Inputs won't work using 0x06, you need to select the proper pinmux
setting *AND* enable the input buffer.  Also, with the provided device
tree it is still necessary to reboot if you want to change anything.

I have a universal device tree (available pre-installed on current
Debian based BeagleBone images) that allows dynamic reconfiguration of
the I/O pins without rebooting.  Simply use the config-pin utility to
setup the I/O pins as needed:

config-pin -a P8.15 pruin    # The -a automatically loads the overlay
config-pin P8.20 pruout

Once the overlay is loaded you can reconfigure the pin muxing as much as
needed without having to reboot.

On 5/19/2014 7:41 AM, Florian Hänel wrote:
> Here's a dts file that works for me for r30/31
> You can comment out or in pins you need or don't need.
> 
> All pins are configured for r30 (output), to use r31 (input) change the
> 0x05 to 0x06 respectively.
> 
> Note that this uses pins used by hdmi/lcd and mmc1 (the onboard emmc of
> the BBB).
> You need to disable the capes for these first if you want to use these
> pins as well:
> http://www.logicsupply.com/blog/2013/07/18/disabling-the-beaglebone-black-hdmi-cape/
> 
> I tested all pins with my oscilloscope, they appear to work in this
> configuration.
> 
> Florian
> 
> 
> On 19.05.2014 07:08, foreverska wrote:
>> Has anyone used the Pin Mux Utility?  I'm trying to enable R30 and R31
>> on my PRUs.  I've had a rough time enabling device trees so I decided
>> to try and use the Pin Mux Utility.  It seems relatively easy to use
>> and it produces nice .h files but the compiler has an issue with some
>> of the code.
>>
>> |
>> #define MUX_VAL(OFFSET,VALUE)\
>>     writel((VALUE), AM335X_CTRL_BASE + (OFFSET));
>> |
>>
>> Neither GCC or G++ know what to make of writel().  They say it's not
>> defined and such.  I've read something about linux/io.h but I haven't
>> been able to find it.  Am I barking up a tree with this utility?
>>
>> Those who have successfully done Pin Muxing, by what means?  I've
>> tried doing the hipster circuit tutorial but debian doesn't like the
>> tree so says dmesg.  I'm not sold on the tree method anyways because I
>> wouldn't mind being able to alter the muxing between compiles not
>> restarts.

-- 
Charles Steinkuehler
[email protected]

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