Complex Control Commands - Eads Astrium SMCS332SpW User Manual

Interface between three spacewire links

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Reset Link Interface Unit HW

This command performs a hard reset (interrupting all currently running transmissions) of all link interfaces integrated within

one link interface unit.

This command must be enabled.

Read Link Interface Status Register

This commands reads the status register of the link interface and sends the content to the requester within the response

packet of this command.

This command can be executed without being previously enabled.

It depends on the implementation whether the CPU reset and the activate/deactivate signal commands are supported or not. It

is only possible to support all of these commands or none of them. Subsets are not allowed.

13.3.2.2

Complex Control Commands

Currently the following complex commands are foreseen:

enable complex command

read status of complex command enable switch

set link speed to minimum

set link speed to maximum

shut down link operation

restart link operation

Enable Complex Command / Read Status of Complex Command Enable Switch

To enhance security, all safety relevant complex commands must be enabled by a specific command. This command

activates a SW switch which allows the execution of one complex command. If the switch is set or not can be read back by

the respective read status command.

Set Link Speed to Maximum / Set Link Speed to Minimum

These two commands are required since it is assumed that the link interfaces accept in their receiver part transmission speeds

between the minimum and maximum range specified in para. 2 but that their transmission speed do not automatically follow

the speed of the data received from the other node. This has following effect in case of speed increase : although one node is

transmitting at full speed, the link bandwidth is near its minimum value since the FCTs and acknowledgements from the

other node are sent with minimum speed. The node intending to change its transmission speed has to inform the other node

so that their transmission speed can be adapted e.g. by CPU commands forwarded to the link I/F HW.

The actual link speed is indicated in the status register.

This command must be enabled.

Note that the described simple procedure works only for direct connected systems but that systems incorporating a router

require more complicated procedures, e.g by involving the system controller.

Shut Down Link Operation / Restart Link Operation

SMCS332SpW

User Manual

EADS Astrium GmbH, ASE2

Doc No: SMCS_ASTD_UM_100

Issue:

1.4

Updated: 9-Sep-2006

Page:

117 of 131

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