Porting the Mega65 project to MiSTer platform?

My guess is, that it is not trivial to go from Xilinx to Altera FPGA and all different peripheral devices. But that‘s just an uneducated guess and I would love to be proven wrong.

It is questionable if the FPGA of MiSTer is powerful enough to port the MEGA65 there. There was a question once whether a C128 can run on a MiSTer. That was a similar problem.

Zitat von wins4

It is questionable if the FPGA of MiSTer is powerful enough to port the MEGA65 there. There was a question once whether a C128 can run on a MiSTer. That was a similar problem.

This I don't believe at all. Maybe the Cyclone III in the original MiST is not enough, but the Cyclone V SoC in DE10-nano is quite powerful. I'm too lazy to look up the specs right now and compare to the Artix board that is used for MEGA65 development, but just think of the machines, MiSTer can easily recreate: AA-Amiga, ao486 PC, SNES, etc.

And a C128 shouldn't be to complex. It's just an slightliy extended and faster 65xx and a Z80, VIC, SID and VDC. Nothing to complex. I guess even a MiST has enough LEs to stuff a C64 and CPC or Spectrum core together and this would be more complex than a C128. I guess the only reason there is no C128 core for MiST or the Mister is, that there is no real demand. Most people used the C128 with GO64 first.

Most Retro-FPGA users are mostly interested in games and there are no killer games for C128 only. And for the CP/M mode and Z80, there are enough alternatives to C128.

So if I don't miss something important, a C128 core should be doable on inexpensive FPGAs. It's just that no one did it yet.

Zitat von igel65

I‘d like the idea that the Mega65 Project gets ported to the MiSTer Project.

They are also talking here about this idea: misterfpga.org

Zitat von https://misterfpga.org/viewtopic.php?p=1867#p1867

---

While the c65 would be neat, there was zero commercial software made for it and nearly no homebrew software, just a couple simple demos, the c65 mega folks are making their own "re-imagined interpetation" of the machine since the actual machine, filling in the missing gaps, etc.. the real machine was never finalized (and even with real c65 machines there is a lot of incompatibility between the few surviving prototypes) .. so this would really be a "fantasy" interpretation .. like the X16 Commander ..

---

True, the mega65 project is fascinating to follow and they go premium with the hardware, thus it is promising to be a beautiful 8bit machine.

The core may be interesting in a couple of years if and when the homebrew scene takes off on the mega65, but for now there is nothing readily available. The mega65 core may be further developed by then, too.

Alles anzeigen

The 200T is four times more powerful, than the FPGA in the MiSTer.

Zitat von wins4

The 200T is four times more powerful, than the FPGA in the MiSTer.

OK, too much guessing. I always am confused which Artix A7 board is big enough for MEGA65, but from what I found on this forum, already the Artix-7 FPGA XC7A100T should be fine.

So let's compare it with the Cyclone V SE from DE10-Nano/Mister:

Does not look to different, also it is always hard to compare different layouts/modes of logic elements. This comparison to 4-bit lookup tables is always a bit misleading and surely influenced by marketing departments of Xilinx/Intel.

The MEGA64 dev kit seems to have taken the 200T variant, but I don't think that it is really needed for the creation of any 8 bit system. Even complex 32 Bit systems like Minimig-AGA/RTG with fast 68020 32Bit CPU fit into the 25000 LUT4 LEs of the Cyclone III in MiST. The TG68 runs with ~100MHz in the Mister and performance rivals a A4000/EC030. I can't believe that a MEGA65 is more demanding.

At least for the C65 we are talking of a 8Bit low-cost system Commodore planned to rival NES/MasterSystem for people who couldn't afford an Amiga 500 in 1989/90.

Not sure if the MEGA65 mode extensions make it to rival 8/16 Bit SNES or16/32 Bit OCS-Amiga, but surely not a A3000/4000 with ECS/AGA/RTG and 25MHz 68030 32-Bit CPU.

Zitat von igel65

RexRetro

one question.

Does the Artix7 XC7A100T (or 200T) contain also an ARM CPU?

No. Maybe this is a reason to go for a bigger FPGA in the MEGA65 dev kit, so it has enough space to fit an additional "management softcore" (maybe something like RISC-V, that has modern compiler support and can run Linux).

But there are also FPGA/ARM-hardcore SoC from Xilinx, like the Zynq-7000 series. There are inexpensive ZYBO boards similar to DE10-Nano from Digilent.

ZYBO comes with dual Cortex-A9 @ 866MHz, 512MB DDR3, HDMI+VGA, OTG USB2, Gigabit Ethernet, Audio Codec, MicroSD, many Pmod connectors.

But with 28000 LEs, 2.1Mbit BRAM and 80 DSPs the FPGA part is more in the area of the Cyclone3/4 used in MiST/SiDi, and I guess it would be more complicated to use (neighboring) PMods as GPIO for extra SDRAM.

Howdy folks,

It would be great to see the MEGA65 ported to MISTer hardware.

It is indeed an open question as to whether it would fit in the MISTer's FPGA or not. The only way to know for sure is for someone to try it. I'm happy to provide support for someone willing to tackle it.

LG

Paul.

Hallo,

kein Problem, dass Englisch nicht deine Muttersprache ist. Ist sicher auch bemerkbar, dass Deutsch nicht meine ist

Ich wäre ganz froh sein, wenn jemand der MEGA65 an den MISTer portierte, aber leider kann ich nicht der Jemand sein. Ich bin schon total beschäftigt mit der Öffentlichen und Fertigung des MEGA65s. Aber ich würde was ich leisten könnte, an Hand jemand, wenn man Lust und Zeit hätte, daran zu arbeiten.

LG

Paul.

The MEGA65 core is "mostly" finished, but there are still bits and pieces being worked on. For porting to the MISTer board, the main outstanding item is a rework of the memory sub-system, that I am hoping will be done in the next few weeks. This should make it much easier to port to different boards that don't use Xilinx parts, or use external SRAM etc.

LG

Paul.

Zitat von igel65

Hi Paul.

I just had a look who are the members on GitHub for the MiSTer project.

It seems that Alexey Melnikov (sorgelig) is working for the C64 core on MiSTer.

Sorgelig started the Mister project and is the main guy for most Mister cores.

But he ported most from MiST, what should be not too much effort, as he planned Mister as an improved MiST, using a newer Cyclone FPGA and base all on extending a stock Intel starter board instead of a custom designed board like MiST.

Big missing piece was the 32MB SDRAm that was added via GPIO pins. Big selling point is HDMI instead of VGA with different syncs for different cores.

Thanks for the heads up on the MiSTer history.

LG

Paul.