Off Chip Delay (External Port)

We use SigmaStudio extensively with SigmaDSP's but now would like to use the Sharc to allow us to have access to much longer audio delay's. We have a 21369 EZ-Kit and have followed the provided SigmaStudio for Sharc documentation to run simple schematics to transmit test tones off the board via the RCA connectors. The readback functions appear to be working because I can see activity on the level meters and the Get MIPS, GET Version and Read Memory functions work.

After adding the SHARC Audio Toolbox i was trying to work with the Off Chip Delay (External Port). I created a simple schematic (attached), downloaded and I get a large error window (below).

My goal really is to just have a plug in I can use that has a variable max. delay of 1000ms. I'm not familiar with Cross Core but I'm sure I can figure out how to navigate around if that's what I have to do. All other audio functions I need are in the basic sigma studio blocks.

  1. How do I eliminate this error
  2. Can this OffChipDelay plug in be easily modified to increase the delay
  3. Do you have any examples using variable delay (doesn't have to be off chip) I can use for reference
  4. My design will require that I be able to delay up to 16 channels 1000ms each. If I use the EZKIT hardware reference design for my design can these kinds of channel delays be realized? Will I required more off chip memory.

Any help you can provide is much appreciated.

Tst21369_Delay.dspproj.zip
  • 0
    •  Analog Employees 
    on Sep 22, 2014 6:36 AM

    Hi William,

    Please find answers to your questions.

    1. How do I eliminate this error?

    This is a known issue and is documented in the Release Notes. Below text is taken from the Release Notes.

    ====

    SigmaStudio will throw an exception when a Schematic, having a Plug-In built in either of the two VISA/Non-VISA modes, is compiled in the other mode.

    Workaround: Close the exception message box. Change the VISA selection to the supported mode and recompile the schematic.

    ====

    In a SigmaStudio schematic, all the modules should be built in a single mode (either VISA or non-VISA) and the schematic should also be set to the same mode in 'IC Control Window'. The reason for the error is that the 'Off Chip Delay' module supports only VISA mode, but the schematics for ADSP-2136x is in non-VISA mode (there is no VISA support for ADSP-2136x). This exception message will be fixed in upcoming release of SigmaStudio and will be replaced with a meaningful error message. What is your final target? If it is any of the ADSP-214xx processors, the module can be used on the target as such, but if it is ADSP-21369, you will have to rebuild this module in Non-VISA mode with any other changes required to run on ADSP-21369.

    2. Can this OffChipDelay plug in be easily modified to increase the delay?

    Yes. Following changes to be made to support 2000ms delay.

    a. Modify MAX_DELAY_IN_MSEC defined in adi_ext_OffchipDelay.h from 120 to 2000

    b. Open the SSG file, select the Delay NumericUpDown control, modify SetMax in the Properties window from 120 to 2000

    c. Recommended to update 'Name', 'Schematic Cell Name', 'Toolbox Description', 'TreeToolbox Category' so as to distinguish the rebuilt module from the original module and to ensure that both co-exist.

    3. Do you have any examples using variable delay (doesn't have to be off chip) I can use for reference

    No. The other available delay module is the 'Delay' under 'Basic DSP'->'DSP Functions'->'Delay'. Here the maximum delay is limited to 1500 samples. You will have to cascade multiple such delay modules to implemental longer delay. But if your delay length is very large, then it is recommended to use modules which make use of external memory.

    4. My design will require that I be able to delay up to 16 channels 1000ms each. If I use the EZKIT hardware reference design for my design can these kinds of channel delays be realized? Will I required more off chip memory

    16 channel of 1000 ms delay needs around 3000 KBytes of memory. Which EZ-Kit are you targeting?

    Best Regards,

    John

  • Joseph, I am very appreciative for your detailed and timely response.

    Right now we are using a 21369 EZ-Kit. I'm sure we'll be needing another 2 EZ-Kits to help in development. So we aren't necessarily tied do this one. Our interest are:

    1. SigmaStudio compatible
    2. Large channel count
    3. Available EZ-Kit to reference our hardware design to
    4. No BGA

    We will be developing a 32x32 device. If we stay with the 21369 it looks like we need at least 2 Sharc's because 32 channels is max. per Sharc. What do you suggest?

  • Joseph:

    We'll be switching to the ADSP-21489 EZ-KIT so we can easily use this off chip delay.

    95c8eca21dcede023964a21fb5ab5b64.html

  • Hi John,

    As I can learn from your words"This exception message will be fixed in upcoming release of SigmaStudio and will be replaced with a meaningful error message.",does it mean that there will be new version of sigma fro sharc coming?Or it just means the new sigma studio of version 3.11?

    Best Regards,

    Liang.

  • 0
    •  Analog Employees 
    on Sep 24, 2014 5:39 AM

    Hi William,

    Single instance of SigmaStudio for SHARC can handle 32 input and 32 output channels simultaneously.

    Best regards,

    John