How to measure Scope and Protocol

[kazu]

I would like to ask about the "WaveForms" script (Protocol & Scope).
Use the "Protocol (I2C)" script to issue read commands in succession, and use "Script" to measure the fall time of Ch2 → Ch1 of "Scope" and detect an arbitrary range. The measurement is stopped at that point.

I want to do something like this, can I do it?
If possible, I would appreciate it if you could provide a sample script.

Thank you regards

 

I2C_Measures.pdf

[attila]

Hi @kazu

It could be done like this:

for(var t = 0; t < 10 && wait(0.5); t++){ // wait 500ms
    Scope.single()
    Protocol.I2C.Write(0x2A)
    Scope.wait()
    // Scope trigger on Ch0-SDA falling, T0
    var rg = Scope.Channel2.data // SCL
    var i0 = Scope.Channel2.IndexOfTime(0) // sample index at T0
    var i1 = 0
    // count SCL samples above 1.5V, dT SDA->SCL
    while(i1 < rg.length && rg[i1]>1.5) i1++ 
    var dt = (i1-i0)/Scope.Time.Rate.value 
    print(t, dt*1e6,"us")
}

[kazu]

On 7/23/2021 at 12:10 AM, attila said:

Thank you for the sample.
I'll give it a try.

 

[kazu]

Is it possible to issue the protocol command [Protocol.I2C.Read (0x00,2)] triggered by the change in channel 1 (Hi → Lo)?
I was able to measure the time with the script you taught me, but as the next step, I asked because it became necessary to acquire the change of channel 1 and issue an I2C read.

Thank you

Regards.

[attila]

Hi @kazu

Triggering in Protocol is not supported but you can create a Pattern of such signal and trigger it by Scope like this:

[kazu]

Thank you for your advice.
By the way, I'm not familiar with "Pattern", but if you have a manual, please tell me the URL.
Is it possible to detect the change point of the BUS1 signal and send "Protocol.I2C.Read (0x00,2)" by using "Pattern"?

Thank You

Regards

[attila]

Hi @kazu

See the Help tab or tutorials at https://reference.digilentinc.com/software/waveforms/waveforms-3/start

No. The Protocol uses the Pattern Generator and Logic Analyzer device resources, so it can't be used at the same time.

[kazu]

Thank you for your advice.

I will refer to it.

Thank You

Regards