Operating 2 Gpio pins at same time

Question

I want to write a program that can operate 2 gpio pins with different ON-OFF times at same time.

Say the time duration is 2 sec. In this time duration, I want to set GPIO 4 HIGH for 1 sec and LOW for 1 sec. And in that 2-sec same duration, I want to set GPIO 5 HIGH for 0.5 sec and LOW for 1.5 sec. I am not getting the logic on how to do this.

Answer 1

Maintain a list of GPIO event times, e.g. a list containing a GPIO number, a time, and a new level for the GPIO.

GPIO Time Level
23   10.0   1
23   14.0   0
15   15.4   1
23   16.2   1
15   17.4   0
23   20.2   0

Run a main loop which executes regularly, say 10 times a second. Check if events are due. If any are process the event and then sleep for the loop period.

while true
   now = current_time
   for each event
      if now >= event.Time
         set GPIO event.GPIO to level event.Level
         delete event
   sleep(0.1)