
7
Example
2
-
Status
Registers
and
Queues
Example
2
-
Status
Registers
and
Queues
Function
This
program
sends
a
commands
and
queries
typed
in
by
the
user
.
The
contents
of
the
status
byte
and
the
standard
event
status
register
are
displayed.
These
registers
are
updated
for
each
new
command,
and
each
time
a
Service
ReQuest
(SRQ)
occurs
.
The
number
of
the
most
recent
error
,
and
the
most
recent
contents
of
the
output
queue
is
also
displayed.
Listing
10
!--------------------------------------------------
20
!
30
!
HP
8169A
Programming
Example
2
40
!
50
!
Status
Structure,
and
a
useful
self
learning
tool
60
!
70
!--------------------------------------------------
80
!
90
!
Declarations
and
initializations
100
!
110
INTEGER
Value,Bit,Quot,Xpos,Ypos
120
DIM
Inp$[100]
130
DIM
A$[300]
140
Pol=724
150
ON
INTR
7
GOSUB
Pmm_srq
160
!
170
!
Mask
the
registers
180
!
190
OUTPUT
Pol;"*SRE
248;*ESE
255"
The
*SRE
248
command
enables
bits
7
(Operation
Status
Summary),
5
(ESB),
4
(MA
V),
and
3
(Questionable
Status
Summary)
in
the
status
byte
(bit
6
(SRQ)
cannot
be
disabled
in
this
register).
The
*ESE
255
command
enables
all
of
the
bits
in
the
Event
Status
R
egister
.
200
!
210
!
Set
up
the
screen
220
!
230
CLEAR
SCREEN
240
TABXY(40,3);"Status
Byte"
250
TABXY(4,1);"
OPS
SRQ
ESB
MAV
QUE"
260
TABXY(4,2);"
+---+---+---+---+---+---+---+---+"
270
TABXY(4,3);"
:
:
:
:
:
:
:
:
:"
280
TABXY(4,4);"
+---+---+---+---+---+---+---+---+"
290
TABXY(4,5);"
^"
Programming
Examples
7-3