Change GPIO pin mode to ALT with Python RPi.GPIO

Question

I usually use RPi.GPIO module like this to set up the GPIO pins:

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(17, GPIO.IN, pull_up_down=GPIO.PUD_UP)

Is it possible to change mode of a pin to ALT5 like I would do with wiringpi's gpio tool :

> gpio -g mode 15 alt5 // sets GPIO 15 pin to ALT 5 mode

but with Python's RPi.GPIO ?

joan · Accepted Answer · 2015-04-05 13:30:20Z

1

No. As far as I am aware RPi.GPIO only supports modes INPUT and OUTPUT. Modes ALT0, ALT1, ALT2, ALT3, ALT4, and ALT5 are not supported.

answered Apr 5, 2015 at 13:30

joan

71.7k5 gold badges74 silver badges107 bronze badges

Ok! Is it me or the RPi.GPIO module documentation is really lacunar? No real exhaustive API, or maybe I looked at the wrong place? I'll do gpio -g mode 15 alt5 before my Python script begins then...
– Basj
Commented Apr 5, 2015 at 13:40
A linked issue: I am now able to set RXd (GPIO 15) to RX1 (ie a 2nd serial port). But I don't have /dev/ttyAMA1 , I only have /dev/ttyAMA0. Do you know how to create that second serial port @joan ?
– Basj
Commented Apr 5, 2015 at 13:41
@Basj No, sorry, I don't know how to create /dev/ttyAMA1. To what end though? You'll still only have one serial link, just with a different name, as it uses the same gpios. You'd need to have a compute module to get an additional serial port.
– joan
Commented Apr 5, 2015 at 13:52
Because @joan I want to use TX0 (ttyAMA0) for one thing (a 7segment display), and RX1 (ttyAMA1) for another thing (receive some MIDI IN!)... Therefore, I need 2 different half-ports (for the 7segment display, I only need TX, and for MIDI IN, I only need RX) with 2 different baud setting...
– Basj
Commented Apr 5, 2015 at 14:41
@Basj You should be able to do that with /dev/ttyAMA0 without any fuss. Open the port once for reading and again for writing. You can certainly set different input/output baud rates from C
– joan
Commented Apr 5, 2015 at 14:46

| Show 4 more comments

1 Answer 1