Sony FCB-ER8550 - Page 57

FCB-ER8550/CR8550(GB) D-201-100-12(1)
57
USB commands for firmware update
Basic specifications of commands and response
■ Communication is performed in units of packets.
■ The packet consists of a header (32 bytes) and body
(from 0 byte).
■ Two types of packets in a command and response are
defined as described below.
• Command Data transfer of a host to this unit
• Response Data transfer of this unit to a host
• One response packet is necessarily returned to one
command packet.
* However, there is no response in a specific
command.
■ Byte array is based on a little-endian format.
■ Description of notation
Notation of type
uint: Unsigned integer (Does not depend on the
data length.)
Binary: Binary data string
■ Packet structure
The packet consists of a fixed-length (32-byte) header
and size-variable body.
The maximum packet size is prescribed for each
command or during communication parameter
setting.
Data array Size [Byte] Type
Packet{
Packet Header
32 Packet Header
Body
n Binary
}
■ Packet Header (Common in both a command and
response)
Data array Size [Byte] Type
Packet Header{
BodySize
4 uint
Protocol Version
2 uint
Command ID
2 uint
Response ID
2 uint
Sequence No.
2 uint
reserved
4 uint
reserved
4 uint
reserved
4 uint
reserved
8 uint
}
■ Meaning
Body Size
This is the size of a body following a packet header.
(The size of a packet header is not contained.)
Protocol Version
This is the version of a communication protocol.
Fixed to 0x0100.
(The host sets the protocol version contained in
firmware data.)
Command ID
Command packet: Sets the command to be
executed.
Response packet: The same value as the
corresponding command
packet is set.
Response ID
Command packet: Fixed to 0x0000.
Response packet: ID indicating the processing
result of the corresponding
command
For more details, refer to the specifications for each
command. (See pages 58 to 62.)
Sequence No.
Command packet: Sequence number unique in all
commands
Returned to 1 when an overflow
occurs in the range of 1 to
65536.
Response packet: Returns the sequence number
of the corresponding command
as it is.
An error does not especially
occur even when the value of a
sequence number is skipped.
■ Body
Data used as each command and response parameter
is stored.
The body varies depending on each command and
response.