Atmel SpaceWire Router SpW-10X User Manual

Page of 155
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)