- From: Bernd Porr <BerndPorr_at_f2s.com>
- Date: Sat, 19 Mar 2005 20:00:39 +0000
It's not about the resolution. It's just about the NAN after the
conversion. But you are right. The user can use the raw data. I'll
change maxdata to 4096.
/Bernd
www: http://www.berndporr.me.uk/
http://www.linux-usb-daq.co.uk/
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Frank Mori Hess wrote:
> On Monday 28 February 2005 09:24 am, Bernd Porr wrote:
>
>>Dear all,
>>
>>does it make harm if we change the "data==0" into "data>=0" in
>>comedi_to_phys?
>>
>>The reason is that I use bit #12 to signal an out-of-range with a 12 bit
>>A/D converter. Bits 0 to 11 carry the data. 0..4095 is the "normal"
>>range and values from 4096 to 8191 signal out of range.
>>
>
>
> The driver shouldn't return any values larger than maxdata. The user isn't
> required to use comedi_to_phys() after all, or may have changed the the
> oor behavior. Plus any scheme you come up with won't be useful in general
> since 16 bit cards don't have any spare bits to play with. By having a
> seperate out-of-range bit, you are only adding two more useful values,
> from 4094 to 4096 on a 12 bit card. That's only 0.02% improvement in
> resolution.
>
Received on 2005-03-19Z20:00:39