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Desktop DSO for hardware and firmware development of MCU systems

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tautech:
Further decode and zoom examples.....
All I have with SPI signal is STB-3

Wilson__:

--- Quote from: KungFuJosh on September 12, 2024, 05:09:12 pm ---If you have the budget to go higher than the SDS2000X Plus, then compare it with the SDS2000X HD. Either one would be a great scope for your needs

--- End quote ---
Many thanks for info.  My use is design verification.  Use DSO to inspect signal lines to confirm that there is no abnormal glitch nor invalid signal. Are below correct?

1. The MCU and external chips works at 10MHz SPI clock.  Likely these silicon are tens of nm node and will not response to glitch that is many times narrower than the normal 10MHz wanted-signal.

2. SDS2000X Plus is 1 or 2GSa/s in 4 or 2 channel mode.  So, I got 100 to 200 dots for the 10MHz signal.  Spec. also says 1ns peak detection.  Presumably, refers to best case signal at full swing voltage (3.3 volts).  Presumably, the scope will detect lower-voltage glitch at, says, 1 volt, of a few ns long. 

3. SDS2000X Plus will do the job, right?  If the scope does not see any glitch, the glitch energy, (voltage multipy time) should be too weak to cause the chip to response, right?

2N3055:

--- Quote from: Wilson__ on September 13, 2024, 04:36:31 pm ---
--- Quote from: KungFuJosh on September 12, 2024, 05:09:12 pm ---If you have the budget to go higher than the SDS2000X Plus, then compare it with the SDS2000X HD. Either one would be a great scope for your needs

--- End quote ---
Many thanks for info.  My use is design verification.  Use DSO to inspect signal lines to confirm that there is no abnormal glitch nor invalid signal. Are below correct?

1. The MCU and external chips works at 10MHz SPI clock.  Likely these silicon are tens of nm node and will not response to glitch that is many times narrower than the normal 10MHz wanted-signal.

2. SDS2000X Plus is 1 or 2GSa/s in 4 or 2 channel mode.  So, I got 100 to 200 dots for the 10MHz signal.  Spec. also says 1ns peak detection.  Presumably, refers to best case signal at full swing voltage (3.3 volts).  Presumably, the scope will detect lower-voltage glitch at, says, 1 volt, of a few ns long. 

3. SDS2000X Plus will do the job, right?  If the scope does not see any glitch, the glitch energy, (voltage multipy time) should be too weak to cause the chip to response, right?

--- End quote ---


You are doing too much of presumptions.

1ns Peak detection means it is in peak detect mode.
In which it will detect a 1ns pulse.

How wide pulse it will detect in normal sampling mode depends on rise/fall times of the pulse.
If pulse has sub ns edges, it will pretty much detect a 3ns pulse with full amplitude.
To cut the story short, SDS2000X+ ( with full BW) is going to be more than fast enough to look into SPI. 

But we are suddenly talk about low digit ns. To deal with that you need 1GHz + scope ...
And some good probing.

Even to achieve full BW of SDS2000X+ your biggest problem will be probing and will be most limiting factor.

Wilson__:

--- Quote from: 2N3055 on September 13, 2024, 04:49:20 pm ---To cut the story short, SDS2000X+ ( with full BW) is going to be more than fast enough to look into SPI.

Even to achieve full BW of SDS2000X+ your biggest problem will be probing and will be most limiting factor.

--- End quote ---
Sorry, coming from thru-hole age.  How to probe QFN chip SPI signals?  'Test version' PCB with test point?

Googled says, https://www.edn.com/oscilloscope-probe-accessories-its-the-little-things-that-matter/

tggzzz:

--- Quote from: Wilson__ on September 13, 2024, 04:36:31 pm ---1. The MCU and external chips works at 10MHz SPI clock.  Likely these silicon are tens of nm node and will not response to glitch that is many times narrower than the normal 10MHz wanted-signal.

--- End quote ---

Don't bet on it. Or rather it depends on "how many".

If it is important, measure it, taking account of PSU voltage, temperature, phase of the moon, chip manufacturer, IC datestamp etc.

In digital circuits the frequency is unimportant, but the timing is important. If you violate, say the thold, then it doesn't matter if the signal is 1MHz or 1Hz (and unlike tsetup it won't be ameliorated by reducing the clock frequency)

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