Re: Measurement Computing "minilab" and "PMD" series (USB interfaces)

Holger, thank you for your fast reply.

As far as I understand, comedi is intended as an abstraction layer. Comedi allows
you to write application programs that continue to work even if you change
your hardware. Consequently, it would be quite appropriate for comedi to support
usb measurement devices.

The PMD 1024LS you mention has DIO and CTR, but no ADC or DAC. So I understand
that your driver supports DIO and CTR, but not yet A/D conversion. On the other
hand, from monitoring the USB channel you are confident that extending the support
to A/D and D/A conversion would be straightforward. Is that correct ? 

If so, this is really good news for me.

If you are ready to freely share your knowledge, I would very much appreciate if you could
send me your read-write program, though I am not the right person to advice how it might
be integrated into comedi.

If you have a short summary of the USB command and data format in plain ASCII, it might
also be appropriate to post them here to the mailing list, for documentation and as a base
for further discussion.

Regards, Joachim

Holger Jakob <jakob_at_ph1.uni-koeln.de> schrieb am 28.09.04 16:57:33:
> 
> On Tuesday 28 September 2004 16:27, Joachim Wuttke wrote:
> > Hi, David, Frank, and others,
> 
> Hi Joachim,
> 
> I posted the following message a while ago:
> 
> Hello Everyone,
> 
> I have a Digital I/O device that uses a 82C55 internally and is connected by 
> USB. There is no documentation or development kit available for linux, and 
> the vendor (Personal Measurement Device) said that some linux group is 
> working on a driver that is not released yet. So I decided to write a linux 
> driver on my own. The protocol used for communication via USB is quite simple 
> (actually I monitored the USB transfer of the device with a Windows tool).
> 
> So, at the present stage I have a small example program that allows me to read 
> and write the ports. There is a 32-bit counter as well. To access USB, I use 
> libusb. However, the device seems to be a USB-HID device, and is thus claimed 
> by the usbhid-module. I think this is supposed to be a much easier way to 
> access the device, but I was unable to get anything useful out 
> of /dev/usb/hiddev0.
> 
> I would like to see this device supported by comedi, so I want to ask here,
> I there is any interest to have this device supported? Because I am no expert
> to the comedi-intera I would also like to know if and how USB devices are 
> supported by comedi?
> 
> Regards,
> Holger
> 
> 
> Because I would prefer to have a user-space only driver a comedi driver 
> (including a kernel-module) would probably need much more work than
> a simple non-comedi user-level library. The alternative libhid has recently 
> made some progress as well, but I have no information on the status and how
> well this lib works with PMDs.
> 
> Are you interested in my (example) code for the PMD 1024LS? A step forward
> would be if someone could write small interface functions for the device.
> 
> Regards,
> Holger
> 
> 
> >    after two years off the list I am back with a data acquisistion
> > question: Do you support the USB devices by Measurement Computing
> >    (http://www.measurementcomputing.com/usb.html) ?
> >
> > Regards, Joachim

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Received on 2004-09-28Z14:39:16