Post by thread:Fw: [EE]: Oscilloscopes

I didn't ask, but am happy to have found your post! :) Thanks for the links! Chris -----Original Message----- From: pic microcontroller discussion list [spam_OUTPICLISTTakeThisOuTMITVMA.MIT.EDU] On Behalf Of mulliganshawn Sent: Monday, January 06, 2003 4:02 PM To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU Subject: Fw: [EE]: Oscilloscopes > Before Christmas, someone had asked me for tutorials on oscilloscope usage. > Now that I'm back at my desk, here they are: > > http://www.bkprecision.com/download/scope/FGGuide.pdf > > http://www.tek.com/Measurement/App_Notes/XYZs/03W_8605_2.pdf > > Both are excellent. Shawn > -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestKILLspammitvma.mit.edu -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body

haven't plunked down yet for an oscilloscope.... what do you need a four channel versus a two channel oscilloscope for? what kinds of things do you do with a four channel? thanks very much. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

You may want to watch various status lines on a PIC at the same time. This will save you having to probe around with just one or two probes. Also you loose one input if you need to need a sync signal. Rick rad0 wrote: > haven't plunked down yet for an oscilloscope.... > > what do you need a four channel versus a two channel oscilloscope for? > > what kinds of things do you do with a four channel? > > thanks very much. > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Mon, 13 Jan 2003, rad0 wrote: *>haven't plunked down yet for an oscilloscope.... *> *> *>what do you need a four channel versus a two channel oscilloscope for? *> *>what kinds of things do you do with a four channel? If you do video, imaging sonar, complex servos (have multilevel plls) then it can be useful. You can also use two+one channels (two normal channels and the third shows the external trigger waveform). Unless you do something like this every day you will seldomly need the 3rd and 4th channels imho. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Tue, 14 Jan 2003, Doug Hewett wrote: *>(1) You may find 4 channels useful when looking at SPI or Microwire: *>(a) data in, (b) data out, (c) clock, (d) slave select. With hawk eyes ;-) I can't see 1MHz signals. Can you ? Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

"Peter L. Peres" wrote: > > On Tue, 14 Jan 2003, Doug Hewett wrote: > > *>(1) You may find 4 channels useful when looking at SPI or Microwire: > *>(a) data in, (b) data out, (c) clock, (d) slave select. > > With hawk eyes ;-) I can't see 1MHz signals. Can you ? > > Peter Sure, with a high enough repetition rate it's -easy- to see nanosecond wide pulses on a GOOD scope. When debugging code/hardware interactions, you put in the shortest loop you can to see where stuff is 'broken'. And I would strongly second the recommendation for a 4 channel scope if debugging SPI/I2C hardware. It's also useful for 'normal' debugging, where you trigger the scope with your chip select or address decoder and then confirm that the /OE, R/W & data lines are doing what they're supposed to. I often find myself using both channels on TWO stacked TEK 465 scopes to get my 4 channels (6 if you count the way I use external trigger as a "channel"). Robert -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

>You may want to watch various status lines on a PIC at the same time. This >will save you having to probe around with just one or two probes. Also you >loose one input if you need to need a sync signal. >Rick 'Scopes have an "external sync" input, no? No need to give up a channel. Barry -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Not necessarily just a sync, but like a previos post said, you might sync on the chip select, and you may also need to see that the chip select is there and stable from the CS driver which you cannot do with just an external trigger. Rick Barry Gershenfeld wrote: {Quote hidden}> >You may want to watch various status lines on a PIC at the same time. This > >will save you having to probe around with just one or two probes. Also you > >loose one input if you need to need a sync signal. > >Rick > > 'Scopes have an "external sync" input, no? No need to give up a channel. > > Barry > > -- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I never use the external sync on my Tek 475. Now I'm thinking I am missing out. Is it basically just another channel that you can't display but only sync off of? If you are only viewing one channel and you want to sync off another signal, is there any advantage to using the external sync input, or would it always be better to put the second signal on the second channel so that you can view it also? So my impression is that you use the external sync when all your real channels are being used and you want to input one more signal that you just need to sync off. Is that right? --BobG {Original Message removed}

Yep. Also, you may not have the necessary gain, AC/DC detection, offset, and of course the viewing of it. Rick "Robert E. Griffith" wrote: {Quote hidden}> I never use the external sync on my Tek 475. Now I'm thinking I am missing > out. Is it basically just another channel that you can't display but only > sync off of? If you are only viewing one channel and you want to sync off > another signal, is there any advantage to using the external sync input, or > would it always be better to put the second signal on the second channel so > that you can view it also? > > So my impression is that you use the external sync when all your real > channels are being used and you want to input one more signal that you just > need to sync off. Is that right? > > --BobG > > {Original Message removed}