I am using my raspberry pi 3 to run some services. When someone powers on the Raspberry I want to use RGB LEDs to indicate the status instead of using a LCD screen to output messages. The LEDs I plan on using are digital meaning I can turn the first LED green the second red and so on unlike a analog LED strip where you turn on all the lights at the same time with the same color. This video illustrates a digital led strip connected to a raspberry pi 3 https://youtu.be/zlpjlY_MfeA
Before continuating with the question:
Is the input/signal from the first diagram (LED strip that I got) a PWM signal? I assume it is otherwise I have to rephrase the title of this question. This confuses me because the LED strip is digital and PWM is analog? Moreover there are other digital LED strips that have 4 pins like this one: Does that digital LED strip uses PWM as well? Sorry I am new to the embedded world I am probably wrong on this.
Back to the question:
There are lots of tutorials on the internet on how to turn on digital LED strips such as this amazing one: https://tutorials-raspberrypi.com/connect-control-raspberry-pi-ws2812-rgb-led-strips/ . But none of them show how to do this at boot time or maybe I have not searched enough.
So my question is how can I do this at boot time? All this tutorials show you how to do it once your raspberry pi boots (after /etc/rc.local). The reason why I want to use the LED strip is to show the status of the raspberry pi. When it is booting I will like to show the LEDs flashing with yellow for example. The board takes 14 seconds to boot and the LEDs are off until the pi boots. I do not want to wait 14 seconds to show the status. I just want to send a constant PWM signal throughout a GPIO pin on my raspberry and once the computer boots I could change that signal