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.

[Hung Bui]

Hi MMG,

We have to make it very clear about the softdevice here.

The softdevice is not involved in Mesh activity. The Mesh stack is not the softdevice. The mesh stack runs on top of the timeslot mechanism provide by softdevice. When starting a timeslot period, TIMER0 is reset.

What is your plan with timestamp/global time ? If you don't plan to do anything with for example time synchronization between nodes, you really don't need to worry about timestamp.

The timestamp can be basically explain as the TIMER0 is started when the timeslot starts. Then when a packet arrive on RX, the current value of TIMER0 will be assigned to the timestamp inside access_message_rx_t.