National Instruments IEEE 1394 用户手册
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Register-Level Programming
This appendix explains how to access and program register locations using
the NI-IMAQ for IEEE 1394 Cameras software, and discusses the caveats
involved in programming registers.
the NI-IMAQ for IEEE 1394 Cameras software, and discusses the caveats
involved in programming registers.
Introduction
All IEEE 1394 cameras communicate to the host computer through register
maps. The register map reflects the system memory located on the
IEEE 1394 camera. The register map allows the host computer to read and
write information with minimal overhead.
maps. The register map reflects the system memory located on the
IEEE 1394 camera. The register map allows the host computer to read and
write information with minimal overhead.
The host computer sends asynchronous messages over the IEEE 1394 bus
to the connected camera. When the data is written into memory on the
IEEE 1394 camera, the camera processes the incoming request. If possible,
the camera responds immediately. Otherwise, a pending transaction
message is returned. When the pending request is completed, the
IEEE 1394 camera returns the results of the request.
to the connected camera. When the data is written into memory on the
IEEE 1394 camera, the camera processes the incoming request. If possible,
the camera responds immediately. Otherwise, a pending transaction
message is returned. When the pending request is completed, the
IEEE 1394 camera returns the results of the request.