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?
bulk in often lose packet
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Guest
Re: bulk in often lose 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)
a) Check ACK by Youself if you need it
q)How to send empty bulk in packet?
a) Just send ACK!(status)
Re: bulk in often lose packet
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.
