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ECSS errors: ESC-ESC, ESC-EOP, ESC-EEP, Timeout, Parity error.
Users should note that a time-tag report is ten bytes long, and if it is enabled on every byte of a packet results in
eleven times as much traffic as for the packet alone; this can soon saturate the Ethernet connection and should
be used with caution. Time-tagging the first data byte and the end of packet marker gives useful information with
a much lower overhead and is recommended for normal use.
DSI Version 1.0 introduced an optional delta time-tag which is used when the interval between timetags is short
(<
∼
6.5μs), reducing the Ethernet size of a time-tag from ten to four bytes and thus reducing the traffic generated
by time-tags.
Flow-control and error tokens are not normally visible. They will not be time-tagged unless they have been made
visible - see the Event Reporting option (section 8, “Option ER - Event / Error Reporting”).
We suggest that familiarisation with this feature is gained with the
SpWIO
program before using it from a C
program.
10
Option EI – Event/Error Injection
This option allows errors to be introduced into a data stream in a controlled manner by extending the character
set to include bytes representing:
Parity error;
ESC-EOP;
ESC-EEP;
ESC-ESC;
Idle periods that may be set to exceed the SpaceWire disconnect timeout period.
Link behaviour may be changed in ways that produce both ECSS-conformant behaviour and non-ECSS (i.e.
erroneous) behaviour:
At link start, the number of flow-control tokens sent may be set between 0 and 15 (only values from 1 to
7 conform to the ECSS standard);
Automatic sending of flow-control tokens may be suppressed, leaving the user to send FCTs or not, as
required - this allows links to be tested with a shortage of FCTs and with an excess;
The link may be set so that data is transmitted regardless of whether there is sufficient flow credit.
ECSS errors normally cause the link to reset and restart. It is possible to set the links in a DSI to continue operating
by ignoring some or all of these errors:
Parity error;
ESC-EOP;
ESC-EEP;
ESC-ESC;
Timeout.
Содержание Diagnostic SpaceWire Interface
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