http://forums.leaflabs.com/topic.php?id=10176 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:20:48 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=10176#post-22296 Wed, 06 Feb 2013 17:26:52 +0000 gbulmer 22296@http://forums.leaflabs.com/ <p>stafil - What time reference are you using to measure the output of PC13?<br /> How are you calculating the deviation?<br /> Is it plausible that some of the error comes from the way the deviation is being measured? </p> http://forums.leaflabs.com/topic.php?id=10176#post-22294 Wed, 06 Feb 2013 14:12:45 +0000 stafil 22294@http://forums.leaflabs.com/ <p>I used olimexino stm32 and tamper pin(PC13)(LSE/64) frequency is 512.2Hz it is too large for calibration rtc. In AN2821:</p> <p>01032 /* Calulate Deviation in ppm using the formula :<br /> 01033 Deviation in ppm = (Deviation from 511.968/511.968)*1 million*/<br /> 01034 if(f32_Frequency &gt; 511.968)<br /> 01035 {<br /> 01036 f32_Deviation=((f32_Frequency-511.968)/511.968)*1000000;<br /> 01037 }<br /> 01038 else<br /> 01039 {<br /> 01040 f32_Deviation=((511.968-f32_Frequency)/511.968)*1000000;<br /> 01041 }<br /> 01042 DeviationInteger = (uint16_t)f32_Deviation;<br /> 01043<br /> 01044 if(f32_Deviation &gt;= (DeviationInteger + 0.5))<br /> 01045 {<br /> 01046 DeviationInteger = ((uint16_t)f32_Deviation)+1;<br /> 01047 }</p> <p>my f32_Frequency = 512.2Hz and DeviationInteger = 638 is too large (0-121) is possible.</p> <p>Where is the problem? Pls help me. </p> http://forums.leaflabs.com/topic.php?id=10176#post-22147 Mon, 28 Jan 2013 11:41:53 +0000 gbulmer 22147@http://forums.leaflabs.com/ <p>stafil - there are several threads on using the RTC, for example: <a href="http://forums.leaflabs.com/topic.php?id=1058" rel="nofollow">http://forums.leaflabs.com/topic.php?id=1058</a> </p> http://forums.leaflabs.com/topic.php?id=10176#post-22140 Mon, 28 Jan 2013 05:39:42 +0000 stafil 22140@http://forums.leaflabs.com/ <p>How I calibrate RTC using 32.768KHz crystal? Pls help me. I used mapleRTC<br /> RTClock rt(RTCSEL_LSE, 0x7fff + 14); </p> <p>how set prescaler?</p> <p>Thx </p>