The value of CIR rigester 0x25


I tried to read the CIR data (rigester 0x25). Tag and anchor are working on SS module, and the software is the ranging demo supplying by official. While the value is always equal 0, and the distance information is right.
Can anyone explain or share any documents related to accumulation of preamble symbols to estimate CIR ?

My TX/RX configuration is as below. the result plot is attached !
5, /* Channel number. /
DWT_PRF_64M, /
Pulse repetition frequency. /
DWT_PLEN_128, /
Preamble length. Used in TX only. /
Preamble acquisition chunk size. Used in RX only. /
10, /
TX preamble code. Used in TX only. /
10, /
RX preamble code. Used in RX only. /
0, /
0 to use standard SFD, 1 to use non-standard SFD. /
DWT_BR_6M8, /
Data rate. /
PHY header mode. /
(129 + 8 - 8) /
SFD timeout (preamble length + 1 + SFD length - PAC size). Used in RX only. */

As soon as you enable receive the CIR memory is reset.
If you are getting all 0 in the CIR then the most common cause is that your code is re-enabling receive before reading the CIR data.

Thank you for your reply, Is there some example code i can use to read the CIR memory?


See example code 2c: simple RX with diagnostics, as part of the API examples.
CIR is well descriped in the API example document.

The API doc is attached. The whole package including the example codes, incl 2c , can be downloaded from our websitie DW1000_Software_API_Guide_rev2p7.pdf (1.5 MB)