106 API Command Reference
Personal488 User's Manual For Windows95 and Windows NT
Status
Syntax
INT WINAPI Status(DevHandleT devHandle, IeeeStatusPT result);
devHandle
refers to either an IEEE 488 interface or an external device. If
devHandle
refers to an external device,
Status
acts on the hardware interface to which the
external device is attached.
result
is a pointer to a
Status
structure.
Returns
-1
if error
Mode
Any
Bus States
None
Example
result = Status(ieee,&StatusResult);
if (statusResult.transfer == TRUE) {
printf(“We have a transfer in progress\n”);
} else {
printf(“There is no transfer in progress\n”);
}
See Also
GetError, SPoll
The
Status
command returns various items detailing the current state of Driver488. They are
returned in a data structure, based on the following table:
Status Item
Flag
Values and Description
Controller Active
.CA
TRUE
: Active Controller,
FALSE
: Not CA.
System Controller
.SC
TRUE
: System Controller,
FALSE
: Not SC.
Primary Bus Address
.Primaddr
0
to
30
: Two-digit decimal number.
Secondary Bus Address
.Secaddr
0
to
31
: Two-digit decimal number, or
-1
if no address.
Address Change
.addrChange
TRUE
: Address change has occured,
FALSE
: Not so.
Talker
.talker
TRUE
: Talker,
FALSE
: Not Talker.
Listener
.listener
TRUE
: Listener,
FALSE
: Not Listener.
ByteIn
.bytein
TRUE
: Byte in, ready to read,
FALSE
: Not so.
ByteOut
.byteout
TRUE
: Byte out, ready to output,
FALSE
: Not so.
Service Request
.SRQ
TRUE
: SRQ is asserted,
FALSE
: SRQ is not asserted.
Triggered
.triggered
TRUE
: Trigger command received,
FALSE
: Not so.
Cleared
.cleared
TRUE
: Clear command received,
FALSE
: Not so.
Transfer in Progress
.transfer
TRUE
: Transfer in progress,
FALSE
: Not so.
These
Status
items are more-fully described in the following paragraphs:
•
The
Controller Active
flag (
.CA
) is true if Driver488 is the Active Controller. If Driver488 is not
the System Controller, then it is initially a Peripheral and it becomes a controller when Driver488
receives control from the Active Controller.
•
The
System Controller
flag (
.SC
) is true if Driver488 is the System Controller. The System
Controller mode may be configured during installation or by using the SysController command.
•
The
Primary Bus Address
(
.Primaddr
) is the IEEE 488 bus device primary address assigned to
Driver488 or the specified device. This will be an integer from
0
to
30
. The
Secondary Bus
Address
(
.Secaddr
) is the IEEE 488 bus device secondary address assigned to the specified
device. This will be either
-1
to indicate no secondary address, or an integer from
0
to
31
. Note
that the interface device can never have a secondary address.
•
The
Address Change
indicator (
.addrChange
) is set whenever Driver488 become a Talker,
Listener, or the Active Controller, or when it becomes no longer a Talker, Listener, or the Active
Controller. It is reset when
Status
is read. The
Talker
(
.talker
) and
Listener
(
.listener
)
flags reflect the current Talker/Listener state of Driver488. As a Peripheral, Driver488 can check
this status to see if it has been addressed to Talk or addressed to Listen by the Active Controller.
In this way, the desired direction of data transfer can be determined.
Summary of Contents for OMB-PER-488/W95
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