3.2.2. Command line utilities

3.2.2.1. Red Pitaya command line utilities

Note

Command line utilities must not be used in parallel with a WEB application.

3.2.2.1.1. Signal generator utility

The Red Pitaya signal generator can be controlled through the generate command line utility, but be aware it interferes with the GUI based Oscilloscope & Generator application. Usage instructions (see Table 7 as well):

redpitaya> generate
 generate version 0.90-299-1278

 Usage: generate   channel amplitude frequency <type>

     channel     Channel to generate signal on [1, 2].
     amplitude   Peak-to-peak signal amplitude in Vpp [0.0 - 2.0].
     frequency   Signal frequency in Hz [0.0 - 6.2e+07].
     type        Signal type [sine, sqr, tri].
Parameters of Signal generator utility
Name Type Range Description
channel int 1/ 2 Output channel selection
amplitude float 0 - 2 [V] Maximal output signal is 2 V peak to peak
freq float 0 - 620000001 [Hz] Frequency can be generated from 0 Hz (DC signal) on*.
<type> string sine / sqr / tri Optional parameter. Signal shape type (sine – sine wave signal, sqr – square signal, tri – triangular signal). If omitted, sine is used.
1 To generate smooth signals, not exceeding Back-End bandwidth, limitations are:
  • 62 MHz (62000000) for sine wave
  • 10 MHz (10000000) for square and triangular waves

The output can be disabled by setting the amplitude parameter to zero.

Example (2 Vpp square wave signal with 1 MHz on channel 1):

redpitaya> generate 1 2 1000000 sqr

Note

Signal generator output impedance is 50 Ω. If user wants to connect the output of the signal generator (OUT1, OUT2) to the Red Pitaya input (IN1, IN2), 50 Ω terminations should be connected at the Red Pitaya inputs through the T-type connector.

Note

For correct operation of the generate tool, it is mandatory that the correct FPGA image is loaded. Please note, the some application can change the FPGA image loaded. To load the FPGA image open a terminal on the RedPitaya and execute the following command:

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

3.2.2.1.2. Signal acquisition utility

The signal from Red Pitaya can be acquired through the acquire command line utility. It will return raw samples from the ADC buffer to standard output, with no calibration compensation. Usage instructions (see Table 8 as well):

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).
Parameters of Signal acquisition utility
Name Type Range Description
size int 0 - 16384 The number of samples to read.
dec int 1, 8, 64, 1024, 8192, 16384 Optional parameter. It specifies the decimation factor. If omitted, 1 is used (no decimation).

Acquire utility will return the requested number of samples with decimation factor for both input channels (column 1 = Channel1; column 2 = Channel2).

Example (acquire 1024 samples with decimation 8):

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

Note

For correct operation of the acquire tool, it is mandatory that the correct FPGA image is loaded. Please note, the some application can change the FPGA image loaded. To load the FPGA image open a terminal on the RedPitaya and execute the following command:

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

3.2.2.1.3. Saving data buffers

It is recommended to use an NFS share to store any temporary data (e.g. the measured signals using the acquire utility). Use a standard mount command to mount your NFS share (example):

redpitaya> mount -o nolock <ip_address>:/<path>  /mnt

The /opt file-system on Red Pitaya, representing the SD card, is mounted read-only. To save the data locally on Red Pitaya redirect the acquisition to a file in the /tmp directory. The /tmp directory resides in RAM and is therefore volatile (clears on reboot).

redpitaya> acquire 1024 8 > /tmp/my_local_file

Alternatively, save the data directly to the NFS mount point:

redpitaya> acquire 1024 8 > /mnt/my_remote_file

3.2.2.1.3.1. Copying data - Linux users

In case NFS share is not available, you can use secure copy:

redpitaya> scp my_local_file <user>@<destination_ip>:/<path_to_directory>/

Alternatively Linux users can use graphical SCP/SFTP clients, such as Nautilus for example (explorer window). To access the address line, type [CTRL + L] and type in the following URL: sftp://root@<ip_address>

../../_images/Nautilus_address_bar.png

Figure: Nautilus URL/address bar.

Type the Red Pitaya password (next Figure). The default Red Pitaya password for the root account is »root«. For changing the root password, refer to buildroot configuration - a mechanism for building the Red Pitaya root file-system, including the /etc/passwd file hosing the root password.

