Re: Strange timer LED behavior

["Bollinger, Seth" <Seth.Bollinger@digi.com>]

> 
>> Is there a way to avoid this?  Even if we write the on value twice,
>> it will flash for 500ms at least once…
> 
> There should be. Can you simply write new values to on and off,
> without writing zeros there?

In this case we’re switching from on:86400, off:0 -> on:0, off:86400.  We write off first, then on using fwrite() to a file.  From the trace, it looks like on is always stored first.  So, the first store is on:0, off:0 for a brief period (enough to trigger the default), and then off is stored.  We’re already trying to not have them not both be zero at the same time.  I tried putting fflush() between them, but that didn’t help.  I suppose we could try to sleep some period of time, but this seems bad as well.  Maybe write and read to verify the value is correctly stored?

> 
> If not, can you use 1 instead of zero?

I have not measured the flash, but if on is 1ms, it’s on for a pretty good chunk time (our LED controller is over i2c).  It’s a very noticeable flash.

> 
>> 
>> I tried setting the trigger to none, but of course this disabled the display settings and setting the trigger to timer ends up flashing at the default rate, which is also what we don’t want.
>> 
> 
> If there's no reasonable value to change the frequency, we'll need to
> fix that.

I think if we could control the delays with trigger set to none, then we could set the delays and enable the timer trigger for a no glitch operation.  I suppose if there was a timer-off trigger, that would work as well, but seems kind of silly.


Seth