HackRF Shell: (Learning) Delays

I wanted to move on quickly from completing the FFT interface, on to FM demodulation. However, I realized that if the rest of the project was going to practical and modular, I would need some kind of block style I/O buffer management system, like GnuRadio has. And as I started to pursue that, I realized that I would need to properly modularize my code.

Up until now, all the functions were either being dumped into the default module by the C code, or loaded from one Scheme file in the source directory. I took all the external C code and organized it in sensible module divisions, and then took all the C-based Scheme primitives and put them in two modules ((sdr primitives) and (sdr hackrf primitives)). Those two modules are created and loaded when HackRF Shell is launched, while the other modules can be compiled independently.

That all required taking the time to actually learn how the module system works, as well as understanding how to create and fill-out modules through the C interfaces. So, not much amazing progress to the outside observer, but I learned a lot. The FFT demo function is still working:

One neat thing about programming in Guile is that you can jump into various modules at any time, to play around in them or see what variables are defined in them (private and public):

christopher@nightshade:~/Repos/hackrf-shell$ ./hackrf-shell 
HackRF Shell, copyright 2019 Christopher Howard

Initializing primitive functions.
Entering the Scheme shell.

GNU Guile 2.2.3
Copyright (C) 1995-2017 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> (set! %load-path (cons "/home/christopher.qlfiles.net/Repos/hackrf-shell" %load-path))
scheme@(guile-user)> ,m (sdr hackrf util)
scheme@(sdr hackrf util)> ,b
hackrf-sensible-defaults #<variable 56314e6aaac0 value: #<procedure hackrf-sensible-defaults (d)>>
filename                #<variable 56314e6aa940 value: #<undefined>>
timed-read              #<variable 56314e6aa8a0 value: #<procedure timed-read (d file-path start-h start-m end-h end-m)>>
hackrf-cb-rx-to-file    #<variable 56314e6aa990 value: #<procedure hackrf-cb-rx-to-file (filename)>>
out                     #<variable 56314e6aa9e0 value: #<undefined>>
when-hour-min           #<variable 56314e6bd660 value: #<procedure when-hour-min (h m l)>>
hackrf-cb-rx-to-stream  #<variable 56314e6aaa30 value: #<procedure hackrf-cb-rx-to-stream (out)>>
cb-fft-to-gnuplot       #<variable 56314e6aa8f0 value: #<procedure cb-fft-to-gnuplot (center-freq samp-rate averaging-alpha)>>
scheme@(sdr hackrf util)> hackrf-
hackrf-cb-rx-to-file                  hackrf-open                           hackrf-set-sample-rate
hackrf-cb-rx-to-stream                hackrf-sensible-defaults              hackrf-set-vga-gain
hackrf-close                          hackrf-set-baseband-filter-bandwidth  hackrf-start-rx
hackrf-disable-amp                    hackrf-set-freq                       hackrf-stop-rx
hackrf-enable-amp                     hackrf-set-lna-gain                   
scheme@(sdr hackrf util)> ,m (sdr util)
scheme@(sdr util)> ,b
bv-complex-to-mag       #<variable 56314e6b4700 value: #<procedure bv-complex-to-mag (complex-float-bv n_complex_nums dest-bv)>>
freq-shifter            #<variable 56314e6b4670 value: #<procedure freq-shifter (freq samprate)>>

The next step in my project will be to work out my block-style I/O buffer management system, which will require me to re-learn GOOPS, Guile’s object oriented programming extension, so that will likely still take a while.

git clone git://git.librehacker.com/pub/git/hackrf-rkt.git


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