Testing USB communications between the PC and SigmaDSP

Discussion created by BrettG on Mar 22, 2011

When using an evaluation board for the first time, it's a good idea to check the communications between the PC and SigmaDSP to make sure everything is working properly. The easiest way to do this is to create a small program that runs inside the DSP that does not make use of the audio inputs or outputs on the board. In its most basic form, a value can be loaded into memory via the control port and then read back via the control port.


If the read/write operation is successful, it informs us that:

  • The SigmaDSP is being clocked properly and the PLL is locked.
  • The DSP core is running.
  • The download from SigmaStudio via the USB interface completed successfully.
  • The I2C/SPI control port is able to access memory for reading and writing.


In this example, I'll use an ADAU1761.


First, set up the board's hardware as shown in the QuickStart guide that is included in the evaluation kit. Usually this involves setting switches or jumpers.


Then, create a project file in SigmaStudio and follow the QuickStart guide to set up the hardware communications interface.


Now, in the project file, create two cells: a DC Source and a DSP Readback cell.

ScreenHunter_01 Mar. 22 10.34.jpg


ScreenHunter_02 Mar. 22 10.35.jpg


Connect them like this:


ScreenHunter_03 Mar. 22 10.35.jpg




ScreenHunter_04 Mar. 22 10.35.jpg


If there's something wrong with the master clock, PLL, evaluation board setup, or communication interface, you will see the following error:


ScreenHunter_05 Mar. 22 10.35.jpg


If you don't see that error, you should be able to click the Read button and see 1.00000 in the display.


ScreenHunter_06 Mar. 22 10.37.jpg


You should also be able to type a new value into the DC Source cell (anything between -16 and 15.99999) and then click the Read button to see it again in the DSP Readback cell.


ScreenHunter_07 Mar. 22 10.37.jpg


If you are able to complete these steps, you have verified that the USB communications are functioning correctly.