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Use HID functions of PCM2707?

Hanns
Expert 1005 points

Hi all!

We've now got a fully functional pcm2707 application and a couple of questions regarding the pcm2707 and its HID functions. The HID endpoints #0 and #5 are briefly covered on page 18 of the d/s.

1. Volume adjustment made on PC do not effect the digital I2S audio output of the pcm2707 but only that of the headphone output and this is quite understandable.

However, I would like for the pcm2707 to inform a uC over SPI when the PC reports audio adjustments.

Is there any way to accomplish this?

2. Accoding to the d/s, the device implements an extra HID class USB endpoint #5 but I can't find any actual info as of what functions this HID device supports. Maybe this is in fact the endpoint used by the pcm2707 to issue HID reports to host.

If not, where can I obtain this information?

Cheers!

  • 0
    TI__Genius 16270 points

    Hanns,

    EP#5 supports Play/Pause (0xCD), Stop (0xB7), Previous (0xB6), Next (0xB5).  These are done via SPI writes, and once the command is sent to the PCM2707 then a status will be reported to the host.  Regarding PC reporting, when SPI volume adjustments are made they are known by the SPI sender, so is there a different setup in question? 

  • 0 in reply to Patrick Galvin
    Expert 1005 points

    Yes, then it is like I assumed, ie that ep#5 is the one used for the chip to send input reports regarding playback transport, volume etc to the host. The uC has a IR remote receiver and uses spi to trigger input reports to be sent to usb host by the chip. This part is very clear to us.

    Instead, the question was if it is possible to catch the events of volume adjustments being made on the host pc. That is, when the user drags the volume slider of the OS, we would like the uC to be made aware of this. Is this possible somehow?