PWM - Revision history

JulienB: /* Usage */

2022-02-10T11:30:35Z

Usage

← Older revision		Revision as of 13:30, 10 February 2022
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	imx-pwm imx-pwm.0: initialized		imx-pwm imx-pwm.0: initialized
	</pre>		</pre>
	* On [[APF28]] with 2.6.35 kernel and on [[APF6]], the PWM driver is builtin so no need to load it before use.		* On [[APF28]] with 2.6.35 kernel and on [[APF6]] & [[OPOS6UL]], the PWM driver is builtin so no need to load it before use.
	* For the one who plan to use sound, ''/dev/pwm0'' device file should be automatically created.		* For the one who plan to use sound, ''/dev/pwm0'' device file should be automatically created.

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	\|\|<pre class="apf">		\|\|<pre class="apf">
	export PWM_CHIP=pwmchip2 (on APF6Dev)		export PWM_CHIP=pwmchip2 (on APF6Dev)
	export PWM_CHIP=pwmchip0 (on APF9328Dev/APF27Dev/APF51Dev/APF28Dev)		export PWM_CHIP=pwmchip0 (on APF9328Dev/APF27Dev/APF51Dev/APF28Dev/OPOS6UL)

	export PWM=0 (on APF9328Dev/APF27Dev/APF51Dev/APF6Dev)		export PWM=0 (on APF9328Dev/APF27Dev/APF51Dev/APF6Dev/OPOS6UL)
	export PWM=4 (on APF28Dev)		export PWM=4 (on APF28Dev)
	</pre>		</pre>
	* declare the PWM we will use:		* declare the PWM we will use:
	<pre class="apf">		<pre class="apf">
	# echo $PWM > /sys/class/pwm/$PWM_CHIP/export		# echo ${PWM} > /sys/class/pwm/${PWM_CHIP}/export
	</pre>		</pre>
	* to have a 100uS period:		* to have a 100uS period:
	<pre class="apf">		<pre class="apf">
	# echo 100000 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/period		# echo 100000 > /sys/class/pwm/${PWM_CHIP}/pwm${PWM}/period
	</pre>		</pre>
	* to change duty cycle (for example 50% = 50us of 100us period)		* to change duty cycle (for example 50% = 50us of 100us period)
	<pre class="apf">		<pre class="apf">
	# echo 50000 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/duty_cycle		# echo 50000 > /sys/class/pwm/${PWM_CHIP}/pwm${PWM}/duty_cycle
	</pre>		</pre>
	* to activate PWM:		* to activate PWM:
	<pre class="apf">		<pre class="apf">
	# echo 1 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/enable		# echo 1 > /sys/class/pwm/${PWM_CHIP}/pwm${PWM}/enable
	</pre>		</pre>
	* to de-activate PWM:		* to de-activate PWM:
	<pre class="apf">		<pre class="apf">
	# echo 0 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/enable		# echo 0 > /sys/class/pwm/${PWM_CHIP}/pwm${PWM}/enable
	</pre>		</pre>

JulienB: /* Linux driver installation */

2016-04-15T16:21:09Z

Linux driver installation

← Older revision		Revision as of 18:21, 15 April 2016
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	i.MX PWM driver is installed by default in standard Armadeus rootfs.		i.MX PWM driver is installed by default in standard Armadeus rootfs.
	{{Note\|On [[APF51Dev]], as PWM outputs/pins are multiplexed and used as user LED and button by default, you may have to define APF51DEV_USE_LED_AS_PWM or APF51DEV_USE_SWITCH_AS_PWM in Linux sources (''arch/arm/mach-mx5/apf51dev-baseboard.c''), rebuild and reflash the Linux kernel.}}		{{Note\|On [[APF51Dev]], as PWM outputs/pins are multiplexed and used as user LED and button by default, you may have to define APF51DEV_USE_LED_AS_PWM or APF51DEV_USE_SWITCH_AS_PWM in Linux sources (''arch/arm/mach-mx5/apf51dev-baseboard.c''), rebuild and reflash the Linux kernel.}}

