Minimig Discussion Forum

Hi,

a few hours ago Dirk (aka dirkv in amiga.org) send me his FPGA64 core source code to check it on Minimig.
After some fixup in reset handling the core was booting and a native C64 is working inside the Spartan3 fpga.

Visual image:


The core is not yet able to load any program nor to access some kind of floppy drive. In the future the free spare-i/o connector could be used as IEC bus. Maybe another PIC firmware could handle .d64 files via SD card

Due to existing ROM copyrights inside the core I will not provide this file to the public.
I do own a real C64 and its ROM chips.

Looks good! Dirk is just ripping it up... Good job Boing!

I like the debug line at the top of the screen.... was that an addition to the core, or is it already present in FPGA64?

Peter has removed the debug line only in the c-one version of FPGA64, because there is not enough space in the 10K100.
The line is really useful and its possible to remove it in other cores,too. Onother option would be to make it switchable.

Awesome! Is this based on the COne core ?

Just wondering, is there a roadmap for this core, like...what do you want to add to the core for support, and when you plan on releasing etc ?

Also: You write that one must change FW to manage to get c64 core to load d64 files from SD card. This sounds like we have to rewrite the FW every time we switch from amiga-core to c64-core. Or do you mean to combine somthing into today existing minimig firmware so that c64-core _also_ can load from sd card ?


Anyway, great work guys. It looks very nice.


BTW: Would a cartridge support work ? E.g. Action Replay ..like it does on minimig ? It would be nice to freeze games and also have it for programming purposes.


Regs
Espen

This FPGA 64 Core is from the C-one. It should be Version 025.
Peter Wendrich made the sources available for downloading.
http://www.syntiac.com/fpga64.html
The sources contain a top level for xes1000 Spartan 3 Board which i modified first for
my spartan 3 board and then for minimg.I also mapped a SID core without filters to the
fpga 64 so it has sound,too.

The C-one has a cartridge port and the FPGA core support it.Dunno if action replay or others freezers
are working but the minimig has not enough free IO ports for mapping a cartridge. It should be possible
to build freezer functions into the core.

Dirk

Oh, nice. Do you know if there exist a sid engine which support filters aswell ? Filters on SID is essential, but of course, not crucial ...yet nice to have if possible

About cartridges. When you say that the fpga does not have enought free IO ports for mapping a cartridge, do you then refer to having an external cartidge physically connected to the board, or do you mean internal IO ports to map a virtual cartridge built into the core ? BTW: Can a cartridgefile be loaded into ram upon boot of the c64 core so it can use it from there somehow ? Would that help ?

How do they C-One workaround this to enable cartridge support ?

The minimig should have had such a expansion slot like the classic amiga has, so that one could connect HW there. I wonder if that would make much sense in a FPGA minimig environment compared to classic A500´s expansion slot.


Damn, I forgot to take home the USB2PS2 adapter today, so I cannot connect my kbd yet. I am awaiting Yaqube´s new FW with s-video built into it (so that my MiniITX minimig doesn´t lose its svideo capabilities....the current released FW from yaqube does not have the svideo in the FW.)


Espen

SID is implemented but without filters. As far as Dirk told me filters are very complex circuits and take much fpga space. It could possibly not fit into the s3 400 fpga.

Cartridges also take a lot of blockram (space in fpga) and there are only a few left and not enough to hold any C64 module (action replay or game). To load a cartridges rom into s-ram is possible but in this case the PIC must be reprogrammed! Until now PIC loads up "minimig1.bin" containing fpga64 core and then "stops" because the fpga is not aware of the PIC and dont ask for more data. Even if this would work, the cartridges rom has to be named "KICK.ROM" to be compatible with current PIC firmware.

You see its not that easy to port another core to the minimig board without also adapting many other things. PIC coding is a bit too hard for me and even if it works the firmware has to be reflashed all the time when switching from Amiga to C64 and the other way arround.

First lets be happy with a working C64 core and soon IEC bus via spare-i/o

repost from a.org
http://www.a1k.org/forum/showpost.php?p ... tcount=197

This is good news, B4k. Looks nice. I can connect my 1581 or even the 1541-3 to this then. How nice

About loading cartirdge roms into sram, I guess this must be the way to go. Just like you describe that minimig loads
its kick.rom file into the sram. It is for sure a possibility. If one lets the FPGA core know of the kick.rom (aka. actionreplay.bin or something), the fpga must know about the pic and its loader then. Maybe it is possible to extract the source from the minimig core to get this compatibility ? It would for sure be awesome.

However, since the minimigs a500 core has actionreplay support with freeze (BREAK key) function, I guess that it should also work on the c64 core...in theory. And probably also in real life if the core was adapted.

I wonder, is it possible (does the minimig has any pins) to connect a real SID chip and let the c64 core know of this and how to address it, so that we can get "real" SID music through the SID chip ? Is this a crazy though, or actually doable ?


Regs
Espen

Its possible, but not on minimig Board.
The DE1 Board i.e would have enough io spare pins. You need a levelshifter also, the fpga IOs are 3,3 V , SID has 5V for logic.