PlutoSDR

Documentation

The documentation is available on the Github Pages.

Basic usage

Using the radio through USB.

using AdalmPluto;

# Opening the radio with 100MHz carrier frequency, 3MHz sampling rate, and 64dB gain.
radio = openPluto(Int(100e6), Int(3e6), 64; bandwidth=Int(20e6));

# Receive the samples
sig = zeros(ComplexF32, 1024*1024) # 1 MiS buffer
recv!(sig, radio);

# Do some treatment
# ...
# ...

# Close the radio
close(radio);

Running the examples

FM Radio

This example records a few seconds of FM radio as WAV to .../AdalmPluto.jl/examples/samples/fm.wav. The duration and station selection have to be modified by editing .../AdalmPluto.jl/examples/fm.jl.

To launch the example (from the root folder of the project) : julia --startup-file=no --project=./examples ./examples/fm.jl.

Benchmark

The actual sampling rate has been measured using the file benchmark.jl. The full results of the last run is available in bench_results.txt.

The functions timed are :

• C_iio_buffer_refill alone, which queries samples from the hardware.
• C_iio_buffer_refill and two C_iio_channel_read for the IQ channels. The read function demultiplexes and converts to host format the data.
• AdalmPluto.refillJuliaBufferRX which is the same thing as before with reinterpret added to convert the samples to ComplexF32.
• recv! which calls the previous function and reads from the Julia buffer into the target array.

With julia lauched from the example folder :

julia> include("benchmark.jl");
julia> plot, results = bench_all();
julia> plot # to display a (very) basic unicode plot

This takes quite a while as each results are timed separately and the radio saturates quite quickly.

Sending samples

⚠️ This is not implemented yet, those are just instructions on how you would do it.

The samples sent need to follow the hardware format. There is some information here and an example here.

Functions that should be used :

• iio_channel_convert_inverse to convert data to the hardware format (endianess and bit alignement).
• iio_channel_get_data_format to get the data format if you want to do the convertion manually.
• iio_buffer_[first|start|step|end] to get the pointers and distance between samples.
• iio_buffer_push to send the data to the hardware.

Artifact

The artifact used for the proof of concept is hosted here.

It has been compiled using the following options :

git clone https://github.com/analogdevicesinc/libiio.git
cd libiio
mkdir build
cd build
cmake ../ -DCMAKE_BUILD_TYPE=Release -DWITH_LOCAL_CONFIG=OFF -DINSTALL_UDEV_RULE=OFF -DWITH_USB_BACKEND=YES -DWITH_NETWORK_BACKEND=YES -DWITH_LOCAL_BACKEND=YES -DWITH_XML_BACKEND=YES -DWITH_SERIAL_BACKEND=NO -DWITH_EXAMPLES=YES
make -j$(nproc)
tar cvzf libiio-0.21-custom.tar.gz libiio.so* tests/iio_* iiod/iiod .version

In order to work properly, the artifact needs a udev rule to access the USB peripherals. It is written in a volatile folder, hence the need the input the sudo password after each reboot. The password prompt does not come from Julia and no information about the password goes through julia. See the __init__ in .../AdalmPluto.jl/src/libIIO/libIIO.jl for more details.