Source and capture functionality allows you to insert data or extract data from a pattern burst. Use source or capture functionality when the data you need to use is site-specific or only determined at run time. For example, if there is a digital protocol that's associated with passing data to or from the DUT, the pattern defines the protocol. The protocol might be clocking or chip selects. You can source the data from source memory or capture the data into capture memory.

The source and the capture functionality is useful in the following cases:

  • When the data you need to use can be separate from the pattern. For example, tests that require site-specific data, data stimulus to a DAC, or data response from an ADC.
  • If the data that needs to be written is only determined at run time, such as register reads or writes.

The functionality prevents the need to compile new patterns in the middle of a test execution or to have all possible response patterns pre-loaded. Each digital pattern instrument includes source and capture functionality for up to eight sites. You can send source waveforms and receive capture waveforms through any of the pins on the digital pattern instrument. Refer to the PXIe-6570 Specifications for more information about the number of channels you can connect for each digital pattern instrument.

Note Make sure the average data rate for source or capture data doesn't exceed the digital pattern instrument's maximum rate. Visit ni.com/info and enter the Info Code DigitalSourceCapture to access Calculating Source and Capture Bandwidth for Digital Pattern Instruments for more information.
Note Configure source and capture functionality on each synchronized digital pattern instrument to use it across multiple instruments with NI-TClk..

Refer to the Digital Pattern User Manual for more information about NI-Digital Pattern Driver source and capture API, source and capture configuration in Digital Pattern Editor, and source and capture opcodes.

Sourcing Waveforms

Configuring Source Waveforms

Use the source waveform configuration document in the Digital Pattern Editor or the NI-Digital Pattern Driver source API to configure source waveforms.

You can configure source waveforms for serial or parallel use:

  • In serial waveform type, each vector that contains a source opcode serially shifts 1 bit on the pin using the drive from source pin state (D) to indicate what value to drive. The data width of the serial source sample is set up at configuration, and after an appropriate number of bits have been shifted, the source engine moves on to the next sample.
  • In parallel waveform type, the entire waveform sample is sourced on all specified pins in parallel for each vector that contains a source opcode. Use the drive from source pin state (D) for each pin on each such vector that corresponds to the pins to source.
Note Ensure that the total average data rate for the source or capture data falls within the maximum source or capture rate for the digital pattern instrument. Visit ni.com/info and enter the Info Code DigitalSourceCapture to access Calculating Source and Capture Bandwidth for Digital Pattern Instruments for more information.

When configuring serial and parallel source waveforms, you can specify one of the following data mapping options:

  • Site Unique—Sources unique waveform data to each site.
  • Broadcast—Writes the same waveform data to all sites if multiple sites are configured in the pin map.

    • Sending Source Waveforms

    You can send source waveforms at run time using opcodes in the pattern file. Use the source_start and source opcodes to send waveform data when you burst the pattern. Use the source_d_replace opcode to change the behavior of the source data.

    Source Considerations

    • You can send multiple source waveforms with the same configuration in a single pattern burst.
    • You can load up to 512 source waveforms on the instrument at a time.
    • The total number of pins supported by source functionality is 32.

    Refer to the PXIe-6570 Specifications for more information about source capacity.

    Capturing Waveforms

    Learn how to configure and receive capture waveforms using serial or parallel methods on digital pattern instruments. Understand the use of opcodes and capture considerations to optimize waveform data capture.

    Configuring Waveforms

    You can configure capture functionality for serial or parallel use.

    To configure capture waveforms, use the configuration document for the capture waveform in the Digital Pattern Editor or the NI-Digital Pattern Driver capture API.

    You can configure capture waveforms for serial or parallel use.

    • In serial waveform type, each vector that contains a capture opcode serially shifts 1 bit on pins using the pin state V. You set up the data width of the serial capture sample during configuration. After an appropriate number of bits shift, the capture engine moves on to the next sample.
    • In parallel waveform type, the entire waveform sample is captured on all specified pins in parallel for each vector that contains a capture opcode. Use the pin state V for each pin on each vector that corresponds to the pins for which you want to capture waveform samples.
    Note Capture memory stores a single bit per channel per capture cycle. The memory stores A 1 for any line where Vout > Voh and Vout > Vol. Otherwise, the memory stores a 0. Capture memory shows M pin states as 0.
    Note Keep the average data rate for source or capture data below the digital pattern instrument's maximum rate. Visit ni.com/info and enter the Info Code DigitalSourceCapture to access Calculating Source and Capture Bandwidth for Digital Pattern Instruments for more information.

    Receiving Capture Waveforms

    You can receive capture waveform data at run time using opcodes in the pattern file. Use the capture_start, capture, and capture_stop opcodes to store values when you burst a pattern.

    Capture Considerations

    • You can receive multiple capture waveforms with the same configuration in a single pattern burst.
    • You can use up to 512 capture waveforms on the digital pattern instrument at a time.
    • The total number of pins supported by capture functionality is 32.

    Refer to PXIe-6570 Specifications for more information about the number of samples you can capture for all patterns in a burst operation.