Well, here we are mid-2025 and still no R2 board. Must be vaporware like several other next-gen FPGA projects?
Absolutely not! I’ve been documenting the progress on our discord all the way through, but as we near the end of the (very difficult) hardware stage it’s time for an update here. I didn’t want to say too much about it until we had the hardware back as we are very very late with this.
The layout has been extremely challenging to get right without using a silly number of layers. We have a lot of extra debug hardware on this board, which will be removed on the production board, which further complicates things.
The board is going through the final touches now and I’m pretty happy with it. We are going to build a bunch of these, as well as the cost-reduced (and simplified) “Lite” board very soon ™.
A few questions I get asked :
Is it MiSTer2?
No. Replay and MiSTer share some firmware from the very early days of minimig, but we have diverged. Our Linux is based on the Altera reference code, but optimized. Firmware is still being developed, as is the graphical front end and the new framework and scaler.
It’ll be open from the point we start shipping boards to customers, and we encourage everybody to help out – just let us bring the hardware up first. I’m even open to other people producing compatible hardware if they wish.
Will it run XYZ core?
Yes. The board is capable of running everything currently out there. If the core author is happy for us to do so we can build from a remote repository into our framework with minimal changes.
I included the legacy SDRAM to make it very easy to run MiSTer cores without changing the core itself.
Newer cores will make use of the four low latency HyperRAMs on the board.
Top view. The heatsink and optional front/rear/daughter board modules not attached.
The connector at the front is for the Compute/IO module. The audio and front IO signals are passed through the edge connector and can be duplicated on the front board.
Left side internal connectors you have ATX fans, 12-20V input (think Mini-ITX jack) and internal USB2 headers.
The two pin headers top left are for PC-audio and PC-front panel for PC cases.
Right side at the top is an optional JTAG debug module for the FPGA. Then a front panel connector – more on this later. Externals LEDs/buttons and then a four lane PCIe Gen 3 slot.
Across the back from left to right ,you get four USB-A ports, each with its own current limit. USB-C power input, up to 100W. USB-C multi mode SuperSpeed.
Multi mode 4K digital output. RCA analog out from an AsahiKASEI 32 bit codec. Gigabit Ethernet, 30 bit VGA and optical digital out.
The Front and Rear IO modules add things like DB9, SNAC, JAMMA etc.
Bottom side ….
These are a few of the internal layers! The bulk of this will be reused on the smaller boards so it’s worth getting right. I still need to do some trace length matching on the DDR4 and a bit of diff pair tidying.
I’ll post again when the board goes to manufacture, and also show you how Lite looks.
Cheers,
MikeJ