DAC plugin#

The DAC plugin is used to interface with IIO DACs that implement the IIO buffer mechanism or a DDS mechanism. The plugin consists of an instrument with two data generation modes.

The plugin is compatible with contexts that have at least one IIO device that implements an output IIO buffer or at least one DDS (ALTVOLTAGE) output channel.

Both generation modes feature a few common items in their layout.

  1. Tutorial button

The top left side information button will start a quick tutorial for basic usage of the instrument.

  1. Right side menu

The right side menu is controlled by device or channel buttons. If only one DAC device is detected in the current context, its button will be available at the bottom of the instrument. If more DACs are detected, a left side device list will appear allowing the user to control which is the active and visible one at the moment. All device buttons can control the right side menu and all their IIO attributes are displayed in there.

All the buffer capable channels of an IIO device are also capable to control the right side menu. More on these channel buttons can be found below in the buffer mode section.

Buffer mode#

https://github.com/analogdevicesinc/scopy/blob/doc_resources/resources/dac/dac-buffer.png?raw=true

If the IIO device implements a IIO buffer mechanism, this mode will be active and visible by default. Find all the sections of the instrument described below.

  1. Dac Buffer Settings

Browse and choose a .CSV file containing the channel data you want the DAC to output. Use the “Load” button to check and parse the provided file. The file is interpreted as one column per channel so make sure to structure your file accordingly. The file should not contain any comments or header data as loading will fail.

If loading is successful the “File Size” will be populated with the parsed file size and a new section will appear below.

Note

Only CSV (Comma separated values) accepted for now.

  1. Channels

List of detected IIO channels that are buffer capable. These can be enabled or disabled using their left side check.

  1. Cyclic

Choose whether to push a cyclic IIO buffer or stream non-cyclic buffers. If disabled, a new section containing “Buffer size” and “Kernel buffers” will appear.

By default it is set to true.

  1. File Size

The size of the loaded file. It is populated once loading is successful and can be changed to a lower value, truncating the data loaded from file.

  1. Run Button

Start output generation on the currently enabled channels. If anything is invalid in the setup it will appear in the bottom “Console Log” once the Run Button is pressed.

Some scenarios might be:

  • no channels are enabled

  • there are more enabled channels than data available in the file

  • errors appeared while trying to configure the IIO Buffer

  • the combined enabled channels are not compatible (for I/Q channels)

  1. Data Configuration

This section allows the user to scale the data before output.

  1. Console Log

All errors or status messages are displayed here.

  1. File Configuration

This section is visible only when the buffer is non-cyclic. It contains a control for buffer size and one for kernel buffers. Both are automatically computed and populated when the file size changes. The buffer size can be in range [16, file size] while the kernel buffers can be in range [1, 64].

DDS mode#

https://github.com/analogdevicesinc/scopy/blob/doc_resources/resources/dac/dac-dds.png?raw=true

If the IIO Context contains an IIO Device with DDS capable channels, this mode will become available and will provide an automatically scanned structure for available TX channels with I/Q corresponding channels.

  1. TX header section

This section contains the name of the TX. It can be TX1..TXn or it can be just the index. This is determined based on the detected channels, whether I/Q channels or just simple tx channels are found.

The next area in this section is the DDS MODE selector. The options available are:

  • disabled

  • one tone

  • two tones

  • independent I/Q control

The last item of this section is the Read button which will refresh the values of all attributes below.

  1. Tone area

Based on the selected DDS MODE the layout of this area will change, having visible only the number of tones selected in the previously mentioned selector.

Each tone has three modifiable attributes for “frequency”, “phase” and “scale”.

Note

For scale, “-Inf dB” is equivalent with scale=0 or a disabled channel.

Tutorial#

A tutorial will automatically start first time the tool is open. It can be restarted from tool Preferences.