Atmel SpW-10X user manual Msb

SpW-10X	Ref.:	UoD_SpW-10X_
SpaceWire Router		UserManual
	Issue:	3.4
User Manual
	Date:	11th July 2008

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.

	First byte transmitted
	Source Path Address	Source Path Address	Source Path Address
Source Logical Address	Protocol Identifier	Packet Type, Command,	Status
	01h	Source Path Addr Len
Destination Logical Address	Transaction Identifier (MS)	Transaction Identifier (LS)	Reply CRC
FEh
EOP			Last byte transmitted

Bits in Packet Type / Command / Source Path Address Length Byte

MSB

0 0 1 1 1 0

Packet Type Command

LSB

Source Path Source Path Address Length Address Length

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	Optional source path addresses specified in the command packet. If no source	0-12
Path	path addresses are specified then the first byte will be the source logical
Address	address.
Source	The source logical address specified in the command packet. If source path	1
Logical	addresses are not used then the source logical address is the address of the
Address	return packet.
Protocol	The RMAP protocol identifier value 01h.	1
Identifier
Command	Write single address reply command byte. The packet type bits in the command	1
Byte	byte indicate this packet is a reply packet.
Status	The command status is returned in this field. The command status can be	1
	command successful or an RMAP error code as defined in section 7.6.6.
Destination	The destination logical address is set to the default value FEh as the	1
logical	SpaceWire router does not have a logical address.
	Preliminary	73