Author Topic: Protocol type?  (Read 458 times)

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Offline eti

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Protocol type?
« on: October 20, 2020, 03:13:10 am »
Forgive my ignorance, I am probing the output of the COB IC of my "Kaiweets" HT118A DMM, hoping to find RS232 being pumped out, and I came across this waveform (pin # impossible to know, since it's COB)... does anyone recognise this?

{Update}: I've attached a zipped pulseview session too.

Thanks!
« Last Edit: October 20, 2020, 04:34:36 am by eti »
 

Offline eti

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Re: Protocol type?
« Reply #1 on: October 20, 2020, 08:37:59 pm »
Gosh, no one?  ;)
 

Online tautech

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Re: Protocol type?
« Reply #2 on: October 20, 2020, 08:42:02 pm »
Gosh, no one?  ;)
Looked yesterday and all I could see was several clock bursts.  :-//
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Offline eti

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Re: Protocol type?
« Reply #3 on: October 20, 2020, 09:43:08 pm »
Gosh, no one?  ;)
Looked yesterday and all I could see was several clock bursts.  :-//

Thanks for looking :) - I have captured more in "PulseView" and applied the "UART" filter - how does one know how accurate said filter is, though? Is there some form of file format I could share here, to make the full capture more accessible to people who could ID the pulses?

Cheers!
 

Offline eti

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Re: Protocol type?
« Reply #4 on: October 23, 2020, 07:01:41 pm »
Is this any more meaningful?:

 

Offline abyrvalg

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Re: Protocol type?
« Reply #5 on: October 23, 2020, 11:09:00 pm »
This doesn't look like UART at all. Should be a clock line of some synchronous bus transferring 8-bit values (8 shorter pulses separated by a longer one). Are there any other signals belonging to the same bus? (i.e. other pins of the same connectors or PCB pads grouped together with this one). Look for a data signal clocked by this line (some less regular signal with a frequency <=1/2 of this clock, with all transitions during the same clock levels).
 
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Offline eti

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Re: Protocol type?
« Reply #6 on: October 24, 2020, 12:44:04 am »
This doesn't look like UART at all. Should be a clock line of some synchronous bus transferring 8-bit values (8 shorter pulses separated by a longer one). Are there any other signals belonging to the same bus? (i.e. other pins of the same connectors or PCB pads grouped together with this one). Look for a data signal clocked by this line (some less regular signal with a frequency <=1/2 of this clock, with all transitions during the same clock levels).

I'll look, thanks. But if it's not UART, why does the UART filter seem to (sort of) decode it?
 

Offline srb1954

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Re: Protocol type?
« Reply #7 on: October 24, 2020, 01:03:03 am »
This doesn't look like UART at all. Should be a clock line of some synchronous bus transferring 8-bit values (8 shorter pulses separated by a longer one). Are there any other signals belonging to the same bus? (i.e. other pins of the same connectors or PCB pads grouped together with this one). Look for a data signal clocked by this line (some less regular signal with a frequency <=1/2 of this clock, with all transitions during the same clock levels).

It might be just be the clock line of an SPI bus whilst transmitting a multi-byte message.
 
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