Communication between the Host Computer and the NI Motion Controller

NI-Motion VI

Communication between the Host Computer and the NI Motion Controller

The host computer communicates with the NI motion controller through a number of I/O port addresses on the ISA or PCI bus.

At the controller's base address is the primary bidirectional data transfer port. This port supports FIFO data passing in both send and readback directions. The NI motion controller has both a command buffer for incoming commands and a Return Data Buffer (RDB) for return data.

At offsets from the controller's base address are two read-only status registers. The flow of communications between the host and the NI motion controller is controlled by handshaking bits in the Communications Status Register (CSR). The MCS register provides instantaneous motion status of all axes.

Board Identification Parameter

Packets, Handshaking, and FIFO Buffers

Return Data Buffer