USB Audio

[lpcware]

Content originally posted in LPCWare by davyarm on Fri Sep 26 11:35:33 MST 2014
Hi,
I am trying to implement USB Audio Input and Output device with Keil LPC4357 EVM using LPOpen 2.x.

I have found AudioInputDevice and AudioOutputDevice examples in old LPOpen 1.3 unfortunately they don't work.

Projects compile fine, device is detected in the system, but no sound is generated or able to record.

Can you please point me to some working examples of USB audio?

Thank you,
David.

[lpcware]

Content originally posted in LPCWare by davyarm on Mon Sep 29 16:45:31 MST 2014
Thank you for the examples.

I studied the second one which is LPCOpen based.
It looks like it's using almost identical AudioOutput.c file which is used in LPCOpen 1_03 lpcusblib_AudioOutputDevice example which unfortunately doesn't work with Keil MCB4357.

I am wondering if LPCOpen 1_03 examples were tested with Keil MCB4357 or only with NGX Explorer board?

It would be great if there are AudioOutputDevice and AudioInputDevice USB examples in LPCOpen 2_xx :)

[lpcware]

Content originally posted in LPCWare by bavarian on Mon Sep 29 03:42:43 MST 2014
There is an example in an older software package which realizes a USB sound card:

http://www.lpcware.com/content/nxpfile/lpc4350apdlzip

Go to the directory  .\lpc43xx_2013-09-04\Examples\SGPIO\SGPIO_I2S_HitexA4\Keil.
This example shows that with the Serial GPIO interface additional I2S interfaces can be emulated.
It is for the Hitex board and it's not based on the LPCOpen project, so in fact it's quite different from what you expect.


There is also an example based on LPCOpen here:

http://www.lpcware.com/content/project/Dual-USB-Host-Device-solution

It's also not for the Keil board, but maybe a little bit easier to port to it than the other project. The source code can be found here:

http://www.lpcware.com/system/files/MicroSD%20card.zip

Hope this helps you,
NXP Support Team.