National Instruments GPIB-SCSI-A, Руководство пользователя

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Chapter 5 S Mode Functions
© National Instruments Corp. 5-79 GPIB-SCSI-A User Manual
rsp - Request (Conduct) a Serial Poll
Type: Serial Poll function
Purpose: Use
rsp
if you want to conduct a serial poll to obtain device-
specific status information from one or more devices.
Format:
Bit 7 6 5 4 3 2 1 0
Byte
0 Opcode = D3H
1 GPIB Primary Address Reserved
2 GPIB Secondary Addr. (Opt.) Mode Reserved
3 Reserved
4 Reserved
5 Reserved
Remarks: The argument GPIB Primary Address along with GPIB
Secondary Address specifies the address of the device the
GPIB-SCSI-A serial polls. To indicate that GPIB Secondary
Address contains a valid device address, Mode is set to 1.
rsp
serial polls the specified device to obtain its status byte.
If bit 6 (hex 40 or RQS bit) of a device response is set, its
status response is positive – that is, the device is requesting
service. The interpretation of each device response, other than
the RQS bit, is device specific. For example, the polled
device might set a particular bit in the response byte to
indicate that it has data to transfer, and another bit to indicate a
need for reprogramming. Consult your device documentation
for interpretation of the response byte.
If a device does not respond in the timeout period, the
GPIB-SCSI-A returns -1 (FF hex) and records the EABO
error. The time limit is set to 1/10 sec.