Pi Zero W GBA [BUILD]

TechieAndroid

@moosepr
I set it to speed=90000000 fps=60 after testing it a lot and like these settings. I was wondering what resolution settings I have to choose from that applies to this screen and not the HDMI, like, I guess this screen would be analog (I don't really know I haven't looked at the spec sheet yet). I'm just trying to set everything to 320x240 which is what the screen is. Also I'm curious about changing the overscan since it appears to be off. Will that mess anything up with this screen?

spruce_m00se

@hex Do you have a link for a conversion tutorial? I have simply soldered the 5v input to the old output of the voltage regulator that I removed, in thoery everything after the voltage regulator is still seeinng the same voltage as before.

Hex

@spruce_m00se Kindly create a new thread and tag me. This is getting off topic

spruce_m00se

@hex hold on, hahahaha

moosepr

@techieandroid you only need to change over scan settings if you are getting borders round your screen.

The screen resolution is 240x320, so setting things to that will help. The fbcp will actually scale things, so as long as the aspect ratio is correct, it shouldn't look too bad. You can also change the theme, there are many that are designed to fit the smaller screens

TechieAndroid

@moosepr
Thanks, I turned overscan off in all the configs and set the resolution everywhere I could, it made a big difference in the terminal but emulation station stayed the same even after adding it in the es config.

I've almost finished my project, all I need now is to get the buttons in.
So I'm going to use the GPIO pins for them, I'll use 10 total for the GBA buttons, do I need to use any specific GPIO pins?
And where do I add the code for the buttons when they are wired in?

Thanks

AluLagoa

@techieandroid Any one in green that isn't used by the display is fine, from the following pinout.

alt text

As for driver to use buttons on the GPIO, i used mk_arcade_joystick_rpi. Very easy to get working.

Hope to see some pics soon.

moosepr

@techieandroid i use this for gpio buttons

https://github.com/adafruit/Adafruit-Retrogame

TechieAndroid

@AluLagoa @moosepr
Thanks guys. I've gotten everything desoldered off the GBA board. I'm trying to find the GND on the left and right sides of the board since I'm removing the center part. I'll post pics to show what I think are the correct grounds.

TechieAndroid

alt text

TechieAndroid

I also need to remove the board from screen. There's a few resistors and capacitors, are they going to mess me up it I connect the screen solely from the ribbon cable? Also I need a schematic showing which ribbon cable pins are what, since there are untraceable.

moosepr

@techieandroid the board will have most of its components for the SD card. There will be a resistor for the backlight, and a FET/transistor to allow you to pwm backlight.

I made a simple board that it designed for 14 pin versions of the screen (2.2 inch, no touch)
https://oshpark.com/projects/BP9tGKag

But larger screens have touch, and so I designed this board
https://oshpark.com/projects/zUNmnlLF

The pads on the back are for the touch interface, which most folks don't use. I have not tested the latter board, but I see no reason why it wouldn't work.

Either board needs a smd resistor, 0805 in size, and just 10 ohms

TechieAndroid

@moosepr

Thanks, but I'm not sure my screen will work with either since I'm currently using 9 pins.

alt text

AluLagoa

@techieandroid In my build I don't use the top pin, sdo(miso).

moosepr

@techieandroid my board has the led pin tied to the 3.3v to simplify things. It means you can't adjust the backlight without changing the resistor. Saves you a wire 😀

TechieAndroid

Okay thanks guys I'll check that out. So I can't be sure but maybe the buttons on the right side ground to the same location as the a-gnd (in the pic it's at the end of the alligator clip) which I believe to be the audio ground (speaker probably). And on the left side the buttons could ground to the same spot as the ground for the cartridge. I need to know because this won't work if I cut the center out and can't ground the buttons.

TechieAndroid

Okay I cut my miso cable and the led cable and connected the led to vcc. What was miso doing since it seems to be working fine without it? And giving the backlight 3.3v makes it look better imo. Thanks for the tips. I'm going to test around on the GBA board and see if I can locate ground.

TechieAndroid

YES! I've found the remaining information I needed.

Button programming
https://www.raspberrypi.org/forums/viewtopic.php?f=78&t=83317&p=589292#p589292

GND location
https://assemblergames.com/threads/game-boy-advance-schematic-cadsoft-eagle-files.54814/

I will be completing my project tonight. :]

TechieAndroid

Shoot. I desoldered the screen from the board, mapped out all the traces, soldered to the ribbon cable successfully and it didn't work. Tomorrow I'm going to solder it back to the board, test it, then connect it a bit differently. I'm not giving up. I'll post pics later.

moosepr

@techieandroid the screen will have this pinout

alt text