Measurement-computing Analyzer488 Manuale Utente Scaricare il pdf (Pagina 168)

Section 4 Serial Controller

4.74

SPOLL

The Serial Poll command,

SPOLL

, performs a Serial Poll of bus devices and

responds with number from

255

representing the decimal equivalent of the eight-

bit device response. Serial Polls are normally performed in response to assertion of

the Service Request (SRQ) bus signal by some bus device. 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.

SPOLL

is issued with multiple addresses specified, the Analyzer488 will

perform a serial poll on each device and send the output of each response to the serial

port with the serial output terminator(s) appended.

With no bus address specified, the

SPOLL

command returns the external SRQ

status. If the SRQ line is asserted, the Analyzer488 will return a "64". If it is not

asserted, the Analyzer488 will return a "0".

This command does not have a query option.

TYPE High Level Controller command

SYNTAX SPOLL

[addr[,addr…]]

addr is an IEEE 488 bus device address

RESPONSE 0 or 64 (without

addr

)

0 to 255 (with

addr

)

MODE High Level Controller

BUS STATES ATN•UNL, MLA, TAG, SPE, *ATN, data, ATN•SPD, UNT

QUERY None

RESPONSE

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Measurement-computing Analyzer488 Manuale Utente Pagina 168