Sub register for Accumulator CIR memory

Wireless Connectivity Ultra-Wideband
1

Hello,
I want to plot the CIR. The register is 0x25, but I could not find the subregister. please let me know what is it?

2

The sub register is the point in the CIR that you want the data for. So start at 0 and proceed to sub register 4063 (for 64 MHz PRF)

From section 7.2.38 of the user manual:

NB: Because of an internal memory access delay when reading the accumulator the first octet output is a dummy octet that should be discarded. This is true no matter what sub-index the read begins at.

reg:25:000  CIR[0].real.lo8 Low 8 bits of real part of accumulator sample 0
reg:25:001  CIR[0].real.hi8 High 8 bits of real part of accumulator sample 0
reg:25:002  CIR[0].imag.lo8 Low 8 bits of imaginary part of accumulator sample 0
reg:25:003  CIR[0].imag.lo8 High 8 bits of imaginary part of accumulator sample 0
reg:25:004  CIR[1].real.lo8 Low 8 bits of real part of accumulator sample 1
reg:25:005  CIR[1].real.hi8 High 8 bits of real part of accumulator sample 1
reg:25:006  CIR[1].imag.lo8 Low 8 bits of imaginary part of accumulator sample 1
reg:25:007  CIR[1].imag.lo8 High 8 bits of imaginary part of accumulator sample 1

So if you read 5 bytes starting at sub register 0 you will get one byte of undefined junk followed by 4 bytes containing the first sample.
If you read 5 bytes starting at sub register 4 you will get one byte of undefined junk followed by 4 bytes containing the second sample.

3

Hi AndyA,

Thank you. I got only zeros :frowning: Do you have any idea to solve my problem?

4

When are you reading the data?
As soon as you enable receive that memory is reset. So you need to read the CIR data after a valid receive event and before you re-enable receive. This caught me out at first since my code path was to read the packet contents and then if no reply needed to be sent e-enable receive before doing any further processing.
If you have something similar going on then you’ll only ever get 0 for those values.

The other cause that springs to mind is if you were trying to read the CIR data one byte at a time rather than in larger transfers. As noted above the first byte returned is invalid, you need to read a minimum of 2 bytes from the CIR register to get any data.

5

OK, Thank you AndyA.