../../_images/Nautilus_password_window.png

After logging in, the main screen will show the directory content of Red Pitaya’s root filesystem. Navigate to select your stored data and use the intuitive copy-paste and drag & drop principles to manipulate the files on Red Pitaya (see next Figure).

../../_images/Nautilus_root_fs.png

3.2.2.1.3.2. Copying data - Windows users

Windows users should use an SCP client such as WinSCP. Download and install it, following its installation instructions. To log in to Red Pitaya, see example screen in next Figure.

../../_images/WinSCP_login_screen.png

Figure: WinSCP login screen.

After logging in, the main screen will show the content of the Red Pitaya root filesystem. Navigate to select your stored data and use the intuitive copy-paste and drag & drop principles to manipulate the files on Red Pitaya (see next Figure).

../../_images/WinSCP_directory_content.png

Figure: Directory content on Red Pitaya.

Select the destination (local) directory to save the data file to (see next Figure).

../../_images/WinSCP_filesave.png

Figure: Select file copy destination.

3.2.2.1.4. Accessing system registers

The system registers can be accessed through the monitor utility. Usage instructions:

redpitaya> monitor
monitor version 0.90-299-1278

Usage:
    read addr: address
    write addr: address value
    read analog mixed signals: -ams
    set slow DAC: -sdac AO0 AO1 AO2 AO3 [V]

Example (system register reading):

redpitaya> monitor -ams
#ID                                                                    Desc                                                                                                                                        Raw                                                                    Val
0                                                                    Temp(0C-85C)                                                                    a4f                                                                    51.634
1                                                                    AI0(0-3.5V)                                                                    1                                                                    0.002
2                                                                    AI1(0-3.5V)                                                                    13                                                                    0.033
3                                                                    AI2(0-3.5V)                                                                    1                                                                    0.002
4                                                                    AI3(0-3.5V)                                                                    2                                                                    0.003
5                                                                    AI4(5V0)                                                                    669                                                                    4.898
6                                                                    VCCPINT(1V0)                                                                    55c                                                                    1.005
7                                                                    VCCPAUX(1V8)                                                                    9a9                                                                    1.812
8                                                                    VCCBRAM(1V0)                                                                    55d                                                                    1.006
9                                                                    VCCINT(1V0)                                                                    55b                                                                    1.004
10                                                                    VCCAUX(1V8)                                                                    9ab                                                                    1.813
11                                                                    VCCDDR(1V5)                                                                    809                                                                    1.507
12                                                                    AO0(0-1.8V)                                                                    2b0000                                                                    0.496
13                                                                    AO1(0-1.8V)                                                                    150000                                                                    0.242
14                                                                    AO2(0-1.8V)                                                                    2b0000                                                                    0.496
15                                                                    AO3(0-1.8V)                                                                    220000                                                                    0.392

The –ams switch provides access to analog mixed signals including Zynq SoC temperature, auxiliary analog input reading, power supply voltages and configured auxiliary analog output settings. The auxiliary analog outputs can be set through the monitor utility using the –sadc switch:

redpitaya> monitor -sdac 0.9 0.8 0.7 0.6

3.2.2.1.5. Monitor utility for accessing FPGA registers

Red Pitaya signal processing is based on two computational engines: the FPGA and the dual core processor in order to effectively split the tasks. Most of the high data rate signal processing is implemented within the FPGA building blocks. These blocks can be configured parametrically through registers. The FPGA registers are documented in the RedPitaya HDL memory map document. The registers can be accessed using the described monitor utility. For example, the following sequence of monitor commands checks, modifies and verifies the acquisition decimation parameter (at address 0x40100014):

redpitaya> monitor 0x40100014
0x00000001
redpitaya>
redpitaya> monitor 0x40100014 0x8
redpitaya> monitor 0x40100014
0x00000008
redpitaya>

Note

The CPU algorithms communicate with FPGA through these registers. Therefore, the user should be aware of a possible interference with Red Pitaya applications, reading or acting upon these same FPGA registers. For simple tasks, however, the monitor utility can be used by high level scripts (Bash, Python, Matlab...) to communicate directly with FPGA if necessary.