Topic: MIST

Hi Mike,

So, I'm now about ready to buy.  However, before I do, could you please compare the Replay with the MIST and let me know the current availability and pricing of units?

Thanks,
Lee

Re: MIST

Hi Lee,

The main difference between the FPGA Arcade board and the Mist board is that the Replay board emulates the AGA chipset and has a more advanced 68020 processor emulation.
The Mist board emulates the ECS / OCS chipset, the 68000/68010 processor and has an alpha support for the 68020 processor, it can use 4 x virtual floppy drives (for ADF files), it supports also 2 x Hardfiles (HDF format) and can run the Workbench 3.1 (3.5 is supported but is very slow for the moment).
The FPGA Arcade board do the same and adds the AGA support, more memory, and the RTG graphics emulation in the new firmware and core.

Also, the FPGA Arcade board will be able to accept a daughter board which is in development with a real 68060 processor, one ethernet and 2 usb ports.

The FPGA Arcade board can also be installed in any ATX / Micro ATX / Mini ITX case and can use any ATX power supply with the ATX adapter and the backpanel which are sold separatly.

On the contrary, the Mist board is in stock right now at our shop and ready to ship.

The Mist board is like a Minimig with more memory (28MB usable as Chip and Fast), 4 x USB ports instead of PS/2 ports, 2 x DB9 Amiga / Atari joystick ports, one VGA out and one Stereo Jack out.

The FPGA Arcade has one DVI out port, one Stereo Jack out port, 2 x PS/2 ports for mouse and keyboard, 2 x DB9 Amiga / Atari joystick ports and can use 60MB memory.

Thanks, Lionel and Laurent
Amedia Computer France

Amedia Computer France
Site : [url]http://amiga.amedia-computer.com[/url]
Mail : laurent@amedia-computer.com
Skype : faranheit57

Re: MIST

Thank you.  Tbh, I'm thinking about getting both, but I'll probably get the Mist first, as I need one now (I need an FPGA dev board, anyway).

Thanks,
Lee

Re: MIST

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

Re: MIST

Lazarus404 wrote:

Thank you.  Tbh, I'm thinking about getting both, but I'll probably get the Mist first, as I need one now (I need an FPGA dev board, anyway).

Thanks,
Lee

If you need "quickly" just a FPGA dev board first to learn FPGA coding, you should consider to buy exactly such a board. Especially as beginner you may need some FPGA debugging/upload features and easy to connect I/O to add some LEDs, a DSO or a LA. Some also have good tutorials, examples, user manuals, extension boards and software included for a quick start-up on FPGA coding - all in one...

So I don't see any advantage in buying "yet another Minimig clone" (maybe somehow improved) in parallel/favour to the Replay, which follows a much broader approach (in terms of features, expandability, usability and performance). And establishing something new like HDMI/DVI out costs some time, as it is not only copying existing code from somewhere else and use it again on much simpler and similar low-cost hardware...   ;-)

But a "classic" dev board I'd consider as good "add-on invest" to any dedicated (Minimig, Replay, ...) board. I have myself several generic boards (with different FPGA types, external memory and other features useful for development) and still use them beside the Replay for experimenting and (initial) development of code modules. I won't name any board here, it depends strongly on what else you want to do with it. Tthere are quite a lot (expensive and cheap) dev boards out there, google is your friend...

/WoS

6 (edited by IanP 2013-09-01 10:18:19)

Re: MIST

admin wrote:

Hi all,
... Below is (as far as I can tell) an accurate comparison. Any errors please let me know.
...
Video :
MIST    - 12 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.
...
/MikeJ

MIST has an 18 bit resistor converter for video according to the schematic at http://www.harbaum.org/till/mist/schematic.pdf So it is a step up from other Minimig boards in potential graphics capability.

Re: MIST

Hi Ian,
Correct - missed that. Updated.
Till has picked probably the best standard values, but the linearity is still pretty poor. Given 1% resistors the max resolution is somewhere between 5 and 6 bits. I looked (any may still use later) an R-2R design, but for 8 bits you need better than 0.4% resistors.
Best,
MikeJ

Re: MIST

Just for completeness:

Beside INL/DNL given by the resistor matching, such resistor solutions (like the mentioned one and many other low-cost boards) also catch all "dirt" from the FPGA I/O supply into the video signal - so SNR (= effective bits / ENOB) of the video signal will be furthermore reduced. This is also valid for audio out when generated directly from an FPGA pin. Not to mention they may have quite some temperature coefficient as well, if not explicitly "low-TC" versions are used.

Furthermore, a passive r2r network alone provides no good impedance matching and no proper bandlimiting (for accurate signal slopes and levels independent of the external termination). This has again quite some effect on video quality and even depends on cables and connected devices. So I doubt that just adding more resistors will really improve the quality, independent of their basic accuracy ... wink

/WoS

Re: MIST

Thanks Faranheit and Mikej for the comparison details of the two boards.  Given the slightly different flavor of these two boards, and the close price point, I'm still dead set on spending my money on the Replay board.  Lotharek`s does great work, but the price of the MIST is too high to compete with the Replay.

Firedawg