Objective Development Forums

I will implements mass storage class on v-usb, mass stroage class must use bulk in,bulk out. when read a sector,need 64 packets(8 bytes per packet),often lose packet.
I look usb 1.1 spec, when bulk in transfer,host will send ack.
1.whether or not v-usb check ack?
2.How to send empty bulk in packet?

q)whether or not v-usb check ack?
a) Check ACK by Youself if you need it
q)How to send empty bulk in packet?
a) Just send ACK!(status)

Bulk endpoints with V-USB are really tricky. The USB polling consumes most if not all of the CPU time. If the interrupt service routine comes too late, you lose a packet. Since V-USB does not implement error handling (no CRC checks etc), you may lose packets.