Atmel SpaceWire Router SpW-10X - Manual (Page 86)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
86
R1 R2 1 2 1 2
Auto-Start default mode
and Start on Request enabled
and Disable on Silence
enable in both routers
R1 R2 1 2 1 2
Packet with
address 2
R1 R2 1 2 1 2
Connection Attempt
Link Started and
Data transfer
R1 R2 1 2 1 2
Data transfer completed
Link Disabled after timeout period
1
2
3
4
Figure 8-5 Disable on Silence mode
The SpaceWire router Disable on Silence mode is used to disable a SpaceWire link when it no longer
has any data to transfer. The Disable on Silence mode is enabled only when the router timeouts are
enabled. The SpaceWire port is disabled if no data or end of packet character has been transmitted
for the timeout period set in the router control register.
The SpaceWire router will only disable a SpaceWire port when the SpaceWire router is the source of
the data transfer. If an external device starts the SpaceWire link or sends packet data to the router
through the link then the link will not be disabled.
8.3 CONTROL LOGIC AND ROUTING
This section describes the operation of the SpaceWire routing logic and how packets are handled for
different modes of operation of the router. The following control bits in the router control register affect
the router operating mode: Timeout Enable, Enable Disable on Silence, Enable Start on Request and
Enable self-addressing.
8.3.1 Packet address error
When a packet with an invalid address, see section 7.4, is received the packet is discarded by the
router. The router is ready to receive the next packet as soon as the invalid address packet has been
spilt.
8.3.2 Arbitration
Arbitration is performed by the SpaceWire router when two or more packets are to be routed through
the same destination port. The router chooses the next packet to be routed to a particular output port