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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>One of two nRF52840 USB sticks DOA</title><link>https://devzone.nordicsemi.com/f/nordic-q-a/49106/one-of-two-nrf52840-usb-sticks-doa</link><description>I have just purchased 2 pcs. nRF52840 - one of them works fine - the other one reports this when i run dmesg on my linux (tested on 2 different systems) &amp;quot;Cannot enable. Maybe the USB cable is bad?&amp;quot;, then it reports &amp;quot;attempt power cycle&amp;quot; and repeats the</description><dc:language>en-US</dc:language><generator>Telligent Community 13</generator><lastBuildDate>Mon, 01 Jul 2019 19:43:01 GMT</lastBuildDate><atom:link rel="self" type="application/rss+xml" href="https://devzone.nordicsemi.com/f/nordic-q-a/49106/one-of-two-nrf52840-usb-sticks-doa" /><item><title>RE: One of two nRF52840 USB sticks DOA</title><link>https://devzone.nordicsemi.com/thread/195759?ContentTypeID=1</link><pubDate>Mon, 01 Jul 2019 19:43:01 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:14cdf048-069a-4853-bb44-0eea28cc7d01</guid><dc:creator>Keld_Norman</dc:creator><description>&lt;p&gt;great guide - i will find the voltmeter and measure - thnx&amp;nbsp;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: One of two nRF52840 USB sticks DOA</title><link>https://devzone.nordicsemi.com/thread/195573?ContentTypeID=1</link><pubDate>Mon, 01 Jul 2019 09:37:03 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:ec3a9544-9b42-4e3f-a023-18b371087690</guid><dc:creator>Andreas</dc:creator><description>&lt;p&gt;Hi,&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;No worries, noone is born an expert with any of our products.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;The dongle should be shipped with a bootloader that allows programming over USB, it might be something to do with that. Could you see what the voltage is on VDD_nRF (test point on the bottom)? This should be 3V. This not being 3V is itself not a problem, but indication that something is up with the bootloader.&lt;/p&gt;
&lt;p&gt;Also, if you are able, what is the voltage across C20? This should be 3.3V if the USB part of the IC is powered and running correctly.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;You might find this blog post handy:&amp;nbsp;&lt;a href="https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial"&gt;https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/nrf52840-dongle-programming-tutorial&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;It is probably of little use to solve this problem,but might shed some light on the nRF52840 dongle in general. There is also a description of how to flash the bootloader if that is corrupted.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Best regards,&lt;/p&gt;
&lt;p&gt;Andreas&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: One of two nRF52840 USB sticks DOA</title><link>https://devzone.nordicsemi.com/thread/195467?ContentTypeID=1</link><pubDate>Sat, 29 Jun 2019 22:23:45 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:9931feff-b1a3-4d62-b0c1-ebf922fe5108</guid><dc:creator>Keld_Norman</dc:creator><description>&lt;p&gt;yes - tested in a windows10, a fitlet2 running debian and another linux running kali - same message. The first stick worked fine but when i got to the other one i never got it to identify it self so i could upload the f irmware to it. I thought the firmware needed to be loaded before it could identify it self to the system - like a low level driver function ? I have never worked with this nRF52840 before so excuse me my missing knowledge about how it works.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: One of two nRF52840 USB sticks DOA</title><link>https://devzone.nordicsemi.com/thread/195400?ContentTypeID=1</link><pubDate>Fri, 28 Jun 2019 14:19:49 GMT</pubDate><guid isPermaLink="false">137ad170-7792-4731-bb38-c0d22fbe4515:c974023e-992e-46b9-a8cf-d171d81238fe</guid><dc:creator>Andreas</dc:creator><description>&lt;p&gt;Hi,&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Strange that one works and one does not. Have you tried it on a different PC and/or operating system?&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;
&lt;p&gt;Best regards,&lt;/p&gt;
&lt;p&gt;Andreas&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>