Power reset question.

RE: Power reset question.

Simonr — Fri, 16 Aug 2019 05:59:45 GMT

You might have to find another power source, as it seems like the battery you're using currently may not be powerful enough to run your circuit reliably. You could also use another power source for your peripherals, in order to let the nRF52840 run reliably on the battery you're currently using. I'm sorry, but I don't think there's a software solution to this issue.

Best regards,

Simon

RE: Power reset question.

hongpal — Thu, 15 Aug 2019 12:37:22 GMT

I.m going to check out the voltage on my battery when a Brown-out occurs next day.

Can I prevent the brown-our reset while the voltage is below 3.6V? And
If the brown-our reset occur while the voltage is above 3.6V, What do I do to solve this problem?

RE: Power reset question.

Simonr — Thu, 15 Aug 2019 12:24:45 GMT

Are you able to measure the voltage on your battery when/after a Brown-out occurs, in order to see if this is the culprit? If the brown-out occurs while the voltage is above 3.6V there's some other reason this occurs. Are you able to reliably reproduce this reset somehow?

Best regards,

Simon

RE: Power reset question.

hongpal — Thu, 15 Aug 2019 11:27:08 GMT

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?

RE: Power reset question.

Simonr — Thu, 15 Aug 2019 11:19:46 GMT

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

RE: Power reset question.

hongpal — Thu, 15 Aug 2019 09:49:50 GMT

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.

RE: Power reset question.

Simonr — Thu, 15 Aug 2019 09:24:42 GMT

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

RE: Power reset question.

hongpal — Thu, 15 Aug 2019 08:57:20 GMT

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 ?

RE: Power reset question.

Simonr — Thu, 15 Aug 2019 06:29:17 GMT

The VDD output can be configured in the REGOUT0 register. We do not have a configuration at 2.5V, but you can set it to both 2.4V and 2.7V. Please see the Infocenter for more on this register. Keep in mind that REGOUT0 is in the UICR (flash), so it must be written to flash either via a debugger or programmatically in the same way you write to flash, and won't take effect until you reset the board.

Best regards,

Simon

RE: Power reset question.

hongpal — Wed, 14 Aug 2019 13:17:50 GMT

I mean my device REGOUT0's setting is 1.8 V.

Can I change this setting 2.5V?

I input range is 3.0 ~ 4.2V.

RE: Power reset question.

Simonr — Wed, 14 Aug 2019 13:13:39 GMT

REGOUT0 is the output supply voltage that the nRF52840 can supply an external device with. You will, of course, need more input than your output is set to, so you won't be able to output 3.3V if you only supply the chip with 2.5V for example.

Best regards,

Simon

RE: Power reset question.

hongpal — Wed, 14 Aug 2019 13:04:10 GMT

Thank you your answer!

I found out the section. So I saw min voltage is 2.5V

However, I have one question about this.

I know REGOUT0 is able to adjust vdd level in high voltage mode.

I don't know why is range 1.8 to 3.3.

RE: Power reset question.

Simonr — Wed, 14 Aug 2019 12:06:24 GMT

[quote user=""]My device is using high mode and vdd is 1.8 V[/quote]

If you're using high voltage mode (VDDH) and are powering your device with 1.8V it's not getting enough power to run properly. According to the product specification (section 5.3.8.1 Regulator operating conditions), the high voltage mode requires at least 2.5V.

Best regards,

Simon