Hi all,

my intention is to read data stored in the DS1971  (256-Bit EEPROM
iButton<http://www.maxim-ic.com/datasheet/index.mvp/id/2823>1-wire
memory)

As far I have the Passive 9-pin (DS9097) 1-Wire
adapter<http://owfs.sourceforge.net/adapters.html>+ DS9092  Touch
Probe Read Head
<http://www.maxim-ic.com/datasheet/index.mvp/id/2974>connected to my
Linux box.

It means the DS1971 iButton will be touched/placed to the 1-wire bus just
sometimes (occasionally)

As far I do not have DS1971 EEPROM, so I am doing my experiments with DS1990A
iButton (ROM) <http://www.maxim-ic.com/datasheet/index.mvp/id/2829>.

I have successfully installed pyowfs and I can do following:

from pyowfs import Connection
connection = Connection("/dev/ttyS1")
s = root.find (type="DS1990A")[0]
print s

As far as good.

In my project I would like to have an infinite loop which checks if somebody
touched/placed iButton to the "Read Head" and if yes, it reads the data from
the iButton memory.

Just to test "proof of concept", I have the my iButton permanently fixed to
the 1-Wire bus.
When I execute the code mentioned above it takes about 7 seconds to print
out the result.

*My question:*

Is there some method how to check/detect presence of the device on the bus
much faster (say 1-2 seconds)?

Can, for example, the DS9097U RS-232 Serial Port
Adapter<http://www.maxim-ic.com/products/ibutton/products/readers.cfm#rs232>or
the DS9490R
USB Port 
Adapter<http://www.maxim-ic.com/products/ibutton/products/readers.cfm#rs232>improve
the speed of detection?

Or is there some SW trick (buffer etc..) how get results faster?


Thanks for your hints

Petr Jakes
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