#96 GPIO.BOTH does not indicate which edge was triggered

[John Snow]

This was an issue on the google code tracker, but I don't see it here.

Further, using

:::python
def cb(pin):
    state = GPIO.input(pin)

to try to ascertain the state, seems to produce uncertain results (at least in my setup...)

For example; using an arcade button wired to connect ground to GPIO 23 when closed and using the PUD_UP option, I can generally see that GPIO.input(23) is 1 when the button is open, and 0 when the button is closed. OK.

Using the GPIO.BOTH callback with a bouncetime of around 5ms, I only get one callback on press, and one callback on release. OK.

However, if I try to get the state as noted above, on both press and release the state always seems to be '1' as if the button was open. If I re-read the input after a print statement (introducing some delay), the state reads as expected;

:::python
def cb2(pin):
    state = GPIO.input(pin)
    print "This is the wrong state: %s" % state
    state = GPIO.input(pin)
    print "This is the right state: %s" % state

GPIO.add_event_detect(23, GPIO.BOTH, callback=cb2, bouncetime=5)

I am not sure what the uncertainty is in reading the pins, but the callbacks are getting called when I want -- it'd be very nice if the callback just told you which event actually triggered it.

[Matthew Lewis]

I would also very much like this feature added. I believe there would be a race condition otherwise. I looked at migrating to the similar RPIO library which has this feature however it appears that that library has been discontinued.

[Ben Croston]

The fix will be done in conjunction with work on issue 121. I need to think how I can handle the edge type being returned to the callback function without breaking eveyone's existing code.