capture duration with OLS really short

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capture duration with OLS really short

Postby busowner666 » Sat Apr 09, 2016 11:47 am

Hi
I just acquired a logic sniffer for personnal fun.
So i took a board with a winbond SPI flash and wire it to the sniffer; then i lauched ols (from AUR Arch).

I tought that i will be able to capture the full boot process. but the maximum capture size that i got is 223 ms .

I don't undertand in practise what i should do if i want to analyse an unknow board ? set up trigger on CS low ?

Or m i missing something ? Is this the normal behavior ?

I updated to latest firmware with OLS_Updater too.

Best Regards
busowner666
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Re: capture duration with OLS really short

Postby sre71 » Sun Apr 10, 2016 6:50 am

Hi busowner666,
you are welcome!
Actually the maximum capture size depends on sample rate you are using.
OLS has 216K block RAM that can support different memory configurations depending on how many channels are used:

8 channels with 24K sample depth
16 channels with 12K sample depth
32 channels with 6K sample depth

Unless RLE is in use the total acquisition time is the fraction of the available sample depth on sampling rate.
So for instance, considering RLE is off, with 8 channels there are 24K sample depth and by sampling at 200MHz it is 24K/200MHz=120us as lasting time for the acquisition.
By using RLE compression the lasting time will be increased.
In this case, regardless by the real number of channels needed for the acquiring, it's better setting the client for all 32 available because it extends the maximum lasting time for the acquisition.
Please take a look at these:

viewtopic.php?f=23&t=1711&p=59523&hilit=FPGA+V

viewtopic.php?f=23&t=1711&p=59523&hilit=FPGA+Verilog+Demon+Core+AdvTrigger+Meta+RLE+Ti#p59523

Good luck!

Regards,
sre71
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Re: capture duration with OLS really short

Postby busowner666 » Sun Apr 10, 2016 12:52 pm

Thanks i understood;

Need some more practise and discipline then with corectly crafted triggers :)
busowner666
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