Run CAN 8473 on with full bus

[anAlias]

Using Borland C++ and a CAN USB-8473, I'm trying to watch a full CAN bus and put the data into an STL map.

The CAN/PC can't keep up.  I have the 8473 configured as a Frame

I have observed that the Config option NC_ATTR_READ_Q_LEN does not appear to work.  I have set the value to 1000000, which is about 3X more then the amount of data that I sent, but I still get buffer overflows.  I get buffer overflows after about 10000 messages, which should be 100X before I run out of buffer.

[DirkW]

Hi,

yes you are right the queue numbers are no used by USB CAN. What error number do you get for your overflow? Do you use the read mult function?

DirkW

[anAlias]

I get the following response ncRead::NI-CAN: (Hex 0xBFF62125 NI-CAN copies received CAN frames from the card to a large kernel-level queue.  There is one queue for each interface (port).  If your application does not read fast enough to empty this queue over time, the newest frames are lost.  Solutions:  Call Read more frequently (such as by reducing user-interface code).  ...

Is there a hard set size for the queue?  I've been using read (not mult).  

[Burban]

To monitor a full bus with the USB-8473, use ncReadMult and disable analysis such as graphing during the network monitoring.

[anAlias]

I also needed to not use ncWaitForState, and don't poll ncReadMult in a while loop waiting for a zero size.  Just check it once every 10 msec or so, looking for 150 messages.