This version is outdated by a newer approved version.DiffThis version (11 Oct 2012 17:48) was approved by Brett Gildersleeve.The Previously approved version (11 Oct 2012 17:47) is available.Diff

This is an old revision of the document!

DSP Readback

Click here to return to the Basic DSP page

The DSP Readback block lets you read values back from the DSP at any point in your schematic design.

The number displayed onscreen is the data value sent back from the DSP considering all the blocks to the left of the Readback block. Every time you click Read, this value will be updated with the latest from the DSP. By displaying the output value from any block, in any format desired, Readback is used chiefly for debugging, and probably will prove very handy.

Values can be read back in either hex or decimal. For the latter, you must specify what format you want the number to be displayed in. The default for 1st generation SigmaDSPs (including AD1940, AD1941, ADAU1701, ADAU1702, ADAU1401) is 5.19: 5 bits for the integer, 19 for the decimal. Any changes to this format will shift the decimal value of the number displayed.

Newer SigmaDSPs like the ADAU1761, ADAU1781, and ADAU1442 are able to read back in full 28-bit (5.23) accuracy.

See here for more information about the numeric formats used in SigmaDSP.

For a sample design using this block, see the Basic DSP example.

For some examples of using this cell to check the peak or RMS level of a signal, please see this EngineerZone forum FAQ: Monitoring average and instantaneous signal levels

Configuring Continuous Readback

The DSP Readback cell can be configured to read back from the target DSP repeatedly at regular intervals. To enable this mode, right-click the cell and select Start Continuous Read.

You can also click the small circle in the cell to enable or disable Continuous Read mode. When the circle is blue, Continuous Read mode is active. When the circle is orange, Continuous Read mode is inactive.

When Continuous Read mode is active, you can change the update rate by right-clicking on the cell and selecting from a list of options. Selecting a slower update rate will allow you to have more readback cells operating at the same time, and will lower the chances of a buffer underrun error on the USB interface.

resources/tools-software/sigmastudio/toolbox/basicdsp/dspreadback.1349970492.txt.gz · Last modified: 11 Oct 2012 17:48 by Brett Gildersleeve