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Rigol MSO5074 Logic Analyzer issues
jerryk:
I'm trying to trouble shoot a startup sequence for an I2C LCD display. I have two libraries that I'm trying. One works and the other does not. I wanted to contrast the two startup sequences using the LA as a debug tool.
My assumption is to set the scope on single event trigger and set a time base that will capture the entire startup sequence. Then examine the decoded I2C streams data. I see no other way than to zoom in. I'm new to this and may be going about it wrong. I'm not trying to blame the scope.
Setting that aside I was just wanting to learn how to use the LA on my scope and this project seemed like the time to get familiar with the LA function.
Jerry
Fungus:
--- Quote from: jerryk on September 22, 2024, 09:18:19 pm ---I'm trying to trouble shoot a startup sequence for an I2C LCD display. I have two libraries that I'm trying. One works and the other does not. I wanted to contrast the two startup sequences using the LA as a debug tool.
--- End quote ---
Usually it's much easier to compare the source code...
Or hack the library to print all the data it sends over i2c on the serial console in HEX format.
--- Quote from: jerryk on September 22, 2024, 09:18:19 pm ---My assumption is to set the scope on single event trigger and set a time base that will capture the entire startup sequence. Then examine the decoded I2C streams data. I see no other way than to zoom in. I'm new to this and may be going about it wrong. I'm not trying to blame the scope.
--- End quote ---
Decoders have "event tables" that show all packets as a list.
tggzzz:
--- Quote from: jerryk on September 22, 2024, 09:18:19 pm ---I'm trying to trouble shoot a startup sequence for an I2C LCD display. I have two libraries that I'm trying. One works and the other does not. I wanted to contrast the two startup sequences using the LA as a debug tool.
My assumption is to set the scope on single event trigger and set a time base that will capture the entire startup sequence. Then examine the decoded I2C streams data. I see no other way than to zoom in. I'm new to this and may be going about it wrong. I'm not trying to blame the scope.
Setting that aside I was just wanting to learn how to use the LA on my scope and this project seemed like the time to get familiar with the LA function.
Jerry
--- End quote ---
Sounds like a job for a BusPirate5, or similar.
It also sounds like a good way of "tapping the wheels" (railway wagons) or "kicking the tyres" (cars) before taking the new toyl out for a journey :)
NE666:
--- Quote from: tggzzz on September 22, 2024, 10:14:38 pm ---Sounds like a job for a BusPirate5, or similar.
--- End quote ---
I have to agree. I understand the OP's desire to use and learn the tool they have rather than further investment and I think it's possible to do so, using combinations of the methods/features described above. However, a totally different question is "is this the fastest, easiest and/or most efficient and comfortable way to do this" and there I'd have to say no.
For comparing the content of long sequences of message exchanges and being able to search such content flexibly, the UI of PC-attached tools is far better suited, imho and experience. If it were me, I'd be investing 10USD or so in one of the myriad "Saleae LA clones" and using that in conjunction with the openly available Sigrok Pulseview software for this particular task.
jerryk:
Every time I visit this forum I learn something. Every other visit I seem to spend some money. So I have a cheep clone LA on the way and maybe that will help me reconcile the problems I'm having using Rigols LA.
As for my ability to use this Rigol for decoding I currently have the string "Press key" in a while(1) loop being displayed on the LCD. I cannot find that string or most of it's characters using LA. I have tried the event table, zoomed in on the data stream and manually decoded each data byte, and used the trigger function to the best of my ability and can't even to a single trigger on the first letter in the string"P" hex 0x50.
I'm sure I need to be taken out the wood shed and whacked a few times on the head so feel free. I just want to learn. One other point to notice is the LA settings in the Acquisition menu are greyed out. Maybe a feature in higher end models?.
I'm sure the clone LA and Sigrok are going to help me learn and formulate a better understanding of my failing with this scope's LA. I wasn't sure if the BusPirate5 was a serious suggestion but will look at it too.
As always - Thanks for the help.
Jerry
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