User payload data transmission between A2A and T2A using poll messages


I want to transmit some payload data via the TREK1000.

I referred to the instructions given in “”. I thought of embedding my payload data in the poll message without disturbing the ranging sequence.

Will it be possible to encapsulate my payload data in the poll message(when the tag state machine is @ TA_TXPOLL_WAIT_SEND), by writing the payload message(which is less than 88 Bytes) from 11th frame buffer index onwards?


When the poll is sent, will it be always correct to read my payload message from onwards the same index that we sent from “dw_event->msgu.rxmsg_ss.messageData”, when the anchor state machine is @ TA_RX_WAIT_DATA state?

Glad for a bit of prompt advice, since many of my attempts were failed :no_mouth:

Thanks in advance,



If you are not sure how to add data to an existing message then please look at the the TREK source code
DecaRangeRTLS_ARM_Source_Code_Guide.pdf (1.4 MB)
and look at example code we have. eg 1a , simple TX.
I also send you the example API have a look at for example dwt_writetxdata.DW1000_Software_API_Guide_rev2p7.pdf (1.5 MB)

When you have an issue make sure that the length of tx message may need to be changed (from the default size) to account for the extra data. Then on the receiving side put a breakpoint and check you have received the expected length and then read out the data buffer.

As you could change the TREK TWR code to meet your requirement, you could consult APS013 to do so.
APS013 DW1000 and two way ranging.pdf (941.8 KB)