From here on out I am going to keep all updates and new tidbits on the WiiU Gamepad with a RPi CM4 with RetroPie project. I will try and keep big updates pointed out, but it is going to be a little bit of a work in progress as I am going to use it to help keep myself on track and noted. 

It is time to fire up the CM4 on the Geekworm CM4 Stick, a mini carrier board, make sure it works, and start the WiiU4Pi build. 

This Raspberry Pi CM4 is the one I ordered from AliExpress in China. It took a while for it to show up and just about as long for me to boot it up. It cost a pretty penny, but as stocks are iffy at best, and I took a chance. So far so good, expensive, but good.  

The Geekworm CM4 Stick mini carrier Board is a nice product that can fit the bill for many a project. I had looked at getting a full-sized Raspberry Pi 4 and stripping it down, but I didn’t really want to risk messing up a board pulling things off. Space inside the WiiU gamepad is tight as a goal is not to remove any material if possible. 

The card is a little bigger than the Compute Module 4 itself, and offers an array of connections. There is a full-size HDMI, USB A, USB C for power, spot for a camera, microSD card slot, 4-pin connector for a fan, a reset button, and 14 GPIO with 6 extra pins for GND and power. A nice function of the card, with the aid of a switch, is the ability to plug it into a computer, and download to it or have it function as the Compute Module. I have not tried this yet, as the module I have requires a microSD card. I have been impressed with the board so far. There is a heat sink and fan on the way so the fan connector will be tested. I am tempted to remove the USB port which sticks out and used to plug into a PC. Ideas to ponder. 

It was a little dicey. The first boot, then second boot, third boot, and still no sign of life. Well, time to check the image first. I pull the SD from the CM4 and pop it in the RPi 4 and make sure it was good.  While I was there I took a couple of minutes to make sure to configure a couple of items; wireless, the USB ports, and log2 ram.

The USB ports are disabled by default. The USB fix is a quick edit of the /boot/config.txt file. Adding the line dtoverlay=dwc2,dr_mode=host and reboot. The USB ports are ready to go. Once the ports are up and ready, I could use a keyboard to complete the setup with raspy-config. 

I need to track down an antenna for it from someplace. The scary part is I know I have more than one laying around. 


She boots

Now it is time to put together the Teensy and the controllers while the screen is on order. I am going to use the 7″ for right now.

FreeCAD will be used for creating the model for the new faceplate. I couldn’t find a 6 inch screen, that was HDMI ready. I was able to find a 5″ Kuman LCD Touchscreen HDMI. With a little configuration added to the /boot/config.txt file it came right up. The following lines were used.

I configured and setup everything on the full-sized PI 4 first. It is just easier as it has multiple USB ports. Once it’s done I move it over to portable retro game system. RetroPie is working well on the RPi 4, I am sure it will be the same on the module. Both of them are configured with 4GB of RAM so there shouldn’t be any surprises.

hdmi_cvt=800 400 60 6 0 0 0 

It look pretty good
Getting ready for a little command line moving of ROMS

The 2 short-term goals are 1) finish design of the faceplate and 2) map out the GPIOs to the modules I have to hook up. I am still short a small PCB USB hub, but I am on the hunt. Worse comes to worse have some PCBs made up and go for the long wait of a Fe1.1s USB chip.

Terrible fit time for a new idea

The original idea was to use the U 180 degree HDMI connector that came with the screen. Unfortunately the screen was made for the full-sized model 4’s header so the SPI pins can be used. Well, shoot, it was worth a try. Maybe a ribbon cable? Short but how short HDMI cable?

Starting to size things up for mounting

While that is mulled about I have started thinking about the placement of the Carrier Board and screen. For now I am using the tray that held in the original WiiU gamepad screen. A custom PCB to put on the right-hand side is an idea high on the list. Keeping wires too a minimum would be nice and I think the modules are small enough to fit there. Time for some more measurements.

A rough check for size and fit

A square fit is a must

I have been working on matte cutting for picture frames. I have yet to work out the mounting holes. The factory mounts are on the back of the screen. Maybe there will be a bracket of some sort involved. I like to keep track of my numbers. And then double-check everything just to make sure. I don’t have a 3-D printer yet so this will have to be farmed out to a friend or business. I don’t want to have to do it more than once, but that is rarely the case no matter how well planned. 




This is just some filler text so I can check out some formatting issues I seem to be having. I don’t think it is the browser. 


Checking the space needed for PCB

© 2022, wrightmac. All rights reserved.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.