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OWC(4)			 BSD 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 configure 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.

BSD				 June 26, 2019				   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | LEGAL | HISTORY | AUTHORS | CAVEATS | BUGS

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