "M20"
statement sets the 3468A to
respond to the front panel SRQ key.
This tells the computer
where
to go (line
1000) when an SROQ interrupt occurs.
ENABLE INTR actually allows the controller
to respond to interrupts.
These
lines contain
the body of the pro-
gram.
SPOLL
returns
3468A
status
byte
to
variable P, It also clears the status register.
Bit 4 of the status byte (P) is checked to
make sure it is a" 1". If it is, the message
SRQ KEY PRESSED
is displayed. If it isn't,
then something else caused the interrupt.
This line returns program control to where
it was interrupted.
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