Measurement Computing Micro 488/EX rev.2.1 - Manual (Page 147)

Section 5 Command Descriptions
5.77
SPOLL
In Active Controller mode the SPOLL command performs a Serial Poll of the bus
device specified and responds with 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. If multiple addresses are
specified, the Micro488/EX will serial poll each device in sequence and output each
device's response to the serial port with the serial output terminator(s) appended.
In Active Controller mode, with no bus address specified, the SPOLL command
returns the external SRQ status. If the SRQ line is asserted, the Micro488/EX will
return a "64". If it is not asserted, the Micro488/EX will return a "0".
In Peripheral mode the SPOLL command is issued without an address and returns
Macro488's own serial poll status. If rsv (DIO7, decimal value 64) is set, then the
Micro488/EX has not been Serial Polled since the issuing last REQUEST command.
rsv is reset whenever the Micro488/EX is Serial Polled by the Controller.
SYNTAX SPOLL [addr[,addr…]]
or
SP
[addr[,addr…]]
addr is the bus device(s) to be Serial Polled
RESPONSE 0 or 64 (without addr)
0 to 255 (with addr)
MODE CA
BUS STATES ATN•UNL, MLA, TAG, SPE, *ATN, data, ATN•SPD, UNT
EXAMPLES PRINT#1,"SPOLL 16" Serial Poll device 16
INPUT#1,SPSTAT Receive the Spoll status
IF SPSTAT AND 64 THEN… Test rsv…