Data Translation DT9820 Series, User Manual

Page: 63 / 112

Programming Flowcharts
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Set Up A/D Buffering
Allocate
more
buffers?
Yes
Allocate a buffer using
olDmCallocBuffer.
Put the buffer on the ready
queue using olDaPutBuffer.
Specify OL_WRP_NONE if buffers are not reused,
OL_WRP_MULTIPLE if buffers are continuously
reused when none are found on the ready queue, or
OL_WRP_SINGLE if one buffer is continuously
reused.
Specify the buffer wrapping mode
using olDaSetWrapMode.
A minimum of three buffers is recommended.
Specify the window in which to
post the messages using
olDaSetWndHandle.
Specify the width of the buffer as 4 bytes.
Specify a buffer size at least as large as the sampling
rate; for example, if you are using a sampling rate of
960 Samples/s (960 Hz), specify a buffer size of 960
by 4 bytes. For sampling rates less than
120 Samples/s, the minimum buffer size that you
should specify is 16 samples by 4 bytes. For sampling
rates greater than 240 Samples/s, the minimum buffer
size that you should specify is 128 samples by 4
bytes.