104 API Command Reference
Personal488 User's Manual For Windows95 and Windows NT
SPoll
Syntax
INT WINAPI SPoll(DevHandleT devHandle);
devHandle
refers to either an interface or a specific external device.
Returns
-1
if error
otherwise,
0
or
64
(hardware interface) in the range
0
to
255
(external device)
Mode
Any
Bus States
ATN
••
UNL, MLA, UNT, TAG, SPE, *ATN, ATN
••
SPD, UNT
Examples
errorcode = SPoll(ieee);
Returns the internal
SRQ
status
errorcode = SPoll(dmm);
Returns the Serial Poll response of the specified
device
See Also
SPollList, PPoll
In Active Controller mode, the
SPoll
(Serial Poll) command performs a Serial Poll of the bus device
specified and responds with a number from
0
to
255
representing the decimal equivalent of the eight-
bit device response. If
rsv
(
DIO7
, decimal value
64
) is set, then that device is signaling that it requires
service. The meanings of the other bits are device-specific.
Serial Polls are normally performed in response to assertion of the Service Request (
SRQ
) bus signal by
some bus device. In Active Controller mode, with the interface device specified, the
SPoll
command
returns the internal
SRQ
status. If the internal
SRQ
status is set, it usually indicates that the
SRQ
line is
asserted. Driver488 then returns a
64
. If it is not set, indicating that
SRQ
is not asserted, then
Driver488 returns a
0
. With an external device specified,
SPoll
returns the Serial Poll status of the
specified external device.
In Peripheral mode, the
SPoll
command is issued only to the interface, and returns the Serial Poll
status. If
rsv
(
DIO7
, decimal value
64
) is set, then Driver488 has not been Serial Polled since the
issuing last
Request
command. The
rsv
is reset whenever Driver488 is Serial Polled by the
Controller.
Summary of Contents for OMB-PER-488/W95
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