Atmel SpaceWire Router SpW-10X - Manual (Page 93)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
93
R1
1
2
3
4
5
6
76
Group adaptive routing packet with address 76 arrives at port 1
Ports 4 and 5 are busy routing packet data from ports 2 and 3
Address 76 – Routing table entry
Header Deletion disabled
Port 4
Port 5
Port 6
1 2
R1
1
2
3
4
5
6 76
Routing logic assigns ports 6 to packet at port 1
Figure 8-11 Group adaptive routing when other ports busy
8.3.3.3 Group adaptive routing when ports not ready
A similar arrangement to that of section 8.3.3.2 is shown in Figure 8-12. In this scenario, two of the
output ports which address 76 can use are not ready for use (i.e. the links are not running). The
packet is routed to output port 6 since it is running and not being used to route another packet.
R1
1
2
3
4
5
6
76
Group adaptive routing packet with address 76 arrives at port 1
Ports 4 and 5 are not ready to accept packet data
Address 76 – Routing table entry
Header Deletion disabled
Port 4
Port 5
Port 6
1 2
R1
1
2
3
4
5
6 76
Routing logic assigns ports 6 to packet at port 1
X
X X
X
Figure 8-12 Group adaptive routing when ports not ready
Note: if the Start on Request mode is enabled, the output ports in the group that are not ready will
attempt to make a connection. The packet will be routed to the output port in the group that is ready
first.
8.3.4 Loop-back with Self-Addressing
The Enable Self-Addressing bit in the router control register determines if the router is to support loop-
back connections. Loop-back connections can be useful for debugging or ping operations where a
packet is “bounced” of the router and returned to the source. If the Enable Self-Addressing bit is clear