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FPU


OwO 2021/05/20 17:41

There are still people confused about whether FPU is important, so I
tested sweep and measurement performance with and without FPU enabled.
There was exactly zero difference, so this settles the question and
concludes that there is no value in enabling FPU in firmware builds. It
is impossible to get GD32 chips with guaranteed FPU, and having to throw
away chips without it would be (1) wasteful and (2) increase prices more
than it already has. People who keep writing negative ratings
complaining about lack of FPU just makes me regret not closing source
like all other vendors have done.

Robert Mueller 2021/05/20 13:25

Just a note: Thanks for your efforts to serve the best interests of the
owners of these valuable instruments.. I wish you success in educating
those who complain about "problems" which cause no bad consequences..

On Thu, May 20, 2021 at 11:42 AM OwO <OwOwOwOwO123@outlook.com> wrote:

F1RVC 2021/05/20 14:13

I agree with this, the most important is to have at least a well working
official firmware. Unfortunately since February 2021 all official firmware
are making flickering display for me . I have to use only old one to avoid
this problem or using Dislord non official firmware for my NanoVna V2plus4
to make it working well....

Patrice.




Le jeu. 20 mai 2021 à 13:26, Robert Mueller <robertmueller2000@gmail.com> a
écrit :

OwO 2021/05/20 20:29

Thanks and sorry about the rant.

F1RVC: can you check if this one fixes it?
https://nanorfe.com/downloads/20210520/nanovna-v2-20210520-v2plus4.bin

DiSlord 2021/05/20 10:23

FPU does not significantly affect the operating speed.
V2 still displays a picture in parallel with measurements, and the speed limits the waiting time for data to be ready.

Because of what I needed to use FPU:
To measure 371 points, you need a lot of memory, by default there it was only enough for 201 points.

We managed to free up the necessary memory, among other things, using the FFT buffer (for Transform Domain). For this function, I now use the usual one with measurements.
But the problem was that the measurement process was going on, and I needed to have time to carry out the FFT calculations (and this is quite time-consuming floating point calculations) and sometimes if the picture was also displayed in the background, the measured data was overwritten by the not yet finished calculation and there was garbage on the screen.
By using FPU, I solved this problem.

Then, of course, there were optimizations of mathematics, FFT, and this is no longer so relevant.

So once again I will summarize for the default firmware, the presence of FPU does not play any role at all. For my version now, too, although it allows you to reduce the size of the code, since there is not so much space there, the addition of new functions may require its use to reduce the size of the firmware.

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