Code Corrupted after full discharge of batteries, upon reboot. NRF51822 SDK 12.3

[Robin]

Hello Nordic Wizards,

We are in the final throws of a project preparing to go to market.  However we have identified a "strange" problem.

if the batteries driving the board power are allowed to fully discharge, once they start recharging, plugging/unplugging the board from a charger resets the board and may lock the code up in an unknown state.  If the board is reprogrammed, this condition stops, until the next time the battery/board is fully discharged.  Has anyone see these types of problems with this chip, and/or can you point me to a prospective solution.

Thank you kindly

Robin @ TL

[Kenneth]

Please measure the VDD ramp up time when charging to confirm if rise time is within specification.

Regarding the suggestion to try with a 1Mohm resistor on nRESET, it would help if you can do this test, since it would help understand if missing power on reset is part of the problem or if it is something else.

Robin said:

If batt/board are dead, can gpios be high?

I don't know your design, I am asking if you have secondary power or sensors in your design that may feed a gpio with power even if VDD is discharged.

Also test suggestions by David.

[Robin]

Hello again Kenneth,

1.) Please let me know where I can find this VDD ramp up spec.

2.) If I am not using pin as nReset, why would this help?

3.) No secondary power in system.

4.) I am not sure how to implement flash content test around a battery discharge, as the system is unusable until reprogrammed.  Any guidance here is greatly appreciated.

5.) What software features must I check to be sure the chip powers down safely with battery discharge?

Thank you again,

Robin@ TL 

*** New Info:

1.) I have completed the VDD ramp test.  It is up to full voltatge within 300uS, as I suspected. 

2.) I also tested quick discharge of battery (~20mS).  Symptoms remain the same.  Once discharged, the code does not start when a charge source is initiated.  Removing the charge source and resetting board power allows the code to start, adding the charge source back freezes the code.  This continues until the chip is reprogrammed.

3.) After adding the pulldown to the nRESET pin, there is a change is symptoms.  The chip will not reboot and run even after a board power reset.  It only runs after a reprogram.

Stand by for flash content testing...

[Robin]

Hello David,

I just downloaded the latest command line tools.  There is no nrfjprog in the mix only the latest segger tools. What next?

Thx

Robin @ TL 

[daviddedwin]

If you downloaded, unzipped  and installed the nrf command line tools, you should have the nrfjprog installed.
Make sure that you run the "nRF-Command-Line-Tools_10_13_0_Installer_64.exe" inside the zip file.(this file is for Win64).

Once installed you can run the nrfjprog within a Windows command window (cmd.exe)

[Robin]

Hello David,

I did run the installer.  When I try to run nrfjprog from a cmd window, Windows claims it is not a valid command.  Where is it installed?  Ill run it from that folder.

Tjx agn

R @ TL