Theory of Operation Chapter 6
GPIB-1014 User Manual 6-6 © National Instruments Corporation
• Enabling the Release On Request feature. Writing a 0 to this bit (ROR*) enables the Release
On Request feature while writing a 1 disables the Release On Request feature. This bit is set
to 1 during reset or power up. This bit is used by the DTB Requester circuitry.
• Selecting the direction of the DMA transfer. Writing a 1 to this bit (DIR) indicates that the
transfer direction is from GPIB to VMEbus memory, while writing a zero indicates that the
direction is from VMEbus memory to the GPIB. This bit is used by the GPIB
Synchronization and Interrupt Control circuitry.
• Writing any value to this register resets the circuitry which detects GPIB synchronization
after a DMA transfer. (For more information, see GPIB Synchronization and Interrupt
Control later in this chapter).