Time_stamping_value?

[MMG]

Hi Nordic Devzone,

First i want to make sure that if the clock being used by softdevice is the LFCLK (32kHz) and its counter register is 24bits ? and which prescaler is being used? because I want to send the local time (clock value ) from one device to another using Bluetooth mesh connectivity, but when i'm reading the time of the receive message from the ( const access_message_rx_t * p_message) the value of timestamp is greater than 24 bits value actually its a 32bit value , so if the counter register in the LFCLK is 24 bits how would it be possible to count up to 32 bits value ? does it mean that the clock begin used for time stamping the receive messages is different than the clock used by softdevice ? And what is the best way to keep track of time while using the softdevice ?

Thank you in advance

[Hung Bui]

Hi MMG,

The timestamp you see in access_message_rx_t is the timestamp when the packet is received. It's a local timestamp counting from the start of current timeslot. Have a look at radio_handle_end_event() in scanner.c

And note that we use TIMER0 to count time, and it's 32bit. Not the 24bit RTC.

Currently we have no use of the timestamp in the receive package yet.

[MMG]

That makes more sense! With another timer there is no need to consider the RTC0. Thank you for the blog post! I hadn't paid that much attention to it before but it looks you had very good accuracy, maybe I will try to include something similar.

The synchronization doesn't have to be very accurate, but I was thinking of one node being the master node, and control the other nodes (slave nodes) time. Possibly with a configuration phase that would run every now and then that would check the drift and the initial offset. Most likely it wouldn't be very accurate since there would be a lot of non-deterministic behaviour. But at least it will not reset in the middle which what I was worried about.

Thanks once again for all your help! It was very educational to receive complete answers on how the time functionality on the device worked!