National Instruments IEEE 1394 用户手册
Appendix A
Register-Level Programming
A-2
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Figure A-1. Explanation of Split Transactions
NI-IMAQ for IEEE 1394 Cameras 2.0 supports the 1394 Trade Association
IIDC 1.31 register specification for industrial cameras. Most of the
intricacies of register-level programming are abstracted by the driver. The
driver is responsible for manipulating camera features and
activating/deactivating the video data stream.
IIDC 1.31 register specification for industrial cameras. Most of the
intricacies of register-level programming are abstracted by the driver. The
driver is responsible for manipulating camera features and
activating/deactivating the video data stream.
Some cameras implement additional registers that are not contained in the
IIDC 1.31 specification. These advanced camera features are not natively
supported by the camera driver. To use these advanced features, you must
use the low-level, register-level access tools to communicate with the
camera.
IIDC 1.31 specification. These advanced camera features are not natively
supported by the camera driver. To use these advanced features, you must
use the low-level, register-level access tools to communicate with the
camera.
The NI-IMAQ for IEEE 1394 Cameras software provides the following
register-level primitives:
register-level primitives:
•
Read Quadlet—Reads a quadlet from a specified memory location
•
Write Quadlet—Writes a quadlet to a specified memory location
Host Computer
IEEE 1394 Camera
(1) Send Request
(5) Receive Result
(2) Receive Request and
Send Pending Packet
(3) Receive Pending Packet.
Wait for complete
(4) Complete Request
and Send Result