If flag B is stuck at low, it means that the Data has not been read by the Host PC. One common reason why this occurs often could be that FX3 has gone into low power mode.
The PC might force FX3 to go to low power mode because of which data in FX3's DMA will be left unread.
Can you please call CyU3PUsbLPMDisable () API after the CyU3PConnectState API and check?
Hi,Thanks for your reply,I will test that this week.