Atmel SpW-10X user manual Functional Overview, SpaceWire Router, Preliminary

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

3. FUNCTIONAL OVERVIEW

A SpaceWire routing switch comprises a number of SpaceWire ports and a routing matrix. The routing matrix enables packets arriving at one SpaceWire port to be transferred to and sent out of another port on the routing switch. A SpaceWire routing switch is thus able to connect together many SpaceWire nodes, providing a means of routing packets between the nodes connected to it.

The SpW-10X SpaceWire router comprises the following functional logic blocks:

•Eight SpaceWire bi-directional serial ports.

•Two external parallel input/output ports each comprising an input FIFO and an output FIFO.

•A crossbar switch connecting any input port to any output port.

•An internal configuration port accessible via the crossbar switch from the external parallel input/output port or the SpaceWire input/output ports.

•A routing table accessible via the configuration port which holds the logical address to output port mapping.

•Control logic to control the operation of the switch, performing arbitration and group adaptive routing.

•Control registers than can be written and read by the configuration port and which hold control information e.g. link operating speed.

•An external time-code interface comprising tick_in, tick_out and current tick count value.

•Internal status/error registers accessible via the configuration port.

•Watchdog timers on all ports.

•Internal status/error registers accessible via the configuration port using the RMAP protocol [2].

•External status/error signals.

A block diagram of the routing switch is given in Figure 3-1.

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