3.6.2. Signal acquisition utility

The Red Pitaya signal can be acquired using the acquire command line utility. It returns raw samples from the ADC buffer to the standard output without calibration compensation. Usage instructions:

redpitaya> acquire
acquire Version: 2.07-651-631657660

Usage: acquire [OPTION]... SIZE <DEC>

--equalization  -e    Use equalization filter in FPGA (default: disabled).
--shaping       -s    Use shaping filter in FPGA (default: disabled).
--bypass        -b    Bypass shaping filter in FPGA.
--gain1=g       -1 g  Use Channel 1 gain setting g [lv, hv] (default: lv).
--gain2=g       -2 g  Use Channel 2 gain setting g [lv, hv] (default: lv).
--tr_ch=c       -t c  Enable trigger by channel. Setting c use for channels [1P, 1N, 2P, 2N, EP (external channel), EN (external channel)].
                        P - positive edge, N -negative edge. By default trigger no set
--tr_level=c    -l c  Set trigger level (default: 0).
--version       -v    Print version info.
--help          -h    Print this message.
--hex           -x    Print value in hex.
--volt          -o    Print value in volt.
--avg                 Outputs the average value for the values in the buffer.
--calib         -c    Disable calibration parameters
--hk            -k    Reset houskeeping (Reset state for GPIO). Default: disabled
--axi           -a    Enable AXI interface. Also enable housekeeping reset. Default: disabled
--debug         -g    Debug registers. Default: disabled
--offset              Offset relative to the trigger pointer [-16384 .. 16384]
    SIZE                Number of samples to acquire [0 - 16384].
    DEC                 Decimation [1,2,4,8,16,...] (default: 1). Valid values are from 1 to 65536

Example (acquire 1024 samples with decimation 8, ch1 with at 1:20, results displayed in voltage):

redpitaya> acquire 1024 8 -1 lv -o
    -0.175803   0.000977
    0.021975    0.001099
    -0.075693   0.000977
    -0.190453   0.001099
    0.004883    0.001221
    -0.046392   0.001099
    -0.200220   0.000977
    -0.014650   0.001099
    -0.019534   0.001099
    -0.195336   0.000977
    -0.041509   0.001099
    ...

redpitaya> acquire

Usage: acquire [OPTION]... SIZE <DEC>

    --equalization  -e    Use equalization filter in FPGA (default: disabled).
    --shaping       -s    Use shaping filter in FPGA (default: disabled).
    --atten1=a      -1 a  Use Channel 1 attenuator setting a [1, 20] (default: 1).
    --atten2=a      -2 a  Use Channel 2 attenuator setting a [1, 20] (default: 1).
    --dc=c          -d c  Enable DC mode. Setting c use for channels [1, 2, B(Both channels)].
                            By default, AC mode is turned on.
    --tr_ch=c       -t c  Enable trigger by channel. Setting c use for channels [1P, 1N, 2P, 2N, EP (external channel), EN (external channel)].
                            P - positive edge, N -negative edge. By default trigger no set
    --tr_level=c    -l c  Set trigger level (default: 0).
    --version       -v    Print version info.
    --help          -h    Print this message.
    --hex           -x    Print value in hex.
    --volt          -o    Print value in volt.
    --no_reg        -r    Disable load registers config for DAC and ADC.
    --calib         -c    Disable calibration parameters
        SIZE                Number of samples to acquire [0 - 16384].
        DEC                 Decimation [1,2,4,8,16,...] (default: 1). Valid values are from 1 to 65536

Example (acquire 1024 samples with decimation 8, ch1 with at 1:20, results displayed in voltage):

redpitaya> acquire 1024 8 -1 20 -o
    -0.175803   0.000977
    0.021975    0.001099
    -0.075693   0.000977
    -0.190453   0.001099
    0.004883    0.001221
    -0.046392   0.001099
    -0.200220   0.000977
    -0.014650   0.001099
    -0.019534   0.001099
    -0.195336   0.000977
    -0.041509   0.001099

redpitaya> acquire
acquire version 0.90-299-1278

Usage: acquire  size <dec>

    size     Number of samples to acquire [0 - 16384].
    dec      Decimation [1,8,64,1024,8192,65536] (default=1).

Example (acquire 1024 samples with decimation 8):

redpitaya> acquire 1024 8
    -148     -81
    -143     -84
    -139     -88
    -134     -82
    ...

To run the signal acquisition utility, perform the following steps:

Load the FPGA image.

redpitaya> overlay.sh v0.94

redpitaya> cat /opt/redpitaya/fpga/fpga_0.94.bit > /dev/xdevcfg

Start the console application.

redpitaya> acquire 1024 8 -1 20 -o
    -0.175803   0.000977
    0.021975    0.001099
    -0.075693   0.000977
    -0.190453   0.001099
    0.004883    0.001221
    -0.046392   0.001099
    -0.200220   0.000977
    -0.014650   0.001099
    -0.019534   0.001099
    -0.195336   0.000977
    -0.041509   0.001099
    ...

Acquisition performance varies between Red Pitaya models. For more information please refer to the Red Pitaya Original Gen board comparison or Gen 2 board comparison.

Note

If all inputs are measuring the same signal, but produce different measurements, check the calibration of your Red Pitaya using the calib utility or the Calibration application.

Source code

The Red Pitaya GitHub repository contains the source code for the acquire utility.