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> Zaurus Oscilloscope, using commercial hardware
jfr
post Aug 24 2007, 03:43 PM
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This post is a trawl, to see whether there's any wider interest in an oscilloscope project I've been working on.

The project uses a digital scope manufactured by Syscomp - the DSO-101. It's a two-channel scope, which plugs into a USB port and uses the conputer as its driver and display. You can read lots more about it at Syscomp's web site.

What I've been doing is to port the host software to the Z.

I bought the scope in the first place in connection with a Morse-to-speech project (mentioned before in these forums). I liked the spec and the price, and I particularly liked the fact that the software that runs on the host is open sourced. The software is written in Tcl/Tk, and I've been porting the main functionality to C++/Qt.

The scope hardware is physically bigger than a Zaurus, but not by all that much, so I thought it would be neat to use the Z as a host and thus end up with a pocket-sized oscilloscope system.

I've now got the port working pretty much to my satisfaction (YMMV). The port doesn't have all the advanced features of the original software, but I think it does count as a workable system. My Zauri are still using their original Sharp ROMs, and the program should work on C1000/3000/3100/3200.

(Dis)claimer: When I first bought the scope, I was merely another customer for Syscomp. I then offered them a couple of contributions for the host software, and that progressed to the point where I became a beta-tester for them. From that, I discussed the idea of the Z port and they were immensely supportive, including supplying extra hardware for the purpose. From that, you'll correctly gather that I think these people are Good Guys. But I have no commercial relationship with them - this is an open source project, pure and simple.

Maybe this is just my private toy, but if anyone else would be interested, I'd be happy to share it.

Cheers

John
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gsgmx
post Aug 25 2007, 03:42 AM
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Sounds great,

i might get one of these scopes too. My Z is runnin g Cacko 1.23 now so your hostsw should run now. But i am planning to switch to pdaXii13. Qt apps do run there too, i am not shure whether or not.

The DSO is described as USB Host powered, so does it run direct from the 100mA the Z can supply or does it need more mAmps? So it needs a powered USB hub?

Thks, George
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jfr
post Aug 25 2007, 04:55 AM
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QUOTE(gsgmx @ Aug 25 2007, 12:42 PM)
The DSO is described as USB Host powered, so does it run direct from the 100mA the Z can supply or does it need more mAmps?  So it needs a powered USB hub?
*

It does need a powered hub - the scope draws (I think) about 400mA. Also, the scope spec says it needs USB2, but I've found that the Z's USB1 port does drive it acceptably enough. There's an occasional problem in high-resolution mode (where you can capture 32k samples per channel and then examine the waveform in detail), in that sometimes some sample data will be lost. I haven't tracked that down fully, but I believe it's due to the USB1 issue and I haven't found it to be a significant drawback. My software doesn't flag it up when it happens, but it could easily be made to do so.

Cheers

John
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Drake01
post Aug 25 2007, 07:24 AM
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QUOTE(jfr @ Aug 25 2007, 07:55 AM)
It does need a powered hub - the scope draws (I think) about 400mA. Also, the scope spec says it needs USB2, but I've found that the Z's USB1 port does drive it acceptably enough. There's an occasional problem in high-resolution mode (where you can capture 32k samples per channel and then examine the waveform in detail), in that sometimes some sample data will be lost. I haven't tracked that down fully, but I believe it's due to the USB1 issue and I haven't found it to be a significant drawback. My software doesn't flag it up when it happens, but it could easily be made to do so.

Cheers

John
*

Sounds like a very cool project. I'd also to point out that the Z does have a USB 2.0 port. The USB 2.0 standard can operate at different speeds. (Decided to actually check Wikipedia to get my facts straight) "High speed" is 480Mbps, "Full speed" is 12Mbps, and "Low speed" is 1.5 Mbps. The Zaurus does not run at High speed, but supposedly it supports the rest of the 2.0 protocol.

Out of curiosity, have you run this on a desktop PC? How does it perform on a PC? And this generally works well on a Z?
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pelrun
post Aug 25 2007, 08:57 AM
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Wow, I think I need to start putting away some pennies for this... smile.gif
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jfr
post Aug 25 2007, 03:55 PM
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QUOTE(Drake01 @ Aug 25 2007, 04:24 PM)
Sounds like a very cool project.  I'd also to point out that the Z does have a USB 2.0 port.  The USB 2.0 standard can operate at different speeds.  (Decided to actually check Wikipedia to get my facts straight)  "High speed" is 480Mbps, "Full speed" is 12Mbps, and "Low speed" is 1.5 Mbps.  The Zaurus does not run at High speed, but supposedly it supports the rest of the 2.0 protocol.

Out of curiosity, have you run this on a desktop PC?  How does it perform on a PC?  And this generally works well on a Z?
*

Thanks, Drake01 - I really had thought it was USB1, and I admit I'm still not quite convinced. The output of lsusb -v on my C3000 begins:
Bus 001 Device 001: ID 0000:0000
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10

I thought the last line there was the USB version number, and hence my comment. But I admit to not having checked further, and I'd certainly welcome a reference where I could learn more. I haven't yet plucked up the courage to go and read the full standard...

Desktop PC: the original Tcl/Tk software runs fine on a desktop (Linux, Mac or Windows, though I've only run it under Linux). I haven't gone so far as to try the port on a desktop - if that's what you meant - some of the code assumes it's on a Z, and I wasn't aiming for anything other than a Z port.

Cheers

John
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aeazocar
post Aug 26 2007, 06:28 AM
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jfr,

Congratulations, this is a great project!
I am currently using pdaXrom, I will love to see it running on it.

Please keep us posted...

Alejandro.
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Drake01
post Aug 26 2007, 07:45 AM
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QUOTE(jfr @ Aug 25 2007, 06:55 PM)
Thanks, Drake01 - I really had thought it was USB1, and I admit I'm still not quite convinced. The output of lsusb -v on my C3000 begins:
Bus 001 Device 001: ID 0000:0000 
Device Descriptor:
  bLength                18
  bDescriptorType        1
  bcdUSB              1.10

I thought the last line there was the USB version number, and hence my comment. But I admit to not having checked further, and I'd certainly welcome a reference where I could learn more. I haven't yet plucked up the courage to go and read the full standard...
*

That's interesting. I had never actually checked that before. The documentation I've read on the Wiki's all states that it's USB 2.0, but not running at high speed. This output seems to imply something else.
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boardboyd
post Aug 28 2007, 08:43 AM
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Just to add, I'm in support of this project and would be interested it. I guess I'll also have to stop buying that extra coffee/day to save up for the hardware.
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speculatrix
post Aug 28 2007, 02:17 PM
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am definitely interested... in fact I talked to a UK distributor of one USB scope (I think they were called Elan) and at the time they didn't/wouldn't do a linux driver; it was also about US$300 or so, and I decided against it.

I did wonder whether the microphone input could be pressed into service as an ADC using suitable signal conditioning.
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jfr
post Aug 28 2007, 03:46 PM
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QUOTE(speculatrix @ Aug 28 2007, 11:17 PM)
am definitely interested... in fact I talked to a UK distributor of one USB scope (I think they were called Elan) and at the time they didn't/wouldn't do a linux driver; it was also about US$300 or so, and I decided against it.

I did wonder whether the microphone input could be pressed into service as an ADC using suitable signal conditioning.
*

I think the microphone input could certainly be used for a scope program, but I wanted something with a bandwidth from DC, and a "proper" high-impedance input that would take standard scope probes and not load the circuit under test. The DSO-101 has a 2MHz bandwidth and a sampling rate up to 20MHz, which was plenty for my needs and which comfortably exceeds anything the mic input could deliver. But if anyone were to put together a scope program using the mic input, I imagine there would be interest in that too.

Well, there's clearly interest in this thing. I'm now working further on the software, with the idea in mind of a demo mode - try the software without having to buy the hardware first. I'll also try to put together a few screen shots and explanations, to give an idea of what the GUI is like.
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speculatrix
post Aug 30 2007, 01:55 PM
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definitely very interested, whether the source was microphone, usb-based ADC (such as a proper scope module), or CF module!

for a while now I've toyed with the idea of building a general-purpose I/O module using a CF development kit with a CF extender. perhaps people know that the Handspring variant of Palm had a slot for expansion modules and it was basically a PCMCIA slot in a special form. It'd be nice if the Z could be similarly used.
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Da_Blitz
post Aug 31 2007, 01:53 AM
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mm, cant believe i missed this post, i am thinking of getting one of these now.

very very intresting wink.gif

edit:

just noted they do paypal, now i am very very intrested, been waiting for somthing like this for ages
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louigi600
post Aug 31 2007, 04:31 AM
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I've been using on my x86 pc (with linux naturally) a software that does bothe oscilloscope and spectrum analisys (within the audio band) without any additional hardware. The software is xoscope ... I've not attempted to build it for Z and it's not the kind of software I plan to use on my Z but you might like to have a go at building it for Z ;-)
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Da_Blitz
post Aug 31 2007, 05:13 AM
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xoscope is nice but it has its limits, mainly bieng limited to the sampaling freq. up to less than half the sample rate (ie 48000hz becomes 24000hz max) this might be fine for some people but for some things you need a higher sampling range

the only real down side i can see on this thing (for me at least) is the 2mhz capture rate, somthing higher would have been nice but its better than nothing and is most likly fine for what i will do with it
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