bionic (4) owc.4freebsd.gz

Provided by: freebsd-manpages_11.1-3_all bug

NAME
     owc — Dallas Semiconductor 1-Wire Controller


SYNOPSIS
     device owc


DESCRIPTION
     The owc module implements Dallas Semiconductor 1-Wire signaling.  It attaches 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/boot/fdt/dts/bindings-gpio.txt.


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


     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.