Atmel SpaceWire Router SpW-10X - Manual (Page 78)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
78
Figure 7-12 and Figure 7-13 illustrate how source path addresses are returned in relation to the RMAP
packet description.
00 00 04 02
Dest Logical Protocol ID Command Dest Key
Source Logical Trans ID(1) Trans ID(0) Address(4)
Figure 7-12 Source Path Address field decoding
Source Logical Protocol ID Command Status
02 04
Local Source
Path Address
Figure 7-13 Source Path Addresses in Reply Packet
7.6.10 Command Packet Fill Bytes
The Configuration port accepts packets which are addressed to port 0. In the RMAP command the
next byte after the destination address 0 is the destination logical address byte (which in the router is
expected to be the default 254 value). The format is shown in Figure 7-14.
Path
Address
0
Dest
Logical
Address
254
Protocol ID
1
RMAP Header
Figure 7-14 Normal Configuration Packet Header Structure
To allow source nodes which have a 16, 24 or 32 bit access port then the configuration port accepts
up to three null bytes at the start of the packet. The null bytes must be zero otherwise they will be
treated as the destination logical address and an invalid destination logical address shall be recorded
if the byte is not 254. The header with fill bytes is shown in the Figure 7-15.
Fill Byte
0
Dest
Logical
Address
254
Protocol ID
1
RMAP Header
Fill Byte
0
Fill Byte
0
Path
Address
0
Figure 7-15 Fill Bytes Configuration Header Structure
Note that the command packet fill bytes feature is specific to the SpW-10X router and is not part of the
RMAP standard.