I2C Decoding?
Can the Propscope decode I2C signals? I'm finding myself working a lot with I2C chips and I'd really like to be able to see what's going on between those chips for troubleshooting purposes.
Thanks!
-Jeff
Thanks!
-Jeff
Comments
This may be helpful, though it does use a scope that has special I2C triggering (which you should be able to replicate on the PropScope by picking out the trigger conditions yourself):
http://www.parallax.com/dl/docs/article/i2cSystemswithHPScope.pdf
Chapter 5 of the student manual that Andy Lindsay is writing has related information, showing step-by-step how to interpret synchronous serial communications (though not specifically I2C) using the PropScope. It's available here:
http://forums.parallax.com/showthread.php?t=124294
(self-promotion: ) If you're going to use it for this purpose you might want to put together a little connector like I made, which you can see here:
http://forums.parallax.com/showthread.php?t=123627&page=2
-Jeff
Not to speak for him, but I'll bet you could convince Hanno that it should be added, eventually, at least. Unless I'm terribly confused, it's just a matter of software (a phrase most easily uttered by the person not responsible for writing that software).
I'm generally only talking about a few bytes of I2C data, so decoding things manually, just for troubleshooting, shouldn't really be a huge hassle.
Thanks! Now off to order my PropScope
-Jeff
Yeah, 1-1/2 years ago or so, I was happy to be able to make an LED blink. I'm used to paying a LOT more for this kind of education.
Serial protocol analysis/triggering has been on the #2 position of my "todo" list for too long now... All the infrastructure is there in the viewport library that propscope is built on- but I want to do it right. Once Andy's book is finished I'll start.
In the mean time- please list the features- and ideally post screenshots of other scopes to show me what you want PropScope to do...
Hanno
Hanno- you are the man!
This is great news. . .do you maintain/build the software that runs the Propscope? Is there something other than the Parallax software I'd need to load to use your stuff?
Long story short, I'm probably not experienced enough to provide a lot of useful feature recommendations, but I was looking at these kinds of screens while choosing a logic analyzer/Oscope:
http://www.usbee.com/axdec.html (this one isn't my favorite)
I prefer the simplicity of this one:
http://www.linkinstruments.com/mso19f.htm
Very nice and clear. . .ACKs/NACKs and the data translated into the individual bits. . .super!
-Jeff
http://hannoware.com
I'm not terribly excited about either of the screenshots you linked to... It needs to be both easier to use and more powerful. Better graphics is good too- as long as it keeps things simple and beautiful. We'll get there... What protocols should it support? I2C, SPI, RS232, MIDI, maybe even USB?
Hanno
-Jeff
Maybe: CAN
I searched for screenshots.
Found this: http://tmetrix.com/downloads/seminars/LeCroy_Serial_data%20_June_08.pdf
It should be something like in the screenshots in this presentation.
Decoded data direct under/over the signal.
SMBus: http://www.maxim-ic.com/app-notes/index.mvp/id/476
Hanno