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7
ACQUISITION CONTROL
The acquisition control consists of two partly independent parts;
•
Acquisition process: acquisition of data in a record int the DRAM of the digitizer
•
Transfer process: transfer data from the DRAM of the digitizer to host PC.
Figure 25
shows the flow of data through acquisition and data transfer.
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DESCRIPTION
a
The A/D converter digitizes the analog signal and generate a flow of data.
b
The acquisition engine manages the data acquisition and builds records
of the data. Multi-record recording of data into the DRAM.
c
The transfer of data to the host PC delivers data in buffers for the user.
User schedules the transfer.
d
User's application reads data and headers for further processing and/or
storage.
Figure 25: Acquisition control and data transfer.
7.1 Multi-thread notice
Note that the digitizer does not support multi-threaded applications. In high speed applications, how-
ever, a multi-threading programming style has advantages. In such an application, make sure that only
one thread communicates with the digitizer at a time.
In the example in
Section
cesses data.
Example code available with the digitizer is sometimes written with several threads. Study these exam-
ples carefully to see how multi-threading can be used.
7.2 Acquisition memory
The acquisition memory,
The memory is shared by all activated channels which means that if only one channel is activated, the
entire memory is available for that channel.
The data memory is also shared between data and headers,
about the data record, for example, timestamp and channel number. The headers can be setup in two
different modes:
•
In the normal mode, the headers are activated. This mode is recommended for all standard acqui-
sition modes.
•
In the raw mode, there are no headers and all available memory is used for data. The raw mode is
only recommended for custom firmware built in the ADQ Development Kit.
The memory is organized as a FIFO where it is possible to record data and read out data simultane-
ously. This is called readout-while-recording and is available both in multi-record and streaming mode.
19-2302 A
2020-09-16
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7.6, one thread handles the control of the digitizer. The other thread only pro-
Figure
26, is of size 1 GBytes.
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USER COMMAND
MultiRecordSetup
ArmTrigger
GetDataWHTS
Table
3. A header contains information
ADQ8-4X Manual
19-2302 A 2020-09-16
35(46)
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REF
7.4
7.6
7.1,
7.8,
35(46)
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