Data Translation DT3153, Руководство пользователя

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Chapter 2
24
Acquisition Modes
The DT3153 board can acquire interlaced frames either
synchronously or asynchronously, and store them in system memory.
In a synchronous acquisition, you cannot perform another operation
until the synchronous acquisition completes. In an asynchronous
acquisition, the operation starts but gives control to you immediately,
allowing you to perform other operations while data is acquired.
Using the DT3153, you can acquire a single full frame or multiple full
frames. Single frames are stored in an area in system memory that
was either allocated to the DT3153 Device Driver during system
startup (called
device memory ) or provided by you (called host
memory ). Multiple frames are stored only in device memory.
Each buffer in memory must be large enough to hold the acquired
frame. The amount of memory required depends on the video format
(50 Hz or 60 Hz) and the storage image format (RGB or YUV) used.
The required memory size must be equal to or greater than frame
height multiplied by frame width multiplied by pixel depth for each
video format and storage image format.
Table 2 lists the maximum memory size required for each image
format and image type supported.
Table 2: Required Memory
Video Format
Storage Image
Format
Maximum Memory Required
(Bytes)
60 Hz RGB 1,228,800
YUV or RGB16 614,400
50 Hz RGB 1,769,472
YUV or RGB16 884,736