Atmel SpaceWire Router SpW-10X - Manual (Page 91)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
91
R1
2
5
1
3 52
4
52
R1
2
5
1
3 52
4
Two packets waiting to use port 5
(Previous port which accessed port 5 = 4)
Packet from port 1 is selected
HIGH priority packet arrives at port 4
R1
2
5
1
3
4
Packet from port 1 completes
HIGH priority packet from port 4 is selected
Port number 3 waits
Packet arrives on port 1
R1
2
5
1
3
4
Packet from port 4 completes
Previous low priotity packet which accessed port 5 = 1
Therefore port 3 is selected
Packet on port 1 waits
1 2
3 4
Addresses
80 – HIGH Priority
52 – LOW Priority
80
52
52
R1
2
5
1
3
4
Packet from port 3 completes
Packet waiting on port 1 is selected
5
R1
2
5
1
3
4
Packet from port 1 completes
6
52
Figure 8-9 Arbitration of two packets with different priority (2)