FPGA Arcade , MIST or Turbo Chameleon 64 ?

[christianlucio]

I am looking for an fpga board to replace my broken A 1200. My Goal ist to put the board into the original Amiga case and use Keyrah or anything similar. I will want this especially to play games via WHDload but also might be interested to do some ractracing. Any suggestions what would be the best choice ? FPGA Arcade ? MIST ? Turbo chameleon with minimig core ? As a bonus it might be nice to also emulate other classics like C64, spectrum or ATARI ST (I know....).

[Lord Aga]

FPGA Arcade seems to be the most advanced.
Still, I would like a FPGA compatible which has a floppy connector. As far as I know there isn't one.

[Leffmann]

The FPGA Arcade specs are up on the new webpage, and it looks to be the best by far:

http://fpgaarcade.com/

[christianlucio]

Yes, it Looks very promising, but am I right: so far there is only the Amiga core and even this not is donwloadable for the public ?

[mfilos]

A nice comparison between MIST and FPGA ARCADE was done some days ago by MikeJ. I'm quoting a post of his from FPGA Arcade forums:

Hi all,

I have no intention of "bashing" the MIST board. Till and I have had a few conversations, he approached me a while ago asking for a development board and I could not deliver - so he made his own. Below is (as far as I can tell) an accurate comparison. Any errors please let me know.

We are all working to deliver open source cores which are as close to the original hardware as possible.
I designed Replay to be what I want - other people have different ideas and are perhaps more cost sensitive.
It has certainly been difficult to get this much functionality shipping at a decent cost. There are now 150 Replay boards in existence, so finally I think we are there ...

General:
MIST - 3 x linear regulator, no protection. Two layer PCB
REPLAY - Thermal fuse (auto reset) + input over voltage protection. 3 x DC-DC for high efficiency (low heat) and higher current supplies. Six layer PCB to maintain good signal integrity.

FPGA :
MIST - Altera Cyclone III EP3C25E in 144pin package. 24,624 LE (flop + lut)
REPLAY - Xilinx XC3S1600E in BGA320 pin package. 33,192 LE (flop + lut)

Video :
MIST - 18* bit resistor converter, unbuffered VGA output.
REPLAY - Chrontel video PHY supporting HDMI/DVI digitial + 24 bit analog DAC. Output buffered by line driver with programmable filter. Option for SVHS/Composite video out using dedicated coder.
* Using 1% resistors results in maximum resolution ~5 bits and standard values cause poor linearity.

Audio :
MIST - Resistor/capacitor filter requiring delta-sigma code in FPGA.
REPLAY - Wolfson HIFI 192KHz 24bit DAC with dedicated analog supply

Memory :
MIST - 32 MByte SDRAM
REPLAY - 64 MByte DDR

Clocking :
MIST - Fixed 27MHz oscillator
REPLAY - 3 channel programmable clock generator – can generate exact base clocks for PAL/NTSC Amiga for example

Keyboard/Mouse :
MIST - USB interface controlled from ARM
REPLAY - PS/2 for mouse and keyboard, USB on daughterboard. An interface has been developed which replaces the PS/2 connector with an internal and external USB port.

Price:
MIST - 199Euro* No approvals ?
REPLAY - 199Euro (+VAT, no SVHS/composite). FCC/CE tested including EMI
* MIST does ship with a case, Replay is half size mini-itx and fits in a standard enclosure. All normally used ports fit in the standard ATX IO window.


The Replay board also has a built in RS232 serial port for debug (can be connected either to FPGA or the ARM).
Replay supports approx 200 IO pins to a number of expansion connectors.

Two daughter boards are currently in design, one contains an optional 68060 processor, Ethernet and USB interfaces.
The other is a JAMMA interface for arcade game enclosures. An IO patch board for developers is available now.

MIST is based on the MINIMIG ARM code, although Till has made a number of improvements.
The Replay software is almost completely rewritten to provide generic platform support. I provide software libraries for the FPGA which handle all IO, OSD etc to make core integration easy.

/MikeJ

[chaos]

Personally, I think both boards are great, and the authors deserve praise for their work.

To sum up all the technical differences mentioned, the Replay board has more memory (and probably memory bandwidth), more pins (which allows for the daughterboard, definitely a nice addition), and potentially higher quality sound & video output. It also has yaqube working on the minimig code

The Mist board is cheaper, has USB keyboard/mouse, and (mostly) complete Atari ST and Amiga cores, plus some ports from Pace, with other cores in the works (C64). It is also available *now*. I am definitely pleased with it (thanks to Till for sending me one!).

I would like to address some of the differences mentioned by MikeJ:

General:
MIST - 3 x linear regulator, no protection. Two layer PCB
REPLAY - Thermal fuse (auto reset) + input over voltage protection. 3 x DC-DC for high efficiency (low heat) and higher current supplies. Six layer PCB to maintain good signal integrity.

The Mist board doesn't use much current, so not much need for DC-DC regulators. They are a nice addition though, although it is possible they produce more noise on the power rails. Also, Mist board doesn't seem to have any problems with signal integrity.

FPGA :
MIST - Altera Cyclone III EP3C25E in 144pin package. 24,624 LE (flop + lut)
REPLAY - Xilinx XC3S1600E in BGA320 pin package. 33,192 LE (flop + lut)

This sounds like marketing material from Xilinx In reality, the Spartan 1600E has more like 29000 LE equivalents, and in my experience the Altera FPGAs usually provide better utilization, so the size of designs for both parts is mostly the same.

Clocking :
MIST - Fixed 27MHz oscillator
REPLAY - 3 channel programmable clock generator – can generate exact base clocks for PAL/NTSC Amiga for example

The Altera CycloneIII has much more capable clock handling inside the FPGA (PLLs instead of DLLs, plus they are chainable and run-time configurable), so no need for external PLL, and all the required clocks can easily be generated inside the FPGA.

The Replay board also has a built in RS232 serial port for debug (can be connected either to FPGA or the ARM).

Likewise for the Mist board.

Both boards are great choices to buy, I guess it depends on what you want to do with them. If the original minimig was a A500 (or A600) recreation, then the Mist is (or, will be) like a slightly expanded, slightly faster A1200. The Replayboard with the 060 daughterboard is more like a very fast A4000.

[christianlucio]

Many thanks for the Information and comparisons so far. Are there ones of you out there with practical experiences with one or more of the fpgas ? Looking forward to hear more.

[robinsonb5]

Originally Posted by christianlucio

Many thanks for the Information and comparisons so far. Are there ones of you out there with practical experiences with one or more of the fpgas ? Looking forward to hear more.

I have both a Chameleon and a MIST. For Amiga use there's not a great deal to choose between them - so it comes down to whether you'd rather have a C64 core, use PS/2 Keyboard and Mouse and the ability to connect to a real C64 (Chameleon), or an Atari ST core and USB keyboard and mouse (MIST).

[christianlucio]

Originally Posted by robinsonb5

I have both a Chameleon and a MIST. For Amiga use there's not a great deal to choose between them - so it comes down to whether you'd rather have a C64 core, use PS/2 Keyboard and Mouse and the ability to connect to a real C64 (Chameleon), or an Atari ST core and USB keyboard and mouse (MIST).

Thanks for your post. Can you give us some info about the compatibility you have experienced ?

[robinsonb5]

Originally Posted by christianlucio

Thanks for your post. Can you give us some info about the compatibility you have experienced ?

Generally pretty good. There are a few games which work on the "real" Minimig but not on the Chameleon / MIST ports - Startdust being one of them, but I know how to fix that, just a question of having time. It's not perfect, of course, but on the whole I haven't found many games that flat out refuse to work. WHDLoad works a treat, too.

i also want a floppy connector

[christianlucio]

Originally Posted by ematech

i also want a floppy connector

Might of course be a Bonus but why so important for you, as almost all software ever written exists on adf/dms files ?

[alexh]

The Suska III-C (the most expensive of all the FPGA boards at €620) includes a floppy disk connector. The open source Suska HDL includes a working re-creation of a WD1772 chip (used in various designs, not just Atari ST).

http://experiment-s.de/en/boards/suska-iii-c/

I commend Wolfgang's attention to detail but I imagine it is unlikely for many retro-computer FPGA developers would go to the effort of implementing a physically functional floppy disk drive controller AND a virtual one too.

(Remember, exact timing can be very important in this component to allow copy protected disks to work etc.)

If you want the data off physical floppy disks, there is always the Kryoflux.