Teledyne SP Devices ADQ7DC, Manual

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19-2233 PC2
2019-02-01
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ADQ7DC Manual
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7.4.3 Transfer buffers
The data transfer buffers are the kernel buffers in Figure 33 and Figure 35 . These buffers are used by
the DMA and the ADQAPI to transfer the data from the ADQ digitizer to the host PC.
The transfer buffers are owned and managed by the ADQAPI, but the user sets the size and number of
buffers with the command
SetTransferBuffers
.
7.4.4 User’s buffers
The user’s buffers in Figure 33 and Figure 35 are allocated and managed by the user. The ADQAPI
recreates the data record and puts the result in these buffers.
Create the buffers using
malloc
. Then provide the pointers of these buffers to the ADQAPI through the
commands
GetDataStreaming
(for triggered streaming Section 7.4.1 ) or
GetDataWHTS
(for multi-record
Section 7.4.2 ).
The user’s buffers consist of two sets of buffers; one for header information and one for data. The
header is always 40 bytes per record and the content is described in
Section 7.6 . The data buffer size
is depending on the amount of data in each record. For FWDAQ, the record size is always constant and
the buffer size can be set to match the record size. For FWPD, the record length may vary between
records. The data buffer size cannot be matched to the data. The example code in ADQAPI_example
1
illustrate how to handle data buffers in general.
7.5 Users application software consuming data
The users application can consume the data in different ways. Some examples are in Figure 37 . The
component “disk” is used for illustrating the end point for the data. It may also be a display or some
other device such as an alarm.
Figure 36: Timing of user-scheduled data transfer.
1. The ADQAPI_example is found in the folder installation of the digitizer software.
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