Atmel SpW-10X Time-Code Processing, Control/Status Registers, SpaceWire Router, User Manual

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

The crossbar switch connects an input port to an output port allowing data to flow from the input port to the output port. Several input ports may be connected simultaneously to several output ports all passing data. Two or more input ports may not be connected to a single output port. The crossbar switch is a “non-blocking” type because the connection of one input port to an output port does not prevent another input port being connected to another output port at the same time. It is possible for all eight input ports to be each connected to an output port so that all input ports and output ports are being used.

3.6 TIME-CODE PROCESSING

An internal time-code register is used in the router to allow the router to be a time-code master or a time-code slave.

In master mode the time-code interface is used to provide a tick-in to the SpaceWire routing causing time-codes to be propagated through the network. Two modes of time master operation are supported, an automatic mode where a time-code is propagated on each external tick-in and a normal mode where the time-code is propagated dependent on the external time-in signal.

In time-code slave mode a valid received time-code, one plus the value of the router time-code register, causes a tick-out to be sent to the SpaceWire links and the external time-code interface. The time-code is propagated to all time-code ports except the port on which the time-code was received. If the time-code received is not one plus the value of the time-code register then the time-code register is updated but the tick-out is not performed. In this way circular network paths do not cause a constant stream of time-codes to be sent in a loop.

3.7 CONTROL/STATUS REGISTERS

The control and status registers in the SpaceWire router provide the means to control the operation of the router, set the router configuration and parameters or monitor the status of the device. The registers are accessed using RMAP [AD2] command packets received by the configuration port.

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