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. Usage instructions:

The acquire utility works in two different modes:

  • Normal mode - the utility waits for a trigger event and then acquires the data on all channels.

  • Split trigger mode - the acquisition is split between channels, with each channel having its own trigger. The acquire_p utility is used for this mode.


acquire utility usage

Standard acquire utility usage is as follows:

redpitaya> acquire
acquire Version: 3.00-809-bce7a0397

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, 1A, 2P, 2N, 2A, EP (external channel), EN (external channel)].
                        P - positive edge, N -negative edge, A - any edge. By default trigger no set
--tr_level=c    -l c  Set trigger level (default: 0).
--hex           -x    Print value in hex.
--volt          -o    Print value in volt.
--int                 Interrupt-based operation mode.
--avg                 Outputs the average value for the values in the buffer.
--calib         -c    Disable calibration parameters
--16bit               Enables 16Bit mode
--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]
--version       -v    Print version info.
--help          -h    Print this message.
    SIZE                Number of samples to acquire [0 - 16384].
    DEC                 Decimation [1,2,4,8,16,...] (default: 1). Valid values are from 1 to 65536

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

  1. Load the FPGA image.

    redpitaya> overlay.sh v0.94

  2. 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.


acquire_p utility usage

The acquire_p utility is used for capturing data in split trigger mode. It returns raw samples from the ADC buffer to the standard output. Usage instructions:

redpitaya> acquire_p
Version: 3.00-809-bce7a0397

Application for capturing data in split trigger mode.
Usage: acquire_p [OPTION]... SIZE <DEC>
    SIZE                Number of samples to acquire [1 - 16384].
    DEC                 Decimation [1,2,4,8,16,17,18...65536] (default: 1). Valid values are from 1 to 65536

--att1=a              Use Channel 1 attenuator setting a [1, 20] (default: 1).
--att2=a              Use Channel 2 attenuator setting a [1, 20] (default: 1).

--tr_ch1=c      -1 c  Enable trigger for ch 1. Setting c use for channels [N (now), 1P, 1N, 1A, 2P, 2N, 2A, EP (ext channel), EN (ext channel)].
--tr_ch2=c      -2 c  Enable trigger for ch 2. Setting c use for channels [N (now), 1P, 1N, 1A, 2P, 2N, 2A, EP (ext channel), EN (ext channel)].
--tr_lev1=c           Set trigger level for ch 1 (default: 0).
--tr_lev2=c           Set trigger level for ch 2 (default: 0).

--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.
--version       -v    Print version info.
--help          -h    Print this message.
--hex           -x    Print value in hex.
--volt          -o    Print value in volt.
--calib         -c    Disable calibration parameters
--16bit               Enables 16Bit mode
--int                 Interrupt-based operation mode.
--hk            -k    Reset houskeeping (Reset state for GPIO). Default: disabled
--debug         -g    Debug registers. Default: disabled
--offset              Offset relative to the trigger pointer [-16384 .. 16384]

Source code

The Red Pitaya GitHub repository contains the: