Atmel SpaceWire Router SpW-10X - Manual (Page 73)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
73
In Figure 7-11 the format of the reply to a write command is illustrated. The first byte sent by the
SpaceWire router configuration logic is the port address followed by the destination logical address.
Fields which are depicted in bold text are expected values. Fields which are shaded are optional. Note
that the reply is always sent out of the same port as the command was received on. The Source Path
Address should not include the output port of the router being commanded as the reply will be
automatically sent out of the same port that the command arrived on. See section 7.6.8.
Source Path Address
Source Logical Address
Protocol Identifier
01h
Packet Type, Command,
Source Path Addr Len
Status
Destination Logical Address
FEh
Transaction Identifier (MS) Transaction Identifier (LS) Reply CRC
Source Path Address Source Path Address
EOP
First byte transmitted
Last byte transmitted
1 1 0 0 1 0
Bits in Packet Type / Command / Source Path Address Length Byte
MSB
Packet Type Command
Source Path
Address Length
Source Path
Address Length
LSB
Source Path Address Length
Figure 7-11 Write Single Address Reply Packet
Table 7-16 Write Single Address Reply Packet Fields
Field Description Bytes
Source
Path
Address
Optional source path addresses specified in the command packet. If no source
path addresses are specified then the first byte will be the source logical
address.
0-12
Source
Logical
Address
The source logical address specified in the command packet. If source path
addresses are not used then the source logical address is the address of the
return packet.
1
Protocol
Identifier
The RMAP protocol identifier value 01h. 1
Command
Byte
Write single address reply command byte. The packet type bits in the command
byte indicate this packet is a reply packet.
1
Status The command status is returned in this field. The command status can be
command successful or an RMAP error code as defined in section 7.6.6.
1
Destination
logical
The destination logical address is set to the default value FEh as the
SpaceWire router does not have a logical address.
1