Unable to use GPIO04/Pin7 as Interrupt?

[projectcornholio]

Hey guys,

I've been working hard on learning how to use and interface with the pi! It's been great so far but I've been unable to get past this issue on my own. I've done online research but can't find anything...

So I'm working on a larger project but in an effort to troubleshoot the issue, I've written a little code to demonstrate the issue. I keep getting the error:

GPIO.add_event_detect(4, GPIO.FALLING, callback=buttonpressed, bouncetime=300)
RuntimeError: Failed to add edge detection

I realise that GPIO04/Pin7 is the GCLK so that could be the issue but I need a way around it because my project is currently using all other available pins (except pins 27 and 28). Below is my code that returns this error.

Please help! Any response is appreciated!

All I'm needing is for the button to interrupt the main thread, do its own thing and then resume the main thread.

Code: Select all

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

def buttonpressed(channel):
    print("\n")
    print('Button Was Pressed')

GPIO.add_event_detect(4, GPIO.FALLING, callback=buttonpressed, bouncetime=300)

while 1:
    print('waiting...')
    time.sleep(1)
    

[mattmiller]

The problem is that your using a pull-down resistor AND looking for a falling edge

Since the input is low - then it can't fall any further

[projectcornholio]

Thanks for the response and good catch! That was a stupid typo on my end. Sadly, this didn't fix the issue though.

I have re-written the code to be more generic and pasted it below. I do hope that I'm making some mistake that I continuously overlook. I get the same error as before:

GPIO.add_event_detect(7, GPIO.RISING, callback=my_callback)
RuntimeError: Failed to add edge detection

Code: Select all

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BOARD)

## Pin 7 is going to 3.3 PWR through the button

GPIO.setup(7, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)



def my_callback(channel):
    print("\n")
    print('Button Was Pressed')

GPIO.add_event_detect(7, GPIO.RISING, callback=my_callback)


try:
    while 1:
        print('waiting...')
        time.sleep(1)

except KeyboardInterrupt:  
    GPIO.cleanup()

[joan]

Works for me.

Code: Select all

$ python q.py
waiting...
waiting...


Button Was Pressed


Button Was Pressed
waiting...
waiting...


Button Was Pressed
waiting...
waiting...
^C$ 

[projectcornholio]

Well... that's confusing. So maybe it's board related? Do you guys think it's hardware? I can try testing pin7 to make sure it still goes high and low properly. Maybe give the board an update and keep my fingers crossed?

[mattmiller]

Its quite easy (unless hardwired while power is off) to accidentally connect to pin2 instead of pin1 (Done it twice myself)

I now ALWAYS enable pull-ups and connect the other end of switches to gnd

[B.Goode]

Maybe give the board an update

The hardware of an RPi board cannot be updated. It contains no 'flash' or any other form of non-volatile persistent memory. Other than a very small number of bits - literally bits - of One Time Programmable configuration (OTP) your RPi cannot be modified from the way it left the factory.

[pcmanbob]

Code: Select all

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BOARD)

## Pin 7 is going to 3.3 PWR through the button

GPIO.setup(7, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

Check you have your switch connected to the right GPIO pin
it should be connected to pin 7 not GPIO 7 as you are using board mode

[joan]

Check your version of RPi.GPIO is up to date. Mine is 0.6.3 (GPIO.VERSION). It seems likely you are using an ancient version of the module.

[mattmiller]

It seems likely you are using an ancient version of the module

What's made you say that?

[joan]

It seems likely you are using an ancient version of the module

What's made you say that?

The error message.

GPIO.add_event_detect(7, GPIO.RISING, callback=my_callback)
RuntimeError: Failed to add edge detection

I don't know the condition used to raise the error but it sounds like a misconfiguration. Or perhaps the GPIO is shot, but I think it unlikely that Linux or RPi.GPIO would test for that possibility during GPIO initialisation.

[mattmiller]

The error message.

I completely missed that they were getting an error msg
Twice
Silly me!

[projectcornholio]

Thanks for the help guys. I just updated my Rpi.GPIO and it says its already up to date :/ See image attached.

[joan]

Thanks for the help guys. I just updated my Rpi.GPIO and it says its already up to date :/ See image attached.

What is given by print(GPIO.VERSION) ?

[morgannickraspi]

Panic ye not - there's probably nothing wrong with your PI. I had the exact same issue and it can be fixed by updating your PI to the latest version:

Code: Select all

sudo apt-get update
sudo apt-get dist-upgrade

Have fun!

[bensimmo]

DO NOT RUN rpi-update it is not a way to update the.
It is used for testing new stuff and fixes/things that might break it however.

[bensimmo]

One thing I will say is check you do not have 1-Wire enabled, as that will 'load up' on gpio4 (Pin7)

Check the simple code works by putting it on another pin for testing.

[DougieLawson]

Panic ye not - there's probably nothing wrong with your PI. I had the exact same issue and it can be fixed by updating your PI to the latest version:

Code: Select all

sudo apt-get update
sudo apt-get dist-upgrade
sudo rpi-update

Have fun!

There is no reason for general users to EVER run rpi-update. Please don't suggest it, it should be used ONLY when advised by an expert. Anyone who does run it MUST know how to rebuild their system when something bad goes wrong.

[morgannickraspi]

Apologies all if I've given bum info. Thanks for the rip-update heads up.

The update and dist-upgrade will fix "RuntimeError: Failed to add edge detection" problem though.

[quote="DougieLawson"][quote="morgannickraspi"]Panic ye not - there's probably nothing wrong with your PI. I had the exact same issue and it can be fixed by updating your PI to the latest version:

Code: Select all

sudo apt-get update
sudo apt-get dist-upgrade

Have fun!