Register Bit Descriptions Chapter 4
GPIB-1014 User Manual 4-16 © National Instruments Corporation
Bit Mnemonic Description
5r LOK Lockout Bit
LOK is used, along with the REM bit, to indicate the status of the TLC
GPIB Remote/Local (RL) function. If set, the LOK bit indicates that
the TLC is in Local With Lockout State (LWLS) or Remote With
Lockout State (RWLS). LOK is a Non-Interrupt bit.
5w DMAO DMA Out Enable Bit
The DMAO bit must be set to allow data transfers from VMEbus
memory to the CDOR. DO IE must be clear, DMAO must be set, and
the TLC must be the active GPIB Talker when a DMAO bit is set, the
DO condition causes a data transfer request rather than an interrupt
request.
4r REM Remote Bit
This bit is true when the TLC GPIB RL function is in one of two
states: Remote State (REMS) or Remote With Lockout State (RWLS).
The TLC RL function transfers to one of these states when the System
Controller has asserted the Remote Enable line (REN), and the CIC
addresses the TLC as a Listener.
4w DMAI DMA Input Enable Bit
The DMAO bit must be set to allow data transfers from the DIR to
VMEbus memory. DI IE must be clear, DMAI must be set, and the
TLC must be an active GPIB Listener when a DMA in operation is
initiated. If DMAI is set, the DI condition causes a data transfer
request rather than an interrupt request.
3r CO Command Out Bit
3w CO IE Command Out Interrupt Enable Bit
CO is set when:
(CACS & SGNS) becomes true
CO is cleared by:
(read ISR2) + CACS* + SGNS*
Notes
CACS: GPIB Controller Active State
SGNS: GPIB Source Generate State
read ISR2: Bit is cleared immediately after it is read
CO = 1 indicates that the CDOR is empty and that another command
can be written to it for transmission over the GPIB without overwriting
a previous command.