https://devzone.nordicsemi.com/f/nordic-q-a/12541/reset-challenges-nrf-51422Hi, We are developing a product using the nrf 51422 where the power source is a 3 phase generator. We rectify and charge on a supercap where the uProc is being supplied. Now we see if the supercap is completely drained and then slowly chargeden-USTelligent Community 13Wed, 16 Mar 2016 08:42:54 GMThttps://devzone.nordicsemi.com/thread/47586?ContentTypeID=1Wed, 16 Mar 2016 08:42:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e1237da4-e109-4fbd-b54e-ef8abb422dacFlemming Jensen<p>Yes - this is probably what is going on. The cap could be charging very slowly.</p> <p>So I guess we really need an external reset circuit :((</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/47585?ContentTypeID=1Tue, 15 Mar 2016 11:36:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:31db4c14-e9ba-4acb-8396-d1cfdc4db867Ole Bauck<p>How slowly is the capacitor charged?</p> <p>According to the <a href="http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.1.pdf">Product Specification</a> chapter 7, the supply rise time (0V to VDD) needs to be less than 100ms. As it says in the note:</p> <p>&quot;The on-chip power-on reset circuitry may not function properly for rise times outside the specified interval.&quot;</p> <p>Your chip is probably going to an undefined state rather than a reset.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/47584?ContentTypeID=1Tue, 15 Mar 2016 11:11:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b876f1ab-1ed6-40dc-ad0b-8d3c7a5f50f0Flemming Jensen<p>Can I do something in software ?</p> <p>Set a fuse regarding POR / BROWNOUT?</p> <p>Or is this something that needs to be solved maybe using an external capacitor in hardware?</p> <p>Looking forward to hearing from you :))</p><div style="clear:both;"></div>