dey-examples/apix-pwm-example

Digi APIX PWM Sample Application

Sample application to access and manage PWM lines using the Digi APIX library.

The application enables one PWM line of the board using a frequency of 1000Hz. Then, progressively modifies the duty cycle in a loop from 10% to 90% and vice-versa.

The PWM lines used in the sample are mapped as follows in the Digi Boards:

• CCIMX6 SBC: PWM1 - Pin 10 of the parallel video (LCD) connector.
• CCIMX6UL SBC Express: PWM1 - Pin 27 of the expansion connector.
• CCIMX6UL SBC Pro: PWM4 - Pin 11 of the GPIO connector.

The following device tree modifications are required for the sample to work:

• CCIMX6 SBC:

/* PWM1 */
&pwm1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_pwm1>;
	status = "okay";
};

/* Pin mux configuration */
&iomuxc {
	imx6q-ccimx6sbc {
		pinctrl_pwm1: pwm1grp {
			fsl,pins = <
				MX6QDL_PAD_DISP0_DAT8__PWM1_OUT 0x110b0
			>;
		};
	};
};

• CCIMX6UL SBC Express: No device tree modifications are required.
• CCIMX6UL SBC Pro:

/* PWM4 */
&pwm4 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_pwm4>;
	clocks = <&clks IMX6UL_CLK_PWM4>,
		<&clks IMX6UL_CLK_PWM4>;
	status = "okay";
};

/* Pin mux configuration */
&iomuxc {
	imx6ul-ccimx6ul {
		pinctrl_pwm4: pwm4grp {
			fsl,pins = <
				MX6UL_PAD_GPIO1_IO05__PWM4_OUT    0x110b0
			>;
		};
	};
};

Running the application

Once the binary is in the target, launch the application:

#> pwm-digiapix-sample

The sample applicaion is ready to work with all Digi platforms using the corresponding PWM chip (0 by default) and a frequency of 1000Hz. If a different PWM chip or frequency is required, the application allows 2 additional parameters in order to customize these values:

#> pwm-digiapix-sample [pwm-chip pwm-freq]

Where:

• 'pwm-chip' is an optional PWM chip number.
• 'pwm-freq' is an optional frequency to use (Hz).

Compiling the application

This demo can be compiled using a Digi Embedded Yocto based toolchain. Make sure to source the corresponding toolchain of the platform you are using, e.g:

$> . <DEY-toolchain-path>/environment-setup-cortexa7hf-vfp-neon-dey-linux-gnueabi
$> make

More information about Digi Embedded Yocto.

License

Copyright 2017, Digi International Inc.

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.