RetroPie GPIO Adapter Issues

[mylostcause]

I have my GPIO and have assembled it. All of my solder points look(ed) clean but once in attached to the RPi, the RPi fails to boot. If I leave the ribbon cable off the GPIO adapter than only the power light shows on the RPi. With the ribbon cable attached my LED on the controller breakout lights and additional lights are lit on the RPi, but it doesn’t boot up.

I’ve wired the ribbon cable to the original circuit board that came in the SNES case. I’ve tested shorts between different pins with a multimeter and haven’t found anything that seems too telling. Any suggestions would be appreciated before I try to desolder the whole system and build it again.

[petrockblog]

Did you disable “safe mode”? It is needed so that the RPi boots up: Excerpt from the RetroPie GPIO article:
Adding a jumper between pins 5 and 6 of P1 results in /boot/config.txt being ignored (except for avoid_safe_mode) and a default cmdline.txt is applied, followed by loading kernel_emergency.img. As stated in the official forum

if you connect external hardware to that pin, the worst that will happen is it falsely triggers safe mode.
To avoid this safe mode when the adapter is attached a setting has to be made in /boot/config.txt. This could be done, for example, by opening the config.txt with

sudo nano /boot/config.txt

adding

avoid_safe_mode=1

and saving the changes with “Ctrl-X”, which has to be confirmed with “Y”.

Also, the 2×5 pin header needs to point inwards, i.e, the center of the RPi PCB.

Could you post one or two pictures of your assembled adapter here?

[mylostcause]

Yes, avoid_safe_mode is set to 1 in my config.txt file and the 2×5 pin header is pointing in towards the center of the RPi.

Things that I’ve noticed is there is a roughtly 7.5 M Ohm resistance showing between the VCC and the Ground at all times, even with the ribbon cable unplugged. Also going in to the NSES circuit board I have cut a few of the redundant wires short as some of these are shard on the board (vcc, ground, clock) and this can be seen in the image.

[mylostcause]

The last post seemed to strip out my link to the album which is currently at imgur.com/a/kgjEd in larger formats

[petrockblog]

I just had a look on one of my boards with only the tri-state buffer and resistor assembled. I could not measure any resistance between VCC and GND.

If you tell me which test points you are using I could provide the measured resistances of another working and fully assembled GPIO adapter.

[mylostcause]

The value shows up between the VCC and Ground on the 2×5 pins and the pins to the board from the 2×13 (pin 1 and 6 I believe) at the solder points on the board.

[petrockblog]

Hmm, I cannot confirm this resistance, see the attached images.

[mylostcause]

I’ve gone ahead and purchased and assembled a 2nd GPIO adapter, and this one does not have the resistance issues or cause the RPi to hold on boot. I now have a new issue.

Whenever I attempt to enable gamecon_gpio_rpi with SNES-pad config, the system dies with an “Unable to handle kernel paging request” error.

I am not overclocking in any way and have tried to slow the system down in hopes of getting it to work. That did not. Hopefully someone has some suggestions.

[petrockblog]

The gamecon driver was written by the community member “Marqs” (see http://www.raspberrypi.org/phpBB3/viewtopic.php?f=78&t=15787&p=433388&hilit=gamecon#p433388). I do not know how to solve possible problems between Raspbian and the gamecon driver.

Also, I do recommend to use only SNESDev when you are using the RetroPie GPIO Adapter. It is important that the game con driver is not installed in parallel, because both drivers would try to access the same GPIO pins. In case you have not seen this yet: THere is a guide for the RetroPie GPIO Adapter at https://www.petrockblock.com/2013/07/09/getting-started-with-the-retropie-gpio-adapter/.

[mylostcause]

After getting the game con drivers removed I was able to successfully set up and play with the SNES controllers. Thanks for the help!

Are there any pointers on getting the button to work as an ‘esc’ key on single press? I haven’t seen any information about customizing the action in SNESDev.

[petrockblog]

Making SNESDev configurable is still on the to-do list. For now, you would need to change the source code around https://github.com/petrockblog/SNESDev-RPi/blob/master/src/SNESDev.c#L248 and recompile and reinstall SNESDev.

[mylostcause]

Worked perfect, thanks!

[petrockblog]

Glad to hear!

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