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What Timed-loop Priorities Are Valid For Blackfin?

Primary Software: LabVIEW Modules>>Embedded Module for Blackfin Processors
Primary Software Version: 1.0
Primary Software Fixed Version: 2.5
Secondary Software: N/A

Problem:
I have a VI created with the LabVIEW Embedded Module for Blackfin Processors with a timed loop and other code.  I set the period of the timed loop to 1ms, but the actual update rate seems to be around 50ms. How do I correct this?

Solution:
The priority of the timed loop needs to be higher than the thread that created the timed loop.
The valid range for timed loop priorities on the Blackfin is 26 to 30 (inclusive), which are the valid thread priorities available in the Blackfin's VDK operating system. 

In versions of the LabVIEW Embedded Module for Blackfin Processors prior to 2.5, LabVIEW sets the priority of the timed loop to 100 in the timed loop dialog. A priority of 100 is invalid for the Visual DSP++ Kernel, so it gets set to the default priority 26, which is the same as the priority of the main block diagram thread.    The default timed loop priority in version 2.5 of the module is 26. Changing the timed loop priority to 27 in the dialog will yield the expected update rate since this will instruct the operating system to give more processing cycles to the timed loop.

Related Links:
KnowledgeBase 3WAD2DKN: LabVIEW Embedded Module for Blackfin Processors 1.0 Documentation Resources

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Report Date: 10/10/2006
Last Updated: 11/16/2007
Document ID: 429BJ1NE

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