Atmel SpaceWire Router SpW-10X - Manual (Page 67)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
67
Table 7-12 Read-Modify-Write Command Packet Fields
Packet
Field
Description Bytes
Config Port
Address
The configuration port address field routes the packet to the configuration
port of the router. The configuration port address is always present when
configuring the SpaceWire Router.
1
Destination
Logical
Address
The destination logical address is not used in the SpaceWire Router. The
SpaceWire router accepts packets which have the default destination logical
address of 254h (FEh).
1
Protocol
Identifier
The RMAP protocol identifier is 01h. 1
Command
Byte
The command byte indicates a read-modify-write command. The Source path
address length fields are set to the number of source path addresses
required as defined in section 7.6.9.
1
Destination
Key
The destination key identifier must match the contents of the destination key
register, see section 9.5.10.
1
Source
Path
Address
The source path address field is used to add source path addresses to the
head of the reply packet. The expected number of source path addresses is
specified in the command byte. See section 7.6.9 for source path address
decoding.
0,4,8,16
Source
Logical
Address
The source logical address should be set to the logical address of the node
which sent the command.
1
Transaction
Identifier
The transaction identifier identifies the command packet and reply packet
with a unique number.
2
Extended
RMW
Address
The extended read address is not used in the SpaceWire router and shall
always be set to zero.
1
RMW
Address
The read-modify-write address identifies the SpaceWire router register
address to modify. Valid RMW addresses are defined in section 9.
4
Data + The data length of the read-modify-write command is 8, 4 bytes for data and 3