National Instruments Corporation GPIB-1014P User Manual page 47

Register Bit Descriptions
Bit Mnemonic
6r APT
6w APT IE
GPIB-1014P User Manual
Description
undefined: GPIB command not automatically recognized and
executed by TLC
ACDS: GPIB Accept Data State
CPT ENAB: AUXRB[0]w
UDPCF: Undefined primary command function (see below)
SCG: GPIB Secondary Command Group message
pon: power on reset
TAG: GPIB Talk Address Group message
LAG: GPIB Listen Address Group message
Read ISR1: Bit is cleared immediately after it is read
UDPCF is set on:
[UCG + ACG & (TADS + LADS)] & undefined
& ACDS & CPT ENAB
UDPCF is cleared on:
[(UCG + ACG) & defined + TAG + LAG]
& ACDS + (-CPT ENAB) + pon
The CPT bit flags the occurrence of a GPIB command not recognized by
the TLC, and all following GPIB secondary commands when the
Command pass-through feature is enabled by the CPT ENAB bit,
AUXRB[0]w. Any GPIB command message not decoded by the TLC
is treated as an undefined command (for example, the Go To Local
command, GTL). However, any addressed command is automatically
ignored when the TLC is not addressed.
Undefined commands are read using the CPTR. The TLC holds off the
GPIB Acceptor Handshake in the Accept Data State (ACDS) until the
Valid auxiliary command function code, octal 017, is written to the
AUXMR. If the CPT feature is not enabled, undefined commands are
simply ignored.
Address Pass-Through Bit
Address Pass-Through Interrupt Enable Bit
APT is set by:
ADM1 & ADM0 & (TPAS + LPAS) &
SCG & ACDS
APT is cleared by:
pon + (Read ISR1)
Notes:
ADM1: Address Mode Register bit 1, ADMR[1]w
ADM0: Address Mode Register bit 0, ADMR[0]w
4-10
Section Four
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