That is helpful to know.infiniteimprobability wrote:the app note worked fine on the MFA board (similar processor to the one you are using). Something is different about your setup from the App note .. You shouldn't have to enable mixer actually...
I read the App note again and saw that it assumes a different configuration than I used. In this configuration USB streaming channels from device to host are disabled. I ignored this because I need these channels and forgot about it later.
So I disabled the streaming channels (device to host) and the timing issue is gone.
It also works without enabling the mixer.
But sadly that's not a solution I can use...
I guess the L8 has not enough processing power to get all the features running that I'd like.
So I might switch to a different processor for future designs.
And for the sake of completeness, I don't get the freeze when using PCM 705.6 kHz.
I tried a USB analyzer, but I'm not very familiar with USB.
It seems to me that the data transmission starts (a lot of isoch transfers with ~22576 bytes), but than transfers failed. Don't know why. It seems to restart (select interface, control requests and isoch transfers) and in the end a lot of 'abort pipe' requests with status 'device has gone'.
Thanks a lot for your help.