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OWC(4)			     Kernel Interfaces Manual			  OWC(4)

NAME
     owc -- Dallas Semiconductor 1-Wire Controller

SYNOPSIS
     device owc

DESCRIPTION
     The  owc  module  implements Dallas Semiconductor 1-Wire signaling.  It at-
     taches the ow(4) driver 1-Wire bus protocol.  The owc device implements the
     Link Layer of the 1-Wire bus protocol stack.

     Bit banging a pin on a gpiobus(4) is the only supported  controller.   Both
     standard  and  overdrive  transfer timings are implemented.  Strong pull-up
     functionality needed to support parasitic mode is not implemented.

     To enable 1-Wire for FDT systems requires modifying the DTS for your  board
     to add something like:

     / {
	     ...
	     onewire {
		     compatible = "w1-gpio";
		     gpios = <&gpio 4 1>;
	     };
	     ...
     };

     The  gpios  property describes the GPIO pin the 1-Wire bus is connected to.
     For   more   details   about   the   gpios   property,    please	 consult
     /usr/src/sys/dts/bindings-gpio.txt.

     On a device.hints(5) based system these values are required for the owc:

     hint.owc.%d.at	The gpiobus you are attaching to.

     hint.owc.%d.pins	This is a bitmask that defines a pin on the gpiobus that
			is to be used for the 1-Wire bus.  For instance, to con-
			figure	pin  10,  use the bitmask of 0x400.  Please note
			that this mask should have only one bit set  (any  other
			bits - i.e., pins - will be ignored).

SEE ALSO
     gpiobus(4), ow(4), ow_temp(4), owll(9), own(9)

LEGAL
     1-Wire is a registered trademark of Maxim Integrated Products, Inc.

HISTORY
     The owc driver first appeared in FreeBSD 11.0.

AUTHORS
     The owc device driver and this manual page were written by Warner Losh.

CAVEATS
     The  gpio	driver implements timing by busy waiting, which can cause a high
     load on slower systems.

BUGS
     Overdrive mode has not actually been tested.

FreeBSD 15.1			  June 26, 2019 			  OWC(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=owc&sektion=4&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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