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Camera Operation & Features
Document No.: 04646-01
PixeLINK PL-A780
MACHINE VISION CAMERA
SYSTEM GUIDE
Copyright © 2004 PixeLINK
All Rights Reserved
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Camera Information
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Camera Name
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Descriptors
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General Purpose Outputs
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Look Up Table
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Pixel Addressing
5.1.4.1 Camera Information
A block of CSRs provides read only access to basic camera information including:
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Camera Serial Number
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FPGA Version
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Firmware Version
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Camera Description
The camera serial number is a factory set string of numbers that uniquely identifies the
camera. The FPGA Version and Firmware Version identify the hardware and firmware
versions currently loaded in the camera. The FPGA and Firmware can be updated in the
field and these entries will reflect the versions currently loaded. The FPGA and Firmware
version numbers are stored as a 32 bit word and can be decoded in the form
Byte0.Byte1.Byte2.Byte3.
The camera description is a text string, up to 256 characters long, that provides a short
description of the camera type.
5.1.4.2 Camera Name
The name of the camera can be read and set from this feature. It is a text string of up to 256
characters in length.
5.1.4.3 Descriptors
A descriptor is a list of all the camera parameters. The Descriptor feature is a way to control
camera settings between frames without communication between the host computer and the
camera. This allows for rapid changes of camera parameters in a deterministic manner.
When in rolling shutter mode, if the changes affect the sensor, the camera will drop a frame
and send the next one, effectively halving the frame rate.
Descriptors also provide information about the current camera settings. Most of the camera
settings will be known to the host computer but a few, especially the features that are set to
Auto, may change without the host’s knowledge. The descriptor structure is set up in two
parts so that all the settings that can change are in the first part and all the known and static
settings are in the second. The complete descriptor can be written or read from camera
memory. It is important to check the version of the descriptor structure in order to use the
correct structure.
The first part of the descriptor structure is always appended to each frame. For more
information on the manner and format in which the data is appended to the frame, refer to
Section 9 on page 56.
For camera control, up to 14 descriptors can be created and stored in camera memory. The
camera will apply each descriptor in turn when capturing images. When multiple descriptors
are in use, the camera will encode a synchronization number in the first 16 bytes of image
