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usb audio asynchronous prepare data out

Question asked by on Jun 30, 2016
Latest reply on Jul 1, 2016 by Chinzei.Tsuneo
hi guys,

I am doing usb audio asynch with stm32f072,

my problem is

USBD_LL_PrepareReceive(pdev, AUDIO_OUT_EP, &PlaybackBuf[buftoogle],  AUDIO_MAX_PACKET_SIZE);

My audio is 48Khz 24bit which will generate 288bytes so I set my endpoint max buffer size to 300 for 12 extra bytes
So when I tried to set it to 300 and my feedback value is exactly 48<<14, it will simply count until 300 not stop at 288 as I need. As result my audio mess up.

So how to received different size of data as host will adjust data length according to feedback that we send? do we need to change the size dynamically ? if yes when ?