Atmel SpaceWire Router SpW-10X User Manual

Ref.:   UoD_SpW-10X_ 

 

Issue:  3.4 

  

 

Date:  11

 

 

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

 

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