ok.i understand...now i'm trying to transfer a character e.g "A" through USB and then send it to SBUF0 &SBUF1.From the example given by Cypress.com,there's bulkloop example which is transfer data in EP2FIFOBUF to EP6FIFOBUF...i modified the code to send "A" which is i fix "A" in EP2FIFOBUF and then send it to SBUF0.using the simulator,yes it occured but when i used with the board,nothing appeared.can you help me?