Atmel SpaceWire Router SpW-10X - Manual (Page 100)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
100
R1
1
2
3
4
5
6
(a)
4 5
R2
1 4
2
3
5
6
4 4
Figure 8-25 Source Node Stalled: Watchdog Mode (a)
b) The packet from routing switch R1 port 3 is routed towards its destination but during packet
transfer the source node stalls and does not supply any more data or the end of packet.
R1
1
2
3
4
5
6
(b)
R2
1 4
2
3
5
6
4 4
Figure 8-26 Source Node Stalled: Watchdog Mode (b)
c) The packet is blocked and the packet waiting at routing switch R1 port 2 cannot be routed.
The watchdog timers in routing switches R1 and R2 detect the packet has become blocked
and spills data from the input port and appends an error end of packet to the output port. This
causes the network path from routing switch R1 port 4 to routing switch R2 port 1 to be
cleared and the next packet can be routed.
R1
1
2
3
4
5
6
(c)
R2
1 4
2
3
5
6
4 4
EEP
Figure 8-27 Source Node Stalled: Watchdog Mode (c)
d) The packet waiting at R1 port 2 can now be routed.
R1
1
2
3
4
5
6
(d)
R2
1 4
2
3
5
6
Figure 8-28 Source Node Stalled: Watchdog Mode (d)