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Make sure that you have called
EtherSpaceLink_set_active_link()
and are thus communicating
with the expected SpaceWire port.
Don’t forget to call
EtherSpaceLink_flush ( DSI_unit )
when you wish transmissions to take place.
17.5
My API program works for a while and then hangs...
Are you still successfully writing to the EtherSpaceLink unit SpaceWire port(s), or has all of the buffering in the
TCP/IP connection and the EtherSpaceLink unit filled up because the device under test is not responding?
Are you still properly attempting to read from the EtherSpaceLink unit?
Did your API program call one of the status routines listed in section 17.5.3, “Asynchronous Issues during Status
Polling”, while data was being transmitted from the EtherSpaceLink unit? If so, some of that data might have
been lost while the status routine was awaiting its status information. Re-read that section for some suggestions,
or re-cast your program as in the API example, “An Advanced API Example”.
Has your device-under-test livelocked or deadlocked?
In a multithreaded API application, the synchronisation of information between the SpaceWire receive thread and
the SpaceWire transmit thread might have been programmed incorrectly, and thus has livelocked or deadlocked.
Turn on logging, using
EtherSpaceLink_set_log_file()
, and see what was transmitted last in each
direction on each SpaceWire link.
If you have a 4Links Multi-link SpaceWire Recorder, now would be a good time to look more closely at the traffic
passing through your SpaceWire network.
Have you filled up the disk on your host computer?
17.6
Ethernet Performance in large networks
The TCP/IP packet re-transmission timeout is set at a fixed period of 1 second; it should be statistically derived
from the performance of the network. Congestion control of the Ethernet packet transmit rate is not
implemented. This is not an issue in local area networks where errors are (very) rare and packets are
acknowledged in much less than one second; problems may arise with large non-local networks.
17.7
Waveform capture offset from event
An event flag in the transmit stream triggers a waveform capture before it gets to the connector pins; waveforms
so captured have their time reference slightly offset from the external appearance of the event.
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