Adding a 9th button to GPIO

theRog05

@edmaul69 I'm using arcade buttons (2 joysticks and 18 buttons), all which are connected to the GPIO of the pie. Each "controller" is using a Joystick along with buttons A, B, X, Y, LT, RT, select, start, hk (9th controller button). If you are familiar with Recalbox, they allow that 9th button to be used as a hotkey. I understand that I could use select for the hotkey, but I already built the cabinet and have that 9th button for each controller; I don't want it to go unused. Both of my hotkey buttons are connected to GPIO2 (PIN3) and GPIO3 (PIN5) on the pie (which is the suggested configuration for RecalBox. If it's possible for RecalBox, I would think it should be possible for Retropie, I just can't figure out where I would need to make a change to allow for this.

spruce_m00se

well if you cant figure it out just wire up two buttons to one gpio, then at least you have a working ninth button

theRog05

@spruce_m00se This would defeat the purpose of having another button to do something different. I would rather find out how to utilize the GPIO for another button.

simonster

You need to install the hotkeybtn variant of mk_arcade_joystick, this isn't installed by the RetroPie installer as it isn't part of the main branch, but can be done manually from the command line. The instructions aren't clear on their git page, but I think this is the correct order.

git clone https://github.com/pinuct/mk_arcade_joystick_rpi/tree/customgpiohotkey
mkdir /usr/src/mk_arcade_joystick_rpi-0.1.5/
cd mk_arcade_joystick_rpi/
cp -a * /usr/src/mk_arcade_joystick_rpi-0.1.5/
dkms build -m mk_arcade_joystick_rpi -v 0.1.5
dkms install -m mk_arcade_joystick_rpi -v 0.1.5

Once you have done this and restarted, I think that you should be OK, as it will upgrade the version already installed.

The reference is on the git page: https://github.com/recalbox/mk_arcade_joystick_rpi/tree/hotkeybtn

theRog05

@simonster said in Adding a 9th button to GPIO:

You need to install the hotkeybtn variant of mk_arcade_joystick

Thanks!!! I'll give this a shot tonight or this weekend and let you know how it goes.

edmaul69

@theRog05 do both controllers have a 9th key or just one controller? If only one is it actually going to controller 1?here is something you could try. Set up the controller in emulationstation and choose select as your hotkey. Now open up /opt/retropie/configs/all/retroarch/autoconfig/NAMEOFYOURCONTROLLER.cfg and find the hotkey line and change it to the correct button number. I assume that would be 8. (Since buttons start with zero)

simonster

Hi @edmaul69 , the problem is the standard GPIO driver only has 8 buttons and 4 directions per pad (equivalent of a SNES pad), you can add a 9th but it requires a fork of the standard driver that removes I2C support whilst installed, it appears that they were previously using this when using Recalbox (as GPIO 3 and 5 are the correct wirings for this in the driver) but the version included in RetroPie is the main branch and doesn't include support for the 9th button.

theRog05

@edmaul69 : I actually did try just adding an 8 to the .cfg file and that didn't work. As @simonster mentioned, mk_arcade_joystick needs the update to allow the hotkeybtn. I'll be trying this when I get home after work, as long as the wife doesn't have me doing anything else -___-
Thanks, guys.

theRog05

@simonster Unfortunately, the first line you mentioned above results in a "repository not found". I tried copying the files manually, but then when I run the 'dkms build' I get "Your kernel headers for kernel 4.9.35-v7+ cannot be found at /lib/modules/4.9.35-v7+/build or /lib/modules/4.9.35-v7+/source". I've tried updating the headers with "sudo apt-get install raspberrypi-kernel-headers", but that didn't work either. Any ideas what else could be wrong?

simonster

It worked for me, but this was some time ago. Try the recalbox copy of the fork

git clone https://github.com/recalbox/mk_arcade_joystick_rpi/tree/hotkeybtn

If you have updated the kernel headers, I don't know why it wont compile.

theRog05

@simonster This also failed to find the repository. :/

simonster

I just ran this command and it cloned successfully:

git clone https://github.com/recalbox/mk_arcade_joystick_rpi.git -b hotkeybtn

I am trying to compile it at the moment (there are a few issues with the code), there is also the matter of the missing headers, so bear with me and when I get something I will update this thread.

simonster

Hi @theRog05

How are you using kernel 4.9.35-v7+? I have just run an update in RetroPie-Setup and am still using kernel 4.4.50-v7+

Can you fill in the detail list in https://retropie.org.uk/forum/topic/3/read-this-first

theRog05

@simonster I've been working on this all day so far and started getting some other funky errors (probably from me messing around in there). So I decided to wipe the card and start fresh. Once I get my card loaded up, I'll give this a try again. Sorry, wish I saw this message before I went and formatted the card.

P.S. - Thanks for your continuous help on this!

simonster

@theRog05

No problem, I can only assume you had run rpi-update at some point and ended up with a unstable beta kernel.

theRog05

@simonster I'm pretty sure I did run rpi-update at some point in the past 7 hours. haha. I do remember using kernel 4.4.50-v7+ and I was also wondering why 4.9.35-v7+ was being used. Oh well, starting fresh now. As soon as I get it loaded on the Pi, I'll follow your steps again to clone the hotkeybtn branch in the mk_arcade_joystick_rpi repo and see what I can come up with. Thanks again!

simonster

I have just tried this method and it worked for me completely:

Install MK_Arcade_Joystick from the drivers in the retropie setup. Then exit Emulation Station by pressing F4

rm -r mk_arcade_joystick_rpi
git clone https://github.com/recalbox/mk_arcade_joystick_rpi.git -b hotkeybtn
sudo mkdir /usr/src/mk_arcade_joystick_rpi-0.1.5.1/
cd mk_arcade_joystick_rpi/
nano dkms.conf

change the line that begins PACKAGE_VERSION to read

PACKAGE_VERSION="0.1.5.1"

Press Ctrl+X and then Y and Enter to exit and save changes

sudo cp -a * /usr/src/mk_arcade_joystick_rpi-0.1.5.1/
sudo dkms build -m mk_arcade_joystick_rpi -v 0.1.5.1
sudo dkms install -m mk_arcade_joystick_rpi -v 0.1.5.1 --force

Once installed, restart the Pi using the following command

sudo shutdown -r -t 0 now

theRog05

@simonster Awesome. I'll give that a try when the card loads back up. And after I replace my sisters shock in her car. -____-

loujez

@simonster your advices on this topic are the most usefull on the net. I'm sorry that therog05 don't follow his own topic. I'm in the same case so i follow every step you are describing with the 4.9.35-v7+ kernel.

On the line :
git clone https://github.com/recalbox/mk_arcade_joystick_rpi.git -b hotkeybtn

i get :
fatal: destination path mk_arcade_joystick_rpi already exist and is not an empty directory

It is impossible to go after.

If you are always following this topic, i'm very intersting by what you can belong to me with your knowledge.

Cheers my friend

simonster

@loujez said in Adding a 9th button to GPIO:

On the line :
git clone https://github.com/recalbox/mk_arcade_joystick_rpi.git -b hotkeybtn

i get :
fatal: destination path mk_arcade_joystick_rpi already exist and is not an empty directory

This means that the folder is already there from a previous installation. Try this before that line:

rm -r mk_arcade_joystick_rpi

I have update the previous post to reflect this.