'PIC & iButton'
I was looking into the single-wire iButtons, and wanted to hook up aprox 100
"reader-stations" spread out over 50,000 square feet, which all funnel down
to a single PC via serial port. (Or perhaps a couple serial ports if need
What I envision is having several pics, each having the capability to
provide contacts to read 5-10 iButtons.. Each of these pics would reside on
some common bus and eventually stream the data to a PC with a serial port.
Each contact station would append a "station-id" to the 64bit serial number
that the iButton reports...
Has anyone been exposed to a setup like this?
Chief Technical Officer
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Winnipeg, MB. R3C 1K2
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gallmark.mb.ca (email) les
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Dr. Imre Bartfai
please clarify. In fact, the main question is, whether you want that
amount of said iButtons (5-10 pcs) exactly at once, or rather you want
only to set up reader stations. That is, iButton reader stations can be
connected to ONE one-wire bus provided there is no collision, i. e. only
one iButton is connected at one time. With other words: one one-wire bus
can serve a vaste amount of reader stations IF there is only one button.
Further: Dallas provides a sophisticated mechanism called Search ROM which
makes possible to connect more Buttons at a time to a particular bus. And
this only one pin of a PIC!
The allowed length of the bus I do not know off the cut, but this can be
the major factor to calculate the number of PICS, which, on the other
hand, can be connected together to a RS-485 bus.
I hope this helps.
On Thu, 21 Oct 1999, Les wrote:
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