Atmel SpaceWire Router SpW-10X - Manual (Page 80)

Ref.: UoD_SpW-10X_
UserManual
Issue: 3.4
SpW-10X
SpaceWire Router
User Manual Date: 11 th
July 2008
Preliminary
80
8.1.4 Link-Disable
The SpaceWire port can be disabled therefore rendering the link unusable. When a SpaceWire link
which is running is disabled it will disconnect from the far end and refuse connection attempts by the
far end of the link. Caution should be used when using this command for a stand alone router as
disabling all the links will leave the router unusable, except through a reset operation.
WARNING
If the link that is being used to configure the router is disabled then it will not be possible to configure
the router, unless there is another not disabled connection that can be used.
8.1.5 Automatic deactivate driver mode
The SpaceWire port deactivate bit can be set to cause the data and strobe outputs for the link to be
deactivated when the port is inactive. The deactivate mode takes effect dependent on the state of the
Auto-start and the Link-Disabled control bits in the SpaceWire port control register (see section 9.4.3)
and on the Enable Start on Request bit in the router control register (see section 9.5.3).
When Auto-start is enabled and the deactivate bit is set then the data and strobe LVDS drivers are
deactivated until the interface receives a connection attempt by an external SpaceWire device. The
drivers are then enabled until the external device disconnects the link or the SpaceWire link control bit
setup is changed.
When Start on Request is enabled and the deactivate bit is set the LVDS drivers are deactivated until
a request is made from within the router to send data out of the SpaceWire port with deactivated
output drivers i.e. a packet arriving at another port is addressed to be routed out of the SpaceWire port
with deactivated outputs. The drivers are enabled and the SpaceWire port will attempt to make a
connection with the other end of the SpaceWire link.
When Link-disable is asserted and the deactivate bit is set then the data and strobe LVDS drivers are
always deactivated as the link is not in use.
The figure below shows the effect of the deactivate bit when the link setting is Auto-start only.