dwm1001 BCNx, SVCx and TWR slot x occpy time

hi, all:

dwm1001 BCNx, SVCx and TWR slot x , how assign their time?

16 BCNx
2 SVCx
15 TWR slots

so 100ms/(16+2+15) = 3ms ?

TWR slot is 5ms, others 1ms, 7ms reserved maybe

The BCN slots are 500 us, service the same.
TWR slot = 10 x 500 us.

So the BCNs 8 ms, SVC 1ms, 15 TWR slots is 75ms and 16 ms reserved (e.g. used during OTA FW update).

hi, zoran:

thanks, why twr slot = 10*500us ? which place describe the information

The TWR slot: tag sends a “group poll” message, 4 anchors reply with “poll” messages, tag sends a “response” and 4 anchors reply with “final” messages. 1 + 4 + 1 + 4 = 10 messages = 10 slots. the slots are 500 us as that is the minimum time needed to send a frame and then for the nRF to process it (read the received message, prepare the response etc.) and be ready to send or receive in time for the next slot.

yeah, anchors receive group poll. all anchors don’t send the poll message at the same time, so they will send in proper sequence for no collistion.

Hi everyone,

I’m don’t know how to get system tick count to calculate the slot of super frame. Anyone else can show me the way, please!
I use xTaskGetTickCount() to get system tick count, but it return tick count in ms. The Super Frame duration is 100ms and slot duration is 500us. Then I can’t calculate exactly slot number.

I’m using decawave example source code at link below https://github.com/Decawave/dwm1001-examples

Thank in advance !

Best regard,