Interfacing Dreamcast VMU save memory directly to controller port.

[Lynxman]

Has anyone come up with a solution to connecting a VMU/memory directly to the controller ports on a Dreamcast? I checked the controller PCB and it needs IC1 to interface between the VMU and cable for something.

I have a Dreamcast with built in Bluetooth in the controller port PCB and can't save while using a bluetooth controller unless I connect a real controller to one of the ports and let it sit by the dreamcast with a VMU in it. I'd like to just eliminate the extra controller and have memory in a dongle either inside or lpugged in the port.

EDIT:

I found this on Aliexpress. I wonder if it has a Rpi Pico inside it or something. https://www.aliexpress.com/item/1005005959674574.html

EDIT:

I guess this is what I'm looking for: https://github.com/cluoma/Pico2Maple-fw

 

[Lynxman]

It works with a USB stick even though USB drives aren't mentioned on Github. This is with the rpi connected to controller port 2 and using a XBOX controller to navigate the Dreamcast wirelessly. I designed a case for it. I haver ordered some smaller Rpi units and wil also try USB4MAPLE. I should be able to make it tiny with those boards. I only have a large original Rpi RP2350 board right now so can only test Pico2Maple.

 

[Lynxman]

Turns out it doesn't use the USB stick but stores VMU saves in the RPI's own storage. Too bad I can't swap banks unless I plug a controller into the PI. Pressing Bootsel does nothing. I wanted to add a button but the source code isn't available. I can try USB4MAPLE instead when I get RP2350 PIs. Pico2Maple works well otherwise and nohing but a Pico and a Dreamcast connector is needed to use it as a single VMU.

EDIT:

I soldered a wire to ground and tried touching the GPIOs and GPIO8 triggered a bank change so that solves that problem.