TimeStamp in nRF52832

[Sunil vignesh]

Hi, 

I am using nRF52832, SDK16.0

with SES

Is that nRF52832 have able to send timestamp through BLE.  is that hardware able to calculate timestamp  

will it act as REAL TIME CLOCK 

[Einar Thorsrud]

Hi,

You can use the RTC peripheral in the nRF to keep time, but remember that the RTC will be reset when the chip is reset for any reason. Also, there is no HW for mapping the RTC ticks to time and date, so you need to keep the calendar in SW. If this is not acceptable, then you need to use an external dedicated RTC chip.

[Sunil vignesh]

My case is . I need to read the sensor data and through value to the mobile app. device has to connect the mobile phone daily. and mobile app it send data to server. there it will have date time respective sensor data .

but if the device not connected to mobile for two days . the sensor data will be stored in external EEPROM / FLASH but i need to send timestamp . to match the database.

Can you give solution for that

[Einar Thorsrud]

I see. If you are happy with the risk of getting an incorrect timestamp in case of a reset, then you can use the internal RTC (perhaps using the app timer library and a repeated timer to update your timekeeping SW). We do not have any official examples for that, but you can refer to nrf-calendar-example.

[Sunil vignesh]

Here SW, are mentioning flash storage ?

internal RTC is a counter right? . i have to count the time until reset or power off. When it again power up the data will be lost right?

i will refer that example

[Einar Thorsrud]

Hi,

Sunil vignesh said:

internal RTC is a counter right?

Yes, the RTC is a counter that can count 32.768 kHz clock cycles, which may or may not be divided by a Prescaler. (So the accuracy of the RTC is given by the accuracy of your 32 kHz clock source.)

Sunil vignesh said:

i have to count the time until reset or power off. When it again power up the data will be lost right?

In principle yes, though you could use a method such as suggested by hmolesworth, which seems like a very good suggestion.

[Sunil vignesh]

will timer / counter work in sleep mode?

[Einar Thorsrud]

The RTC will work in normal low power (system ON) sleep mode, yes. It is always used when you use BLE for instance, in order to wake up at connection events, advertising events etc. The current consumption is system ON low power mode is ~2-3 uA, which is not very much.

It will not run in system off mode, though, but most applications never use system off. In system off the IC is almost entirely powered off, and can only wake up on GPIO, LPCOMP or NFC.

[Sunil vignesh]

will you suggest any external ic for Timestamp.

how nrf_calender works.

how the time and date will taken

[Einar Thorsrud]

Hi,

Sunil vignesh said:

will you suggest any external ic for Timestamp.

I do not have any suggestions for that. It is not directly related to the nRF, but perhaps some other members on this forum has some suggestions?

Sunil vignesh said:

how nrf_calender works.

nrf_calendar uses the RTC to generate ticks and the time.h library to map this to actual calendar time and date. You can refer to the source code for details.

Sunil vignesh said:

how the time and date will taken

 The calendar time and date is calculated in SW, based on the elapsed time, counted by the RTC.