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<?xml-stylesheet type="text/xsl" href="https://devzone.nordicsemi.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>BLE disconnection issue</title><link>https://devzone.nordicsemi.com/f/nordic-q-a/55824/ble-disconnection-issue</link><description>Hi 
 I face ble disconnection issue. 
 we use external crystal 32.768khz. However, when I check it , the load cap is wrong. It should be about 9pF but it is 1pf. 
 The frequency tolerance is about 350ppm. 
 Unfortunately, when we change it into internal</description><dc:language>en-US</dc:language><generator>Telligent Community 13</generator><lastBuildDate>Thu, 19 Dec 2019 13:14:49 GMT</lastBuildDate><atom:link rel="self" type="application/rss+xml" href="https://devzone.nordicsemi.com/f/nordic-q-a/55824/ble-disconnection-issue" /><item><title>RE: BLE disconnection issue</title><link>https://devzone.nordicsemi.com/thread/226380?ContentTypeID=1</link><pubDate>Thu, 19 Dec 2019 13:14:49 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:39e39355-d86d-40c5-98fd-eef180774e0c</guid><dc:creator>Simonr</dc:creator><description>&lt;p&gt;Hi&lt;/p&gt;
&lt;p&gt;I think you&amp;#39;ll need at least 12pF caps for your external crystal here. Can you upload the crystal datasheet so I can take a look? Please note that when using the LFRC all these defines in sdk_config.h must be set to the following values:&lt;/p&gt;
&lt;p&gt;&lt;pre class="ui-code" data-mode="text"&gt;// &amp;lt;/h&amp;gt; 
//==========================================================

// &amp;lt;h&amp;gt; Clock - SoftDevice clock configuration

//==========================================================
// &amp;lt;o&amp;gt; NRF_SDH_CLOCK_LF_SRC  - SoftDevice clock source.
 
// &amp;lt;0=&amp;gt; NRF_CLOCK_LF_SRC_RC 
// &amp;lt;1=&amp;gt; NRF_CLOCK_LF_SRC_XTAL 
// &amp;lt;2=&amp;gt; NRF_CLOCK_LF_SRC_SYNTH 

#ifndef NRF_SDH_CLOCK_LF_SRC
#define NRF_SDH_CLOCK_LF_SRC 0
#endif

// &amp;lt;o&amp;gt; NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval. 
#ifndef NRF_SDH_CLOCK_LF_RC_CTIV
#define NRF_SDH_CLOCK_LF_RC_CTIV 16
#endif

// &amp;lt;o&amp;gt; NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature. 
// &amp;lt;i&amp;gt; How often (in number of calibration intervals) the RC oscillator shall be calibrated
// &amp;lt;i&amp;gt;  if the temperature has not changed.

#ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV
#define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2
#endif

// &amp;lt;o&amp;gt; NRF_SDH_CLOCK_LF_ACCURACY  - External clock accuracy used in the LL to compute timing.
 
// &amp;lt;0=&amp;gt; NRF_CLOCK_LF_ACCURACY_250_PPM 
// &amp;lt;1=&amp;gt; NRF_CLOCK_LF_ACCURACY_500_PPM 
// &amp;lt;2=&amp;gt; NRF_CLOCK_LF_ACCURACY_150_PPM 
// &amp;lt;3=&amp;gt; NRF_CLOCK_LF_ACCURACY_100_PPM 
// &amp;lt;4=&amp;gt; NRF_CLOCK_LF_ACCURACY_75_PPM 
// &amp;lt;5=&amp;gt; NRF_CLOCK_LF_ACCURACY_50_PPM 
// &amp;lt;6=&amp;gt; NRF_CLOCK_LF_ACCURACY_30_PPM 
// &amp;lt;7=&amp;gt; NRF_CLOCK_LF_ACCURACY_20_PPM 
// &amp;lt;8=&amp;gt; NRF_CLOCK_LF_ACCURACY_10_PPM 
// &amp;lt;9=&amp;gt; NRF_CLOCK_LF_ACCURACY_5_PPM 
// &amp;lt;10=&amp;gt; NRF_CLOCK_LF_ACCURACY_2_PPM 
// &amp;lt;11=&amp;gt; NRF_CLOCK_LF_ACCURACY_1_PPM 

#ifndef NRF_SDH_CLOCK_LF_ACCURACY
#define NRF_SDH_CLOCK_LF_ACCURACY 1
#endif&lt;/pre&gt;&lt;/p&gt;
&lt;p&gt;Best regards,&lt;/p&gt;
&lt;p&gt;Simon&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>