Auto-find threshold

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fastelectron
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Joined: Tue Jun 26, 2018 9:51 am

Auto-find threshold

Post by fastelectron »

Hi

I use PicoScope6 for Win10 and do SPI-decoding. I have troubles configuring appropriate thresholds to sense the signals to be decoded or to be used as clock. The issue comes up because the offset being used for displaying the signals "stacked" interferes with the offset/value of the threshold for reading the digital SPI-signals.

Proposed solutions:
(1) Please implement a button "find threshold" that automatically sets the threshold on an appropriate value guessed from the sensed signal. Every usual/modern hardware scope has this, but PicoScope obviously not (yet).
(2) Please implement the visualization of the threholds in the scope-region of the GUI and allow configuration by mouse.

Thx for a good solution!

Martyn
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Re: Auto-find threshold

Post by Martyn »

fastelectron wrote:The issue comes up because the offset being used for displaying the signals "stacked" interferes with the offset/value of the threshold for reading the digital SPI-signals.
Not sure I understand this point.

When enabling an SPI decode when you add a channel, as data/clock/chipselect, it should guess the threshold and hysteresis according to the signal that is present, not how it is displayed on the screen. Threshold will be half way between the Max and Min on the trace, and the threshold will be around 40% of pk to pk. If the signal is noisy I would suggest setting hysteresis manually to around 10%

Adding a visualization show the detection threshold is a good idea, and I will pass that onto the team. We have this with the Deep Measure functionality that is present with PicoScope 6.13 and later versions of the software.
Martyn
Technical Support Manager

fastelectron
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Re: Auto-find threshold

Post by fastelectron »

Martyn, yes when for the first time I set up an SPI-decoder, thresholds are automatically chosen. But when the next day I have to use different channels for MOSI / MISO / CLK / CS ... based on the same channel-settings-file, the auto-setup does not take place. In that case I must include the display-offset into manually guessing the appropriate threshold. For this case, (a) seeing the thresholds or (b) a button for refinding optimal thresholds would be a very welcome feature.

Martyn
Site Admin
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Posts: 4491
Joined: Fri Jun 10, 2011 8:15 am
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Re: Auto-find threshold

Post by Martyn »

Understood, I will pass on the information to our development team.
Martyn
Technical Support Manager

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