Rpi GPIO 40 warning channel is busy

Question

When I try to toggle the Raspi pin no 40 using the code it gives me message

RuntimeWarning : The channel is already in use, continuing anways and asks to disable warnings. Even after doing GPIO.setwarnings(False), the warning doesn't pop but the port does not toggle at all. I had tested the RPI.GPIO library quite a while ago their was no problem, in toggling the ports.

#! /usr/bin/python

import array
import os
import time
import RPi.GPIO as GPIO

def main():

    GPIO.setmode(GPIO.BCM)
    GPIO.setup(40,GPIO.OUT)
    time.sleep(1)
    while True:

        GPIO.output(40,GPIO.HIGH)
        time.sleep(5)
        GPIO.output(40,GPIO.LOW)
        time.sleep(5)

if __name__=='__main__':
    try:
        main()
    except KeyboardInterrupt:
        spi.close()
        GPIO.cleanup()
    finally:
        GPIO.cleanup()

Answer 1

Unless you are using a compute module you will have no access to Broadcom gpio 40 (I'm not even sure if RPi.GPIO will run on the compute module).

You probably mean to use pin 40 which is gpio21. Either use 21 in your code or change GPIO.setmode(GPIO.BCM) to GPIO.setmode(GPIO.BOARD).

GPIO.setmode(GPIO.BCM) says to use Broadcom gpio numbering.

GPIO.setmode(GPIO.BOARD) says to use pin numbering.

---

Pins and gpios

           pin  pin
3V3         1    2      5V
0/2 (SDA)   3    4      5V
1/3 (SCL)   5    6      0V
4           7    8      14 (TXD)
0V          9   10      15 (RXD)
17 (ce1)   11   12      18 (ce0)
21/27      13   14      0V
22         15   16      23
3V3        17   18      24
10 (MOSI)  19   20      0V
9 (MISO)   21   22      25
11 (SCLK)  23   24      8 (CE0)
0V         25   26      7 (CE1)
           .......
0 (ID_SD)  27   28      1 (ID_SC)
5          29   30      0V
6          31   32      12
13         33   34      0V
19 (miso)  35   36      16 (ce2)
26         37   38      20 (mosi)
0V         39   40      21 (sclk)