SH7216 Datasheet, PDF (24/32 Pages) Renesas Technology Corp – USB Mass Storage Class

SH7216 Group
USB Function Module: USB Mass Storage Class
5.7 Processing If an Error Occurs
The errors that may occur during a USB Mass Storage Class (Bulk-Only Transport) transmission between the host PC
and function, and how the function operates when an error occurs are described below.
The Bulk-Only Transport standard defines the following two types of errors:
⎯ Invalid CBW
⎯ Operation expected by the host PC and operation planned by the function (operation specified by the SCSI
command) do not match (10 cases)
The Bulk-Only Transport standard does not cover any other states.
There are 13 states for data transfer between the host PC and a function as shown in tables 18 and 19. Cases (1), (6) and
(12) are normal transport states.
Table 18 Data Transport States between Host PC and Function
What the
function plans
No data transport
Data send to host PC
Data reception from host PC
What the Host PC Expects
No Data
Transport
Data Reception
from Function
(1) Hn = Dn
(4) Hi > Dn
(2) Hn < Di
(5) Hi > Di
(6) Hi = Di
(7) Hi < Di
(3) Hn < Do
(8) Hi < > Do
Data Send
to Function
(9) Ho > Dn
(10) Ho < > Di
(11) Ho > Do
(12) Ho = Do
(13) Ho < Do
Table 19 Explanation of Data Transport States between Host PC and Function
Case No.
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
Relation between Host PC and Function
The host PC expects no data transport and the function plans no data transport.
The host PC expects no data transport but the function plans to send data to the host PC.
The host PC expects no data transport but the function plans to receive data from the host PC.
The host PC expects to receive data from the function but the function plans no data transport
to the host PC.
The amount of data the function sends to the host PC is less than the amount of data the host
PC expected to receive from the function.
The amount of data the function sends to the host PC is equal to the amount of data the host
PC expected to receive from the function.
The amount of data the function sends to the host PC is greater than the amount of data the
host PC expected to receive from the function.
The host PC expects to receive data from the function but the function plans to receive data
from the host PC.
The host PC expects to send data to the function but the function plans no data transport to the
host PC.
The host PC expects to send data to the function but the function plans to send data to the host
PC.
The amount of data the function receives from the host PC is less than the amount of data the
host PC expected to send to the function.
The amount of data the function receives from the host PC is equal to the amount of data the
host PC expected to the function.
The amount of data the function receives from the host PC is greater than the amount of data
the host PC expected to send to the function.
REJ06B0897-0100/Rev.1.00
July 2009
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