Atmel SpaceWire Router SpW-10X - Manual (Page 72)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
72
Command
Byte
The command byte indicates a write single address, with verification and
acknowledgement packet. 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.
0,4,8,12
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
Write
Address
The extended write address is not used in the SpaceWire router and is
always expected to be zero.
1
Write
Address
The write address identifies the register to write the RMAP data. The valid
write addresses are defined in section 9.
4
Data
Length
The data length of a write single address command is expected to be 4 bytes,
to write to a 32 bit register location
3
Header
CRC
The header CRC is the eight bit CRC code used to detect errors in the
command packet. The CRC code is checked before the command is
executed
1
Data The 32 bit data value to write to the SpaceWire router register. 4
Data CRC The data CRC used to detect errors in the data part of the command packet. 1