GPiO

Yes.

Additionally, if you use the gpio command (part of wiringPi) to load the i2c kernel module then it changes ownership to that of the calling user.

You can - I think the foundation has changed group ownership to 'gpio' which makes it easier, but I think you still need to be root to setup the actual export via the /sys/class/gpio interface. Again wiringPi's gpio command will make this easy for you.

It runs as a set-uid root program, so you can run it from the command-line or in scripts without using sudo ..

The down-side of using the sysfs interface is thats it's not that fast - fine for simple stuff though.

Gordon

I have already set this up manually (Working fine) but may be useful for others.

Speed is not an issue, I just don't want code running a root if it is not needed.

wiringPI looks like it needs downloading as source & compiling, is there a simpler option (I am not opposed to building software if necessary but would prefer to keep to the standard repositories if possible)

Cheers for the info so far.

I probably should have added I will be programming in python. after years of 8 bit assembler programming I don't want to get involved in all that low level stuff again.

This is what we wrote in the PIF

Provided you have /etc/modprobe.d/raspi-blacklist.conf, you will need to remove the I2C and SPI blacklisting. Start up an editor, for instance nano:

sudo nano /etc/modprobe.d/raspi-blacklist.conf

then comment out these lines by putting a # at the start of each line:

blacklist spi-bcm2708 blacklist i2c-bcm2708

Add the I2C kernel modules by editing /etc/modules:

sudo nano /etc/modules

and insert two lines at the end of the file:

i2c-bcm2708 i2c-dev

then reboot (sudo reboot).

Download the i2ctools utility:

sudo apt-get install python-smbus sudo apt-get install i2c-tools

and check that the ... board is visible:

sudo i2cdetect -y 1

It's in the works as it were - so it'll be in the repositories in a week or 2, hopefully.

wiringPi is a C library for C/C++ programs. I don't consider it particularly low-level.

// blink.c:

#include main () { wiringPiSetup () ; pinMode (0, OUTPUT) ; for (;;) { digitalWrite (0, 1) ; delay (500) ; digitalWrite (0, 0) ; delay (500) ; } }

The gpio command is a command-line swiss army knife type utility for all the Pi's GPIO. It started life as the wiringPi test program then because usefull - I've written projects in bash using it... (and been horrified to see people using it via system() from C, Python, PHP, and even my BASIC which has it built in...

#!/bin/bash

gpio mode 0 out while true; do gpio write 0 1 ; sleep 0.5 gpio write 0 0 ; sleep 0.5 done

You probably want RPi.GPIO for your Python code.

Gordon

As i said I have already done this for the i2c the question was could the same be done for the GPIO so far Gordon has given me a good start by suggesting wiringPI.

Yep, I read the question too quickly. Apologies.

Tim

silly question If i build wiringPi on my shiny new fast 2B will it run on my old rev 1 model B?

Yes.

And if you use wiringPi pin numbers you don't need to wory about the pin 22->27 change either. (Nor the I2C interface)

Gordon