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8.3 Interface Outline
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8.3.10 Input Buffer
NOTE
8.3.11 Status Model
Generation of service
request (SRQ)
Represents standard event register
Data is present in the output queue
bit 7
bit 5
bit 4 bit 3 bit 2 bit 1 bit 0
Unused
ESB MAV
Unused
ESB2 ESB1 ESB0
bit 6
SRQ
MSS
Logical sum
&
& & & & &
Bits represent corresponding event register
Status byte register (STB)
Service request enable register (SRER)
bit 7 bit 6
bit 5
bit 4 bit 3 bit 2 bit 1 bit 0
Unused
×
ESB MAV
Unused
ESB2 ESB1 ESB0
・・・ ・・・・・・・・・・・ ・・・
The 3332 has an input buffer of 1000 bytes capacity.
Messages which are received are put into this buffer and executed in order.
If the data accumulated in this buffer exceeds 300 bytes the buffer becomes
full, and until a space again becomes available in the buffer the GP-IB
interface bus goes into the waiting state.
･ Ensure that the length of a single command does not exceed 1,000 bytes.
･ When using XON/XOFF or hardware handshaking with the RS-232C
interface, limit the length of a single command to 750 bytes.
In its implementation of the serial polling function using service requests, the
3332 employs the status model specified by IEEE 488.2.
The term "event" refers to any phenomenon which generates a service
request.
Generation of service requests
The status byte register holds information relating to the event registers and
the output queue. It is further possible to use the service request enable
register as a mask to select the items required. If any of the bits selected by
the mask becomes 1, bit 6 (the master summary status or MSS bit) is also
set to 1, an SRQ message is generated, and this generates a service request.
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