			{{Note\|On [[APF6Dev]], as PWM outputs is by default used for LCD's backlight control, you may have to modify APF6Dev device tree in Linux sources (''arch/arm/boot/dts/imx6qdl-apf6dev.dtsi''), rebuild and reflash the imx6q-apf6dev.dtb file.}}

	== Usage ==		== Usage ==

JulienB: /* Linux driver installation */

2016-04-15T14:50:23Z

Linux driver installation

← Older revision		Revision as of 16:50, 15 April 2016
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	== Linux driver installation ==		== Linux driver installation ==
	i.MX PWM driver is installed by default in standard Armadeus rootfs.		i.MX PWM driver is installed by default in standard Armadeus rootfs.
	{{Note\|On [[APF51Dev]], as PWM outputs are multiplexed and used as user LED and button by default, you may have to define APF51DEV_USE_LED_AS_PWM or APF51DEV_USE_SWITCH_AS_PWM in Linux sources (''arch/arm/mach-mx5/apf51dev-baseboard.c''), rebuild and reflash the Linux kernel.}}		{{Note\|On [[APF51Dev]], as PWM outputs/pins are multiplexed and used as user LED and button by default, you may have to define APF51DEV_USE_LED_AS_PWM or APF51DEV_USE_SWITCH_AS_PWM in Linux sources (''arch/arm/mach-mx5/apf51dev-baseboard.c''), rebuild and reflash the Linux kernel.}}

	== Usage ==		== Usage ==

JulienB: /* Hardware */

2016-04-15T14:49:48Z

Hardware

← Older revision		Revision as of 16:49, 15 April 2016
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	==Hardware==		==Hardware==
	PWM pin detail for each APF boards can be found [[Hardware\|here]] (under 'BaseBoards' section).		PWM pin detail for each APF boards can be found [[Hardware\|here]] (under 'BaseBoards' section).
	On [[APF28Dev]] for example, PWM4 is on J10 pin 26.		On [[APF28Dev]] for example, PWM4 is on connector J10 at pin 26.

	== Linux driver installation ==		== Linux driver installation ==

JulienB: /* PWM Mode */

2015-05-21T10:34:15Z

PWM Mode

← Older revision		Revision as of 12:34, 21 May 2015
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	\|\|<pre class="apf">		\|\|<pre class="apf">
	export PWM=0 (on ~~APF9328~~/~~APF27~~/~~APF51~~)		export PWM_CHIP=pwmchip2 (on APF6Dev)
			export PWM_CHIP=pwmchip0 (on APF9328Dev/APF27Dev/APF51Dev/APF28Dev)

			export PWM=0 (on APF9328Dev/APF27Dev/APF51Dev/APF6Dev)
	export PWM=4 (on APF28Dev)		export PWM=4 (on APF28Dev)
	</pre>		</pre>
	* declare the PWM we will use:		* declare the PWM we will use:
	<pre class="apf">		<pre class="apf">
	# echo $PWM > /sys/class/pwm/~~pwmchip0~~/export		# echo $PWM > /sys/class/pwm/$PWM_CHIP/export
	</pre>		</pre>
	* to have a 100uS period:		* to have a 100uS period:
	<pre class="apf">		<pre class="apf">
	# echo 100000 > /sys/class/pwm/~~pwmchip0~~/pwm$PWM/period		# echo 100000 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/period
	</pre>		</pre>
	* to change duty cycle (for example 50% = 50us of 100us period)		* to change duty cycle (for example 50% = 50us of 100us period)
	<pre class="apf">		<pre class="apf">
	# echo 50000 > /sys/class/pwm/~~pwmchip0~~/pwm$PWM/duty_cycle		# echo 50000 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/duty_cycle
	</pre>		</pre>
	* to activate PWM:		* to activate PWM:
	<pre class="apf">		<pre class="apf">
	# echo 1 > /sys/class/pwm/~~pwmchip0~~/pwm$PWM/enable		# echo 1 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/enable
	</pre>		</pre>
	* to de-activate PWM:		* to de-activate PWM:
	<pre class="apf">		<pre class="apf">
	# echo 0 > /sys/class/pwm/~~pwmchip0~~/pwm$PWM/enable		# echo 0 > /sys/class/pwm/$PWM_CHIP/pwm$PWM/enable
	</pre>		</pre>

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	</source>		</source>

			* Other test script may be found in ''target/test/test_pwm.sh'' of your armadeus BSP

	=== Audio Mode ===		=== Audio Mode ===

JulienB: /* Usage */

2015-05-21T10:25:18Z

Usage

← Older revision		Revision as of 12:25, 21 May 2015
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	imx-pwm imx-pwm.0: initialized		imx-pwm imx-pwm.0: initialized
	</pre>		</pre>
	* On [[APF28]] with 2.6.35 kernel, the PWM driver is builtin so no need to load it before use.		* On [[APF28]] with 2.6.35 kernel and on [[APF6]], the PWM driver is builtin so no need to load it before use.
	* For the one who plan to use sound, ''/dev/pwm0'' device file should be automatically created.		* For the one who plan to use sound, ''/dev/pwm0'' device file should be automatically created.

JulienB: /* Bash test script */

2015-02-17T15:23:53Z

Bash test script

← Older revision		Revision as of 17:23, 17 February 2015
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	\|}		\|}

	==== Bash test script ====		==== Bash test script (2.6 kernels) ====
	* A Bash test script is available given below. Just enter the desired frequency and duty cycle.		* A Bash test script is available given below. Just enter the desired frequency and duty cycle.
	<source lang="Bash">		<source lang="Bash">

JulienB at 15:22, 17 February 2015

2015-02-17T15:22:40Z

← Older revision		Revision as of 17:22, 17 February 2015
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	On this page, you will find usefull informations to configure and use the Pulse Width Modulation (PWM) capabilities of your APF boards.		On this page, you will find usefull informations to configure and use the Pulse Width Modulation (PWM) capabilities of your APF boards.

	The i.MX ~~processor is capable~~ of ~~driving 2~~ PWM signals:		The i.MX processors are able to drive 2 types of PWM signals:
	* one is linked to the LCD controller and allows ~~controling~~ the [[BackLight \| LCD backlight]] (fixed frequency)		* one that is linked to the LCD controller and allows controlling the [[BackLight \| LCD backlight]] (fixed frequency)
	* the other can be used to generate a PWM signal in several mode:		* the other can be used to generate a PWM signal in several mode:
	** audio playback		** audio playback

JulienB: /* 2.6 kernel */

2015-02-17T15:21:28Z

2.6 kernel

@@ Line 31: / Line 31: @@
 After driver loading, you have access to ''/sys/class/pwm/...'' functionalities:
-====2.6 kernel====
+{| border="1" cellpadding="10" cellspacing="0" summary="PWM usage depending on kernel version" class="wikitable"
-<pre class="apf">
+|- style="background:#efefef;" align="center"
 export PWM=pwm0    (on APF9328/APF27/APF51)
 export PWM=pwm4    (on APF28Dev)
@@ Line 56: / Line 60: @@
   # echo 0 > /sys/class/pwm/$PWM/active
 </pre>
 ==== Bash test script ====

JulienB: /* PWM Mode */

2015-02-17T14:49:21Z

PWM Mode

← Older revision		Revision as of 16:49, 17 February 2015
Line 30:		Line 30:

	After driver loading, you have access to ''/sys/class/pwm/...'' functionalities:		After driver loading, you have access to ''/sys/class/pwm/...'' functionalities:

			====2.6 kernel====
	<pre class="apf">		<pre class="apf">
	export PWM=pwm0 (on APF9328/APF27/APF51)		export PWM=pwm0 (on APF9328/APF27/APF51)