I have been working on a OTG device.I have configured my device to function as a host.My peripheral is pen drive(sandisk). I have successfully completed the enumeration.Now that i have started to send the SCSI commands, i have transferred the TEST UNIT READY in a CBW.However when i try to read the CSW from the bulk in endpoint the device is sending the stall .To this i have been issuing the Clear Feature HALT to the Bulk-In endpoint.For the BULK reset the peripheral device have been issuing NAK continuously even after giving a delay of 30 sec.I am not able to read CSW from bulk in endpoint. When should the host start sending the SCSI commands?