Need clear understanding about CAF example project

[akay47]

I am working on nrf52840 and using v2.7.0 SDK. in led_state_def.h (i modified it a little)

static const struct led_effect led_effect[] = {

    [LED_EFFECT_ID_OFF] = LED_EFFECT_LED_OFF(),

    [LED_EFFECT_ID_BLINK] = LED_EFFECT_LED_BLINK(2000, LED_COLOR(10, 255, 10)),

    [LED_EFFECT_ID_BREATH] = LED_EFFECT_LED_BREATH(2000, LED_COLOR(255, 255, 255)),

    [LED_EFFECT_ID_CLOCK] = LED_EFFECT_LED_CLOCK(3, LED_COLOR(255, 255, 255)),

    [LED_EFFECT_ID_BLINK_SLOW] = LED_EFFECT_LED_BLINK(10000, LED_COLOR(255,255,255)),

    [LED_EFFECT_ID_BLINK_FAST] = LED_EFFECT_LED_BLINK(50, LED_COLOR(255,255,255))

};

I dont understand the role of LED_COLOR() here. Seems like it is for RGB Led but for dev kit we have single color led. i am kind of confused because in this example overlay file have 4 pwm pins so why each pin has its own individual LED_COLOR() with 3 values. Should not it has only one value maybe telling duty cycle between 0-255 for a single pin? How is it working?

What if i want to use this program with RGB LED, i understand i can connect 3 pwm0-2 given in overlay to R, G, B of my tri color led , but again why 3 different values for each pin in LED_COLOR()?

Thanks.

[Edvin]

Hello,

I think you should study the application sample in:

NCS\nrf\applications\nrf_desktop

And look there how it is used. But again, I am not convinced that this is the easiest way to control some RGB leds. 

If you look at how the led_state_def.h is being used in led_state.c (ncs\nrf\samples\caf\src\modules\led_state.c), these gpios are set in the file:

nrf\samples\caf\boards\<board_name>.overlay, and the pwmleds1, pwmleds2 and pwmleds3, which I believe is what you are asking.

Best regards,

Edvin

[akay47]

Thanks, i got some idea and i was able to understand how this example works with CAF LED as PWM. But now there is an option to change LED PWM to LED GPIO. after doing that i am not sure what all changes overlay file would need for this LED GPIO CAF. Here is my sample but it does not work at all: 

 / {

    gpio_leds {

        compatible = "gpio-leds";

        status = "okay";

        led4: led_4 {

            gpios = <&gpio1 2 GPIO_ACTIVE_LOW>;

            label = "LED 4";

        };

        led5: led_5 {

            gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;

            label = "LED 5";

        };

        led6: led_6 {

            gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;

            label = "LED 6";

        };

    };

};

&gpio0 {

    status = "okay";

};

&gpio1 {

    status = "okay";

};

Then i debug the code and in leds.c file led[] has no instance of gpios that i setup. Any idea on this? thanks

[Edvin]

Did you do any changes to the leds.c file?

Did you define CONFIG_CAF_LEDS_GPIO=y in your prj.conf?

Best regards,

Edvin