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Multiple SHARC DSP with USBi


We  are curently using the ADSP-SC589 SHARC DSP in combination with SigmaStudio. We have it connected via a USBi interface which uses SPI to communicate and evrything works great.

For our new design we would actually want to use 2 of these DSP's with sigma studio. According to the documentation of the USBi ( the following is possible:

The USBi can support up to two identical devices on the same SPI latch if the SPI address pins of the target devices are independently set to two different addresses, matching the addresses in the drop-down box in the Hardware Configuration tab of SigmaStudio.

So as i understand it, it should be possible to connect 2 SPI slaves (the DSP's) to the USBi with both using the same CS signal, thus requiring no changes to the USBi connector. I am assuming the addressing then happens on a SPI protocol level? How exactly is the address configured on the DSP? Is this configured in the function call "adi_ss_connection_Init" in the firmware running on the DSP?

According to the documentation it is also possible to address different devices using the additional cs pins on the USBi. However, this requires additional wires to be soldered to the USBi and devboard and i would like to avoid this and prefer the other solution.

Best regards,


  • Hello Robrecht,

    I moved this post over to the SigmaStudio for SHARC space which is where you will get better support. You had posted it on the SigmaDSP space. 

    On the SigmaDSP the part has address pins and has dedicated SPI and I2C hardware. I do not know the SC589 very well and I think it might be a software implementation. So I would think you can assign an address. Someone in this space can help you with that. In the SigmaDSP world we set the pins to different addresses then they can share the same SPI latch. If you do go the route of using different latches then take a peak at the EVAL-ADAU1452RevB user guide. In there I show how to add the additional latch and a trick I used with a header pin and jumper cable. 


    Dave T