Minimig v1.1 ARM Hardfile Demonstration

[Darrin]

yaqube wrote:
The Minimig in the video is equipped with 20 MHz 68SEC000 (the price difference between 16 and 20 MHz version was marginal). The speed gain of the CPU run @ 28 MHz over standard A600 is only 2.91 due to memory running at 7 MHz and being shared with custom chips. I have also made some tests with memory run @ 14 MHz (requires faster memory chips) and achieved speed gain of 5.05.

I have made some tests to find out what the maximum operational frequency of the 68SEC000 rated at 20MHz is and mine is able to run at 39 MHz. But without equally fast memory access the speed gain is very small (SysInfo reports 3.03 times the A600 speed).

I do not expect the 16 MHz rated parts to be much slower.

So you don't foresee any problems with the 16MHz chip being run at 28 Mhz?

Are you planning a new core release for the unmodified v1.1 anytime soon (bug fixes, df1:, etc)?

[Darrin]

yaqube wrote:

That's my expectation. Actual tests will reveal if it runs or not.

I'll let you know if my Minimig melts.  :-D

Yep, I have already rewritten some parts to make the Minimig more cycle exact (it's not 100% exact and will never be) and now some games and demos work in the same way as run on a real Amiga.
But there are still some others that do not run correctly and I would like to find out why and fix the problems if feasible.

After implementing upgrades from SD-Card for the ARM controller board I will port the firmware to the PIC (most of it has been already done). The FPGA core will be the same for the ARM and the PIC (only the former will allow to have 4 floppy drives and hard disk support).

Excellent news.  Cheers.  :-)

[Darrin]

Everblue wrote:
Does it mean that on an unmodified 1.1, we will still get HDD support and multiple floppy drive emulation?

No and yes, just the updated bug-fixed core with df0: and df1: support, but it will be "expansion board ready" should they become available.

[Darrin]

Yep, that's the plan.  If I understand correctly, the new core will require a PIC update and provide the bug fixes, df1: support and probably the 28MHz CPU.

If you want the extra HD support and df2: and df3: then just replace the PIC with the ARM board.

If you want the extra RAM then you'll need to do (or have someone else do it) some soldering.

[Darrin]

yaqube wrote:
But unfortunately the original Minimig board design imposes a limitation on the maximum communication speed with an SD/MMC card. To overcome this problem you need to short two pads of two resistors (very simple soldering task). Otherwise the emulated hard disk transfer speed is limited to ca 200 KB/s.

Does that mean that with the ARM and the pad shorted you could implement a "turbo floppy mode" where the read/write speed to the ADF images is accelerated?

[Darrin]

Everblue wrote:
Probably that would be a problem to some games? Just a very wild guess.

Probably.  It would have to be optional as in WinUAE.

[Darrin]

Schoenfeld wrote:
What exactly is the limiting speed factor of the hardfile implementation? We just finished an internal version of the Minimig core for the C-One with harddrive support, working on a real harddrive (in my case, on a DeLock IDE flash module). Without optimization, our performance is 545k per second (see pictures on www.c64upgra.de/c-one ) - a good 20% faster than what's shown in the Youtube video.

There might be room for improvement as we speed up the CPU, but I don't expect much more, as the CPU is just a plain, 68000, sharing the bus with the chipset and another 68000 CPU.

Minimig on the C-One now has 11 megs of ram and a harddrive. An RTC might be an idea now :-)

Jens

Bloody hell!  That's good news!  I certainly don't mind using one of my spare 2.5" IDE hard drives on my C-One if it works!  Only a couple more days until I get home and then I can finally mount that C-One in a case and start testing it.  :-)

RTC would be nice, but I'll tell you want would really get me going... being able to access those clockports.  If you could manage that then the C-One Minimig could have a Subway USB device attached.

RTG via a PCI graphics card would be the ultimate wet dream.   :-)

Are you still beta-testing that core with hard drive support or has it been released?

Cheers,

Darrin

Edit:  I just found your post on Yahoo quoted on Minimig.net and I'll be happy to wait for your CF support like you suggest, rather than risk my C-One board to any reflashing or soldering.