Perhaps I chose the wrong polarity when first designing the PIO interface. The 
thought is when the PIO is "on" as a switch, it is conducting and an LED (for 
instance) will light. Of course it is conducting to ground, and so the sensed 
voltage will be ground (zero) rather that Vdd (5V=logical 1) which can be 
confusing. It doesn't help that the internal 1-wire connand for conducting is 
to set the bit 0. 

Sorry about your lost day. I can't replace it.

Paul

On Monday 03 October 2005 05:08 pm, Petr wrote:
> Thanks to the "Owfs and DS2413 -- SOLVED" topic on this list, the
> problem is solved and I am able to initialize the LCD display
> flawlessly.
>
> My feeling was I have to send (write) "1" to the PIO if I need to get
> "1" (HI, 5V) on the DS2408 data pin. Opposite is the truth.
>
> For example if you write:
> PIO_ALL="1,1,1,1,1,1,1,1,"
>
> you will get LO TTL logic level on the all data pins of the DS2408.
>
> It took me the whole day to get it working :)
>
> Petr
>
> PJ> Simon Natterer <simon <at> natterer-legau.de> writes:
> >> Paul Alfille wrote:
> >> >In short, the datasheet is confusign to me. I gather there is a mode
> >> >where the DS2408 is used for relatively high-speed communication
> >> > through it's PIO pins, with the strobe pin used for handshaking. This
> >> > fits poorly into the OWFS model. OWFS pretends the 1-wire devices are
> >> > block-devices (think of 1-wire as a scsi controller), not a character
> >> > devices (like a serial line).
> >>
> >> It seems to work for me! The RSTZ pin signals correctly
> >> when the written data is valid, for me it is connected to
> >> the display-enable-pin and the display works. So I think
> >> the RSTZ pin generates a falling edge after each
> >> byte is written.
> >> So if in owfs strobe is set to 1 it has this behavoir, if it
> >> is set to 0 the RSTZ pin is used as a reset pin.
> >> I don't see a problem.
>
> PJ> Simon,
>
> PJ> I am trying to experiment with DS2408 to drive LCD display. I am trying
> to write PJ> the code in OWPython binding. But I can't even initialize the
> LCD display. Can PJ> you post the snippet of the LCD initialization code
> please?
>
> PJ> Thanks a lot
>
> PJ> Petr
>
>
>
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