Usrp TX mux settings

GNU Radio
1

I think i’ve narrowed down the problems with my code to the mux setting
for
the usrp system. Is there anywhere you could point me to for a list of
possible values for that mux, currently i’m just using one i found in a
demo
program but can’t seem to find a list of all possible values.
-Garrett McGrath

2

On Thu, May 18, 2006 at 08:11:30PM -0400, Garrett McGrath wrote:

I think i’ve narrowed down the problems with my code to the mux setting for
the usrp system. Is there anywhere you could point me to for a list of
possible values for that mux, currently i’m just using one i found in a
demo
program but can’t seem to find a list of all possible values.
-Garrett McGrath

Use the source, Luke :wink:

From usrp/host/lib/usrp_standard.h:

Receive mux:

/*!

  • \brief Set input mux configuration.
  • This determines which ADC (or constant zero) is connected to
  • each DDC input. There are 4 DDCs. Each has two inputs.
  • 

    • 

  • Mux value:
    • 

  • 

  • 3 2 1
    • 

  • 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
    • 

  • ±------±------±------±------±------±------±------±------+
    • 

  • | Q3 | I3 | Q2 | I2 | Q1 | I1 | Q0 | I0 |
    • 

  • ±------±------±------±------±------±------±------±------+
    • 

  • 

  • Each 4-bit I field is either 0,1,2,3
    • 

  • Each 4-bit Q field is either 0,1,2,3 or 0xf (input is const zero)
    • 

  • All Q’s must be 0xf or none of them may be 0xf
    • 

  • 

    • 



*/

bool set_mux (int mux);


Transmit mux:


/*!


    

  • \brief Set output mux configuration.
    • 

  • 

  • 

    

    • 

  • 

    3                   2                   1

    

    • 

  • 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
    • 

  • ±------------------------------±------±------±------±------+
    • 

  • | | DAC3 | DAC2 | DAC1 | DAC0 |
    • 

  • ±------------------------------±------±------±------±------+
    • 

  • 

  • There are two interpolators with complex inputs and outputs.
    • 

  • There are four DACs.
    • 

  • 

  • Each 4-bit DACx field specifies the source for the DAC and
    • 

  • whether or not that DAC is enabled. Each subfield is coded
    • 

  • like this:
    • 

  • 

  • 

    3 2 1 0

    

    • 

  • ±±----+
    • 

  • |E| N |
    • 

  • ±±----+
    • 

  • 

  • Where E is set if the DAC is enabled, and N specifies which
    • 

  • interpolator output is connected to this DAC.
    • 

  • 

  • N which interp output
    • 

  • 

    

    • 

  • 0 chan 0 I
    • 

  • 1 chan 0 Q
    • 

  • 2 chan 1 I
    • 

  • 3 chan 1 Q
    • 

  • 

    • 



*/

bool set_mux (int mux);



























3






In the USRP source code directory, look for the file

doc/html/classusrp__standard__tx.html. Then you should find:


bool usrp_standard_tx::set_mux ( int mux )


Set output mux configuration.


 3                   2                   1



1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0

±------------------------------±------±------±------±------+

| | DAC3 | DAC2 | DAC1 | DAC0 |

±------------------------------±------±------±------±------+


There are two interpolators with complex inputs and outputs.

There are four DACs.


Each 4-bit DACx field specifies the source for the DAC and

whether or not that DAC is enabled. Each subfield is coded

like this:


 3 2 1 0
+-+-----+
|E|  N  |
+-+-----+



Where E is set if the DAC is enabled, and N specifies which

interpolator output is connected to this DAC.


N which interp output




0 chan 0 I

1 chan 0 Q

2 chan 1 I

3 chan 1 Q


Regards,


Pascal