Power reset question.

[hongpal]

Hello, Nordic!

I'm developing with nrf52840, s340, sdk 15.3.0 in my customboard

Anyway, recently, I have one problem about reset.

My device sometimes has rested and I got power reset reason is 0.

I found that it is because of por or bor.

My device is using high mode and vdd is 1.8 V

I don't know how to solve this problem.

[hongpal]

Yes I can set it to both 2.4 and 2.7.

I have 3 questions.

If I do that,

First, is it more safer than setting 1.8V and

Second, can I aviod bor? 

Finally, Is min voltage section 5.3.8.1 related of input vlotage ?

[Simonr]

Hi

1. That depends on what you mean by "safer". What are you going to use the output voltage for?

2. If you're worried about too low input on your nRF52840 you should set the REGOUT0 to 1.8V to let the nRF52840 "keep" as much power as possible.

3. Yes, section 5.3.8.1 describes the minimum input voltage required to run the nRF52840 in the various operating modes.

Best regards,

Simon

[hongpal]

1. I'm going to use the output voltage for gps, acceleromete, barometer, and gryo.

My board's input voltage is from 3.0V to 4.2V. So it is high to the minimum voltage.

However, my board sometimes reset while working by using gps and communicating phone and I read power reset reason is 0. So it is because of por, bor.

I think it would be bor. Can I prevent the reset if I increase the output voltage from 1.8 to 2.4 or 2.7.

If this doesn't work, what do I do to prevent the reset?

I'm sorry for my English.

[Simonr]

Are you able to power all these peripherals with an output of 1.8V?

The Brown-out resets occur when your input voltage drop below ~3.6V. In order to run the nRF52840 while outputting 1.8V from REGOUT0 you need to be able to power the nRF52840 (1.8V) as well as the output regulator (1.8V). So if possible, you should try to stabilize your voltage source to be more consistent.

Best regards,

Simon

[hongpal]

Yes I am able to power all these peripherals with an output of 1.8V.

Does the Brown-out resets occur when input voltage drop below ~ 1.7V in high voltage mode ?

My battery voltage's range is 3.0 ~ 4.2. Then do I need to cut voltage at 3.6V?