question about the power consumption of nRF52832 in BT connected and advertising mode

[PYC]

the power consumption is about 6.12mW in BT connected, and consumption is about 7.75mW in advertising mode.

is it normal or has possibility to reduce it to extend the battery life?

thanks in advance.

[awneil]

It will depend very much on your settings - connection interval, advertising interval, etc ...

you can explore it with the online Power Profiler:

https://devzone.nordicsemi.com/nordic/power/w/opp

[PYC]

https://devzone.nordicsemi.com/nordic/power/w/opp/2/online-power-profiler-for-ble

excuse me, here is result by our setting, may you review it to see there is any setitng could improve the power consumption?

Thanks.

[Stian Røed Hafskjold]

You need an external 32MHz crystal to run the radio peripheral.

[PYC]

use external 32MHz crystal could be lower power consumption than use internal, is it correct?thanks.

[awneil]

it's not an option - as Stian Røed Hafskjold said, you need it for the radio to work.

[Stian Røed Hafskjold]

The internal and external clocks are used in two different ways, and not really comparable. The internal clock is started whenever it is needed by the peripherals automatically, e.g. the CPU. It has a very short startup time and cannot be controlled by the application. The external crystal has to be started manually, and will consume current after being started even though it's not actually being used. The startup time is a lot longer, and you will typically not use this unless you need the increased accuracy provided by the crystal, which in fact the radio does. If you just look at the run current for the CPU when running from the external crystal versus the internal clock, it's almost the same.

[PYC]

The I2C specification allows a line capacitance of 400 pF at most.
• The nRF52832 internal pullup has a fixed value of typ. 13 kOhm, see RPU in the GPIO chapter

->i checked the spec of nrf52832, saw the information as above. 52832 has internal pullup 13kohm, if program that to be I2C, do i need to do external pullup? 

->if it still needs pullup resistor on i2c, what value of pullup is preferred?

thanks.

[awneil]

What does this have to do with the topic of this thread - "power consumption of nRF52832" ?

[PYC]

excuse me, we are debugging the power consumption in our application, the value of ours is higher than evaluation board, just to see is there any chance to save more power consumption. 

[Stian Røed Hafskjold]

You typically don't need external pullups on the I2C, if you use the internal 13k pullups

[awneil]

Stian Røed Hafskjold said:

You typically don't need external pullups on the I2C, if you use the internal 13k pullups

13K would typically be a bit high for a 3V I2C bus, surely?

PYC said:

if it still needs pullup resistor on i2c

I2C always needs pullup resistors - that is fundamental to the bus operation.

The way to check if your value is OK is to look at the lines with an oscilloscope:

https://www.avrfreaks.net/comment/3074021#comment-3074021 - see the diagram & follow the link

Remember that the pullups will only ever draw current when the bus is in the low state; ie, during '0' bits of a bus communication. The bus idles high - so the pullups cause no current when idle.

[Stian Røed Hafskjold]

Thanks for clarifying awneil