http://forums.leaflabs.com/topic.php?id=124 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:17:39 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=124#post-965 Thu, 02 Sep 2010 21:30:59 +0000 bnewbold 965@http://forums.leaflabs.com/ <p>Fixed and commited: <a href="http://github.com/leaflabs/libmaple/commit/1c6f9a9b5e9f1896a6c3d1faa895af74b6c7e3e1" rel="nofollow">http://github.com/leaflabs/libmaple/commit/1c6f9a9b5e9f1896a6c3d1faa895af74b6c7e3e1</a> </p> http://forums.leaflabs.com/topic.php?id=124#post-771 Thu, 19 Aug 2010 11:09:47 +0000 bnewbold 771@http://forums.leaflabs.com/ <p>I think you're right CarlO, I just have a sloppy off-by-one error there; I will update the library with bounds checking and test the output for accuracy. </p> http://forums.leaflabs.com/topic.php?id=124#post-761 Wed, 18 Aug 2010 15:08:47 +0000 poslathian 761@http://forums.leaflabs.com/ <p>Interesting find, nice catch! Let me think about it some more. The way you have it seems to make it possible to set overflow to -1...</p> <p>I think perhaps the source of your off by 1 error was from doing an integer divide on 71 by 2, which will probably end up as a shift right operation, which is 35 - not 36. </p> http://forums.leaflabs.com/topic.php?id=124#post-757 Wed, 18 Aug 2010 11:26:56 +0000 CarlO 757@http://forums.leaflabs.com/ <p>Update:</p> <p>I modified my local copy of HardwareTimer.cpp as follows.</p> <p>Line 84 was:</p> <p> setOverflow((microseconds*72)/ps);</p> <p>Line 84 modified to:</p> <p> setOverflow(((microseconds*72)/ps)-1);</p> <p>This seems to fix the timer accuracy.</p> <p>Does anyone see any problems with fixing the code this way?</p> <p>Carl </p> http://forums.leaflabs.com/topic.php?id=124#post-755 Tue, 17 Aug 2010 22:09:49 +0000 CarlO 755@http://forums.leaflabs.com/ <p>Hey LeafLabs folks,</p> <p>Thanks for a great product.</p> <p>I may have found a bug in the code for the Timers.</p> <p>The following code produces a nearly perfect square wave at 999.986KHz, well within the tolerance for the crystal.</p> <p> pinMode(9,PWM);<br /> Timer4.setPrescaleFactor(1);<br /> Timer4.setOverflow(71);<br /> pwmWrite(9,36);</p> <p>The next piece of code, however, returns an Overflow value of 72 and produces a nearly square wave at 986.098KHz</p> <p> pinMode(9,PWM);<br /> int Overflow = Timer4.setPeriod(1);<br /> pwmWrite(9,Overflow/2);</p> <p>I have similar results using a period of 2 etc. The frequency is off by a proportion equal to the overflow value off by 1. Are you accounting for the timer count starting at zero?</p> <p>Thanks for your help,</p> <p>Carl </p>