Assigning priority to callback function for multiple GPIO.add_event_detect

Question

Iam trying to create the error detection application for my battery charger prototype using Rpi.GPIO. I successfully created the add event detect for multiple GPIO pins (totally 8 pins for each error).

My doubt is regarding the assignment of priority for each error. I try to run the call back function depends on the priority list below but unsuccessful. If i give emergency stop signal after earth missing it is not detected. Emergency stop signal gets detected only after earth missing signal. I listed the error according to the priority below.

1. Emergency stop
2. Phase reversal
3. Earth Leakage
4. Earth Missing
5. Short circuit
6. power failure
7. Input over voltage
8. Input under voltage

I attached the example code below

import RPi.GPIO as GPIO
from time import sleep

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # We are accessing GPIOs according to their physical location
GPIO.setup(37, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(35, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(33, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(31, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(29, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(40, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(38, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(36, GPIO.IN, pull_up_down=GPIO.PUD_UP)

def errorDetection(channel):
    if(channel == 37):
        while GPIO.input(37) == 0:
            print('Emergency stop occured')
                 
                
    elif(channel ==  35):
        while GPIO.input(35) == 0:
            print('Phase reverse occured')
                
    elif(channel == 33):
        while GPIO.input(33) == 0:
            print('Earth leakage occured')
               
    elif(channel == 31):
        while GPIO.input(31) == 0:
            print('Earth Missing occured')
                
    elif(channel == 29):
        while GPIO.input(29) == 0:
            print('Short circuit occured')
        
    elif(channel == 40):
        while GPIO.input(40) == 0:
            print('Power failure occured')
        
    elif(channel == 38):
        while GPIO.input(38) == 0:
            print('Input over voltage occured')
        
    elif(channel == 36):
        while GPIO.input(36) == 0:
            print('Input under voltage occured')
        
GPIO.add_event_detect(37, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(35, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(33, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(31, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(29, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(40, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(38, GPIO.FALLING, errorDetection, bouncetime=2000)
GPIO.add_event_detect(36, GPIO.FALLING, errorDetection, bouncetime=2000)

i = 0;
while i <= 10:
    print("i value",i)
    i = i+1
    sleep(4)
    if i == 10:
        i = 0

Answer 1

You have a while loop for each condition. That means the program flow stops at that position until the condition is removed.

I suggest you change those while to if. That should do what you seem to want.

E.g. rather than

while GPIO.input(37) == 0:

use

if GPIO.input(37) == 0: