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Jan 21, 2017
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Birmingham, UK
I've been hoping to get this one built since the release of the Pi 4 and with the recent advances in vulkan support I am giving it a go. With the rising prices and hardware failures of Naomis I thought it would be good to have a backup/replacement option that is pretty much plug and play into a Naomi or JVS cab. I'm putting together a Pi image for Pi 4 based on Raspbian using Retroarch and lr-flycast with JVSCore and a USB RS485 as controls but you could just as easily use a JVS-PAC. The image includes attract mode as a front end menu and you can also switch to launching a single game if you want via a config file change. Everything runs at 640x480 4:3, video input can be with either HDMI, an HDMI to VGA adaptor or RGB666/VGA Hat, audio via 3.5mm to RCA or you could add an external USB adaptor.

I've built a preliminary image and testing is going really well, hopefully this week I'll be able to get a video up demoing the whole thing. In testing I can get a solid 60fps in some games, others have slight drops during more demanding 3D scenes but hopefully I'll be able to play with the settings and optimise it per game. I tested against the latest Lakka build which is arch based, that uses the newer flycast core that can support Naomi 2 but performance isn't as good.
So wait… your Wi-Pi image has just gone from serving up titles to replacing the whole set-up…? Love it :thumbsup:
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Made some good progress this week, I've pretty much finalised the build and tested that JVSCore all works as expected with the emulator. Thanks to the brilliant @bobbydilley I have a Pi running the OpenJVS hat emulating a hardware JVS IO running into the Pi4 via an RS485 adaptor, kind of a convoluted setup but it means I can test on my desktop instead of in the freezing cold garage. Controls are working as expected with no latency issues, I tried using DietPi to reduce the size of the image but I had some screen tearing issues when rebuilding everything from scratch and I really don't want to go through every installed package so I'll stick with Raspbian Lite for now.

I realised a couple of days ago I'd built the vulkan drivers with the debug flag which was costing a few extra fps, that's now built as release so it optimised as much as it can be with the current build v23.0.1. If you launch from a command line it pops a message about vc4 being not fully compliant but you don't see that when running from attractmode. Boot times are around 30 seconds to the Naomi boot screen using a fast micro SD card with a gd-rom game, slightly less for cart based and less again if booting into attractmode. I'll get some games on there and get a video uploaded, any particular games people want to see running?


Link to my build notes: https://drive.google.com/file/d/1ujA-gHdD0cxQ0WloX4qewmV50iDuiWji/view?usp=share_link
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Nice! can it output 240p (or 480i I guess) RGB for low-res monitor setups?
Managed to get the latest flycast core working this morning, small performance boost and Naomi 2 support enabled but it runs to slow to play without frame skipping :(
I've added a few more features, I've moved all retroarch and attractmode config to /boot so that the rootfs can be made readonly which is much better for switching on and off in a cab without shutting down the Pi. You can also choose either booting to attractmode or a single game and select either 3.5mm jack or hdmi audio output. I've endlessly played with the settings in Retroarch and I think I have the most optimal setup for Flycast. The last piece that needs to be finalised is JVS controls, I've changed the default JVSCore inputs to buttons rather than keys as that messes with X windows in some cases and standardised the device name so that it should map the same way into retroarch with any JVS IO.
Yep, it's still on the map, suffering from project overload at the moment
haha i was watching the Video so i was curious looks interesting, certainly interested