nRF51822 not reset

[wan]

We are develop one product, it is power by four AA battery. It works fine. but now I found a problem. when I power off and then power on again, sometime it can not be reset. I monitor the VCC voltage of chip, found when I power off, and the VCC voltage will drop down, when it drop down to about 0.4V and power it on again, the chip will can not be reset. how to resolve this problem?

[Kenneth]

Hi, we need more information that would allow us to find exact cause, please create a case on My Page and add the following details:

• Schematic and layout.
• A description of test setup.
• Frequency of occurrence and build code.
• Analog capture of VDD, nRESET, DEC1 and DEC2.

[bin simon]

hello,wan. Have you resolved the above problem? If so, could you tell me how you did it? I've been facing the same problem. I hope you will be able to provide the information.

[Swain1]

Hi Wan, did you find a fix for this issue? we are having similar issue where it does not reset properly each time when the VCC does not go right off. If you have any information that would be great!

[Jon (jono)]

Edited: 0.4v was on an IO-pin, not VCC.

We have reproduced this error, one io pin remains at approx 0.4v over night. On the morning when powering back up to 3v3 @ 4ms the chip does not boot.

Software ligths led and delays first thing -> not a sw issue.

Repeated powercycles chip does not reset! During these cycles there are some residual potential on VCC in the range 0.4..0.1V

Has happened at least 4 times and on different units. Chip rev: N51822QFACA11544GA.

[Jon (jono)]

Nordic: Any news on this one? We're still experiencing this problem once in a while, especially a backup capacitor keeping the RTC active may keep this issue active for a very long while.