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PWM(8)			     System Manager's Manual			  PWM(8)

NAME
     pwm -- configure PWM (Pulse Width Modulation) hardware

SYNOPSIS
     pwm [-f device] -C
     pwm [-f device] [-D | -E] [-I] [-p period] [-d duty]

DESCRIPTION
     The  pwm utility can be used to configure pwm hardware.  pwm uses a pwmc(4)
     device to communicate with the hardware.  Some PWM hardware supports multi-
     ple output channels within a single controller block; each pwmc(4) instance
     controls a single PWM channel.

     pwmc(4) devices are named /dev/pwm/pwmcX.Y, where X is the controller  unit
     number and Y is the channel number within that unit.

     The options are as follows:

     -f device	Device	to  operate  on.   If not specified, /dev/pwm/pwmc0.0 is
		used.  If an unqualified name is provided, /dev/pwm is automati-
		cally prepended.

     -C 	Show the configuration of the PWM channel.

     -D 	Disable the PWM channel.

     -d duty	Configure the duty cycle (in nanoseconds or percentage)  of  the
		PWM channel.  Duty is the portion of the period during which the
		signal is asserted.

     -E 	Enable the PWM channel.

     -p period	Configure the period (in nanoseconds) of the PWM channel.

     -I 	Invert PWM signal polarity

EXAMPLES
     *	 Show the configuration of the PWM channel:

	 pwm -f /dev/pwm/pwmc0.1 -C

     *	 Configure  a  50000  ns period and a 25000 ns duty cycle and enable the
	 channel:

	 pwm -f pwmc1.1 -E -p 50000 -d 25000

     *	 Configure a 50% duty cycle on the device and channel which were config-
	 ured in pwmc(4) to have the label backlight:

	 pwm -f backlight -d 50%

SEE ALSO
     pwm(9), pwmbus(9)

HISTORY
     The pwm utility appeared in FreeBSD 13.0.

AUTHORS
     The pwm utility and  this	manual	page  were  written  by  Emmanuel  Vadot
     <manu@FreeBSD.org>.

FreeBSD ports 15.quarterly	  June 17, 2019 			  PWM(8)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=pwm&sektion=8&manpath=FreeBSD+15.1-RELEASE+and+Ports.quarterly>

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