Atmel SpW-10X Start on request mode, Disable on Silence mode, SpaceWire Router, User Manual

SpW-10X	Ref.:	UoD_SpW-10X_
SpaceWire Router		UserManual
	Issue:	3.4
User Manual
	Date:	11th July 2008

8.2.1 Start on request mode

The Start on Request mode is enabled by setting the CFG_START_ON_REQ bit in the router control register. The input signal POR_START_ON_REQ_N determines the power on or reset state of the

CFG_START_ON_REQ bit.

When a SpaceWire packet is received which is to be routed out of a SpaceWire port that is not running it would normally be discarded. If the Start on Request mode is enabled instead of discarding the packet the SpaceWire port will attempt to make a connection with the other end of the link. If a connection can be made then the packet is forwarded on towards its destination. This is illustrated in Figure 8-4. This mode allows the SpaceWire ports to be started automatically when there is data to send. This can be used together with output deactivate to save power.

1
				1	R1	2			1	R2	2
							Auto-Start default mode
							and Start on Request
							enabled in both routers
2
				1	R1	2			1	R2	2
		2	2
	Packet with						Connection Attempt
	address 2
3
				1	R1	2			1	R2	2
								2
							Link Started and
							Data Transfer

Figure 8-4 Start on Request mode

8.2.2 Disable on Silence mode

The Disable on Silence mode is enabled by setting the CFG_DISABLE_ON_SILENCE bit in the router control register. The input signal POR_DISABLE_ON_SILENCE_N determines the power on or reset state of the CFG_DISABLE_ON_SILENCE bit.

Figure 8-5 illustrates operation in the Disable on Silence mode.

Preliminary 85