FPGAARCADE Minimig/ST compatible board, comments?

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FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Mon Mar 17, 2008 10:53 pm

Hello all.

I have been developing a board for a while to run the games developed at http://www.fpgaarcade.com. I have also been working towards a gate-level perfect AtariST clone. I decided to include a similar bootloader to Minimig so it can also run the Amiga hardware.

This is how it stands at the moment (its about 90% placed, some components are missing).
Image

The board size is ECX but it has got slightly bigger today and is now "EPIC/ narrow mini-ITX" 17 cm wide by 12 high. It will fit in an ITX case and the two front screws are correct. It is a slightly ~6mm oversize EPIC format.

I wanted to keep the base board as simple as possible, everything platform specific would go on a daughter card. This increases the cost though, so I added some connectors at the top but these would not be fitted. The daughter board can be stuffed with whatever connectors you wish. Two daughter boards are being designed, one has the joystick ports over the bottom connectors and TV out, and the other has a JAMMA edge connector for arcade game cabs.

It has DVI out as well as 30bit analogue RGB on the DVI connector. You can plug in a 15 pin VGA adapter or a cable to your SCART TV. It has a high quality audio output as well.

The PIC has a bootloader so it can be updated by the serial port (if it works!)

The FPGA is quite a bit bigger than the one on Dennis' board (Spartan3E ~ 1.2 M gates), so I am hoping the 68K processor would not need to be fitted and we would use TobiFlex's core. (Hello again!)

The RAM is DDR DRAM and there is 64MB of it, maybe more. I will come up with wrappers for the Minimig code so it runs on this board. What I want to get to is the bootloader loads a default FPGA image at startup which drives the on screen menu. You then choose the platform (Amiga/Atari/Pacman/HD Asteroids etc) and the disk images / roms.

I will do a small production run when it all works as it is tricky to solder BGAs at home :(

Any comments? There is still time to tweak it....
Should the base card have composite / SVHS TV out, or is the DVI into a HDMI tv good enough? Do modern TVs work at 50Hz with HDMI actually, I don't have one???

Thanks,
Mike.
http://www.fpgaarcade.com

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby simbo » Tue Mar 18, 2008 12:30 am

why

atari emulators do a fine job without the £XXXX expense
me for one i dont see the point what an atari hardware that does the job in 4mb ram even 1mb ram does the job
i think for one that steem has steemed out and pressed any clones
its all been done and i think software does the job better than any clone can
as hardware clones = cores and cores need heavy debug and heeps of spent time
i personaly would rather devote to a software clone
at least you can upgrade the core will less hastle than plucking off your flat ball pin array chip
you plan to use its all very well having extended sound and graphics but htf ??? do we address it ???
for crying out load give up now before you fry your nut
upgrade actual hardware that exists fine but even the finest minds here find a flaw in the ideas i put foward
then later magicaly someone add them to there 'idea'
but making a whole new clone i dont see the point
i asked other moderation if a clones hardware section was a good idea {and i for one would love a core clone if it was exact first time } ill see it one day :cheers:
and we all {or most } agreed that it wasnt needed
i for one devote some time to making dll's for a popular electronics simulation tool
and i can say after writing quite a few dlls for this tool that my atari on dll software