XScopes
User’s Manual
DS-XScopes-3.5
– December, 2014
Page | 29
5.2
Custom AWG Waveform
You can define your own waveforms for the AWG. On the Waveform Generator tab, click “Open CSV” and select your
CSV file, then click “Save as Custom”, the waveform will be permanently saved in the device’s EEPROM memory. When
creating a CSV file, the range of the data must be [-127, 127], and there should be only 256 numbers.
5.3
Saving Waveforms and Screenshots
On the Options tab there are buttons to save and load waveforms,
as well as saving screenshots of the graph area in PNG format. When
saving a waveform or screenshot, the program will ask for a destination
folder only once, and then use this folder for subsequent files. When
opening a waveform, the “Clear” button must be pressed to continue
normal operation.
The Record button allows saving waveforms continuously. The Play button is used to playback a recording.
6.
The XScope can communicate to external devices thru the USB or the external port. Each interface can access the Xscope’s
main settings. Follow the protocols to make your own applications, or to make devices that attach to the XScope.
6.1
Interface settings
The settings for communicating with the serial port are shown in Table 9. If using the USB interface, you can use
WinUSB or LibUSB libraries. The USB device’s endpoints have a size of 64 bytes. The device uses BULK IN transfers on
endpoint 1 for transferring data (770 bytes in SCOPE mode: CH1, CH2, CHD, FRAME and INDEX; 1289 bytes in SNIFFER
mode), BULK OUT transfers on endpoint 1 to write to the AWG RAM buffer (256 bytes), and CONTROL READ transfers on
endpoint 0 for changing and reading settings. The FRAME and INDEX are variables used to check the flow of the data. They
are also needed if you want to implement the ROLL mode.
The
FRAME
will increase whenever a full buffer has been acquired. For the fast sampling rates, this will occur all the time.
Ideally, when you read data, the FRAME will increment by 1 every time. If you see that the FRAME has incremented by
more than 1, then you are not reading data fast enough and missing frames of data. In the slow sampling rates, since you
can read faster than the acquisition, the FRAME will help you determine if you are reading from the same frame.
The
INDEX
is not used in the fast sampling rates. For the slow sampling rates, it indicates the current position in the buffer.
For example, if you set the Xprotolab at 1S/div, you will see on the display that the samples start filling the screen from left
to right. The index represents this position. So for the slow sampling rates, the FRAME and INDEX can help you determine
if you need to erase the screen, and you are able to show more data on the screen (similar to the Xprotolab screen).
6.2
Control Data
All XScope’s settings are stored in 44 bytes, table 10 shows these variables, table 11 describes the bitfield variables.
Figure 55: File operations
Summary of Contents for XScopes
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