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Known Issues for LabVIEW DSP Module 2.5

Primary Software: LabVIEW Modules>>DSP Module
Primary Software Version: N/A
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem: What are the known issues for the LabVIEW DSP Module 2.5?

Solution:

Last Updated August 2007

Known Issues
Unsupported Features in DSP Applications
Documentation Issues

Known Issues

The following sections describe known issues at the time of the DSP Module 2.5 release.

  • The Show Implementation feature of the following DSP-specific Express VIs does not find DSP-specific subVIs: Simulate Signal, Sweep Generator, Spectral Measurements, Filter, and DFD Filter.
  • When using a Digital Filter Design Toolkit filter file with the DFD Filter Express VI, the DFD Filter Express VI does not compare the sample rate of the input signal with the sample rate in the filter file. Therefore, the output of the DFD Filter Express VI might be different than what you expect if the two sample rates are not the same value.
  • If LabVIEW is not open and you double-click a custom DSP VI or a DSP VI from the labview\examples directory, LabVIEW cannot find the DSP-specific VIs and opens with a broken Run button. You must open or create a DSP project first and then open the VI in a DSP application instance. Refer to the Creating DSP Projects topic in the LabVIEW Help for more information about creating and using DSP projects.
  • LabVIEW cannot use the external memory on the Spectrum Digital 6416 DSK target. The 6416 DSK has 1 MB of on-chip memory.
  • The Spectrum Digital 6416 DSK uses a fixed-point DSP, but the LabVIEW DSP Module implements floating-point emulation for some algorithms using the Texas Instruments Fast Run-Time Support Library (FastRTS).
  • Larger data types, such as double-precision numerics, might be coerced to a smaller data type, such as a single-precision numeric, without warning or error when you target a DSP depending on the capabilities of the processor.
  • Smaller data types, such as 8-bit integers, might be converted to larger data types, such as 32-bit integers, without warning or error when you target a DSP depending on the capabilities of the processor.
  • When you place an Express VI on a block diagram, the configuration dialog box does not automatically display. Double-click the Express VI on the block diagram to open the configuration dialog box.
  • If you put values in local variables in front panel controls, these values are not updated on the front panel. To see the value, create an indicator on the wire.
  • (SPEEDY-33) If you are using the SPEEDY-33 Robot Daughter Module with the SPEEDY-33 target, you cannot use the DSP LED, DSP LED Bank, DSP Switch, or DSP Switch Bank Elemental I/O Nodes because they share the same hardware resources.
  • (SPEEDY-33) On non-English operating systems, the Windows Found New Hardware Wizard can take 4–5 minutes to locate and install the SPEEDY-33 hardware driver.
  • (Windows Vista) Because the default fonts on Windows Vista are different than the default fonts on previous versions of Windows, you might notice cosmetic issues, such as overlapping or truncated text strings, in VIs and LabVIEW dialog boxes. To correct this problem, change the theme of the operating system to Windows Classic in the Display Properties dialog box, available by selecting StartпControl PanelпDisplay.

Unsupported Features in DSP Applications

  • Clusters and strings
  • Compound arithmetic
  • Conditional Disable and Diagram Disable structures
  • Expandable terminals on array operations and other functions
  • Feedback Nodes with the initialization terminal
  • Formula Node
  • Global variables
  • Mathscript
  • Multidimensional arrays
  • Parallel execution
  • Probes, breakpoints, and execution highlighting
  • Extended precision data representation for the following Express Math & Scientific Constants:
    • Avogadro Constant (1/mol)
    • Elementary Charge (C)
    • Gravitational Constant (N m2/kg2)
    • Molar Gas Constant (J/(mol K))
    • Planck Constant (J/Hz)
    • Rydberg Constant (1/m)
    • Speed Of Light In Vacuum (m/sec)

Documentation Issues

  • Context help does not always update for the new DSP Module Mixed Target controls: Keyboard Input, MIDI Read, Multipurpose Display, Sketchwave, and Receive Character.


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Report Date: 07/11/2007
Last Updated: 08/07/2007
Document ID: 4BA9OOXX

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