Please enable JavaScript.
Coggle requires JavaScript to display documents.
USB - Coggle Diagram
USB
-
data is transmitted as packets , marked with SOP and EOP sequences on both ends. The payload of the packet is framed with PID and CRC. There are 4 bits to the PID, however to insure it is received correctly, the 4 bits are complemented and repeated, making an 8 bit PID in total.
Data packets, obviously, carry data, with Data0 and Data1 used alternatively just as a method of error checking (otherwise identical), CRC16
-
-
-
-
Handshake packets are sent in the end of the transaction and reflect its status through the PIDs. No other payload and hence no CRC is envisaged. No handschakes in isochronous mode.
-
STALL (PID 0b1110)
An error happened, the device puts the corresponding endpoint on hold.
-
-
-
Token packets indicate the start of a transaction. The payload consists only from ADDR and ENDP (in the case of SOF Token only one field even, Frame No.). Since the payload size is minimal, CRC5 is used.
-
-
-
-
-
-
-