Lpc2000

At 09:13 PM 6/15/05 +0000, Josh Ferguson wrote:
>--- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@a...>
>wrote:
> > At 07:13 PM 6/15/05 +0000, Josh Ferguson wrote:
> > >So far I've successfully loaded and run the two example (blinky and
> > >Hello) programs specifically written for the lpc22xx board.  I've
>now
> > >moved onto the CAN examples.  The one I'm specifically trying to
>get
> > >to work is CANBlinky.  It compiles and I can put it on the board
> > >without problems and it appears to be running (the LED is blinking)
> > >but I'm getting nothing from CAN2 which is supposed to be
> > >transmitting A/D data.  Are there any gotchas when I try to run
>these
> > >CAN examples on the 2294 board?
> >
> >
> > First question.  What else is hooked up to your CAN bus?
> >
> > Robert
> >
>
>I have a PEAK CAN to USB connector connected to my laptop and I'm
>running the software that came with that connector that simply
>listens to the CAN and shows the packets or can send packets manually
>back to the device.

OK, I'm going to assume the example SW works.  I don't know either the 
board or the Peak convertor but I've a few more general things to check.

         - termination.  Both ends of your cable need to be 
terminated.  BTW what are you using for cable?  It is possible even likely 
that neither the board or the Peak convertor have on-board termination 
since the usual use of CAN is on a bus and only the ends of the bus should 
be terminated.
         - baud rate.  Make sure both sides are using the same baud 
rate.  Unfortunately that's not as straight forward a question as it sounds 
since the rate is determined by the interaction of a set of parameters.
         - I expect that the Peak SW will include a facility to show the 
error counters and bus state.  It would be a good idea to take a look at 
them although I expect at this point all they will tell you is that you are 
in buss off state due to accumulated errors.  Speaking of which, you must 
reset both ends when retrying, otherwise you will be stuck in bus-off and 
won't end up testing the changes.
         - Another simple check make sure you haven't got your wires crossed.
         - Also check to see if the Peak convertor has an isolated 
interface.  It may need power coming in from the bus side.

Robert

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