I'm working on an audio sensor interface to to smart phones to allow the array of phone app "test equipment" to be used. My initial thought was to use a cheap USB dongle for input (because phones are less and less likely to have an audio jack and to prevent damage to a phone), but these dongles only have a mono mic input; line inputs on small (& cheap ) dongles don't seem to exist.
So, typical of scope creep, adding an audio codec seems like a better route to take. The Texas Instruments PCM2903C seems like a good option. Stereo line inputs and not too many external parts required. Does anybody have experience with these chips or similar chips (basically a sound card chip that handles the USB connection)?
The PCM2903C is self-powered. For my test version, I had hoped to power a board from USB, but the '2309C requires power before making the USB connection. Other functions of my board will ultimately require battery power, but I was hoping to avoid that for my test board. The PCM2902C is bus powered which would be ideal for the test version, but its (fixed?) USB descriptor only requests 100mA.
One other question for anybody familiar with these chips - a number of profiles are supported. Stereo or mono, sample rate, etc., but no methods of selecting these is specified. I assume this is set on the USB host device?
I appreciate any suggestions, but I'm looking for a self-contained device to go from audio input --> USB interface.
So, typical of scope creep, adding an audio codec seems like a better route to take. The Texas Instruments PCM2903C seems like a good option. Stereo line inputs and not too many external parts required. Does anybody have experience with these chips or similar chips (basically a sound card chip that handles the USB connection)?
The PCM2903C is self-powered. For my test version, I had hoped to power a board from USB, but the '2309C requires power before making the USB connection. Other functions of my board will ultimately require battery power, but I was hoping to avoid that for my test board. The PCM2902C is bus powered which would be ideal for the test version, but its (fixed?) USB descriptor only requests 100mA.
One other question for anybody familiar with these chips - a number of profiles are supported. Stereo or mono, sample rate, etc., but no methods of selecting these is specified. I assume this is set on the USB host device?
I appreciate any suggestions, but I'm looking for a self-contained device to go from audio input --> USB interface.