Allwinner R329 development board lighting tutorial

aleksib

Allwinner R329 development board lighting tutorial [Copy link]

 

# Lighting etc. After successfully connecting the development board with the serial port or ADB, you can control the development board through terminal commands. Next, we will introduce several modules encapsulated in the Tina Linux system. You can start the demo of these modules through commands and control the software and hardware of several modules in the terminal. First, it is a compulsory course in our university microcontroller course: Lighting R329 supports LEDC. The full name of LEDC is ** "Light Emitting Diode Controller" **. It is an LED control module implemented with the help of the Linux LED standard subsystem. It can light up, adjust the brightness, flash, and control the array of LED lights. The LEDC module is used a lot on screenless smart speakers. For example, in scenes such as waiting for pairing, waking up, and music playing, the LED light will indicate the current state with different effects. The built-in firmware has compiled the LEDC module, which can directly control the LED node to light up the LED light. ## Enter the LED light path First, we can enter the location of the LED node to view the three color nodes of an LED light (RGB): ```bash root@TinaLinux:/# cd /sys/class/leds/ root@TinaLinux:/sys/class/leds# ls sunxi_led0b sunxi_led0g sunxi_led0r ```  ## View the configuration of the LED light. The three nodes represent three colors respectively. We can enter a color node, such as red (R): ```bash root@TinaLinux:/sys/class/leds# cd sunxi_led0r/ root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# ls brightness device subsystem delay_off max_brightness trigger delay_on power uevent ```  You can see that LEDC has done a lot of basic operations of LEDC, including brightness adjustment, flashing, delay, etc. ## Turn on a light If we want to light up one of the colors, we can write the brightness value to **brightness**. The maximum brightness value is 255: ```bash root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# echo 255 > brightness ``` At this time, the LED light will be turned on ## Adjust brightness If you want to adjust the brightness value, just adjust the value written to **brightness**. The brightness value range is 0~255, 0 represents off, and 255 represents the brightest: ```bash root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# echo 255 > brightness root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# echo 100 > brightness root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# echo 10 > brightness root@TinaLinux:/sys/devices/platform/soc/ledc/leds/sunxi_led0r# echo 0 > brightness ```   ## Turn on lights of other colors If you want to light up lights of other colors, just refer to the red light and write the brightness value to the **brightness ** of the green and blue lights: ````bash root@TinaLinux:/sys/class/leds# echo 255 > sunxi_led0g/brightness root@TinaLinux:/sys/class/leds# echo 0 > sunxi_led0g/brightness root@TinaLinux:/sys/class/leds# echo 255 > sunxi_led0b/brightness root@TinaLinux:/sys/class/leds# echo 0 > sunxi_led0b/brightness ````   ## Flashing If you want to achieve the effect of LED flashing, just write **timer** to **trigger**: ```bash root@TinaLinux:/sys/class/leds# echo timer > sunxi_led0r/trigger ``` **If you see the light is on, then congratulations, it will illuminate your path of embedded development learning. ** For advanced operations such as LED array operation, module configuration, source code structure, internal and external interfaces, please refer to the development document "Tina Linux LED Development Guide" At the same time, you can also use three PWM interfaces to control the three-color LED lights, but it takes up more pins and resources.

吾妻思萌

I was saying, why are all the lights on? It turns out that they are lighting the way forward.

LitchiCheng

Maybe smoke testing is also necessary, a man’s first “electronic cigarette”