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)

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.