> -----Original Message----- > From: ecos-discuss-ow...@ecos.sourceware.org [mailto:ecos-discuss- > ow...@ecos.sourceware.org] On Behalf Of Nick Garnett > Sent: Friday, May 27, 2016 11:27 AM > To: ecos-discuss@ecos.sourceware.org > Subject: Re: [ECOS] cyg_flag_timed_wait doesn't seem to work as > expected > > > > On 27/05/16 14:30, Michael W. Ellis wrote: > > I'm running an old version of eCos (2.0.98) from eCosCentric and I'm > > attempting to use cyg_flag_timed_wait to periodically update a > display > > (see code, below). My event flag variable g_flags is initialized > > elsewhere before this thread is created. Other threads access the > > same event flag but use their own bits within the flag. > > > > My problem is with the timed wait behavior of the event flag. At > > startup I see an initial wait of 30 seconds before the first display > > update occurs, but the update occurs continually after the initial > > timeout. The local variable flags always reads 0, indicating timeout > > has occurred. My understanding is that calling cyg_flag_timed_wait > at > > the top of the loop restarts the timer, but this does not seem to be > > the case. What am I missing here? Is there something I must do to > > clear the timeout event? > > > > The problem is your use of 3000 for the timeout. In eCos, timeouts give > the wakeup time, not the duration. So, the first call waits until tick > 3000, but the rest return immediately since it is now past 3000. > > The solution is to use cyg_current_time()+3000 in the timeout argument. > > -- > Nick Garnett Kernel Architect > eCosCentric Limited http://www.eCosCentric.com The eCos experts > Barnwell House, Barnwell Drive, Cambridge, UK. +44 1223 245571 > Registered in England and Wales: Reg No: 4422071 >
This makes perfect sense now. I made this change and everything is working as I expect. Thanks, Michael -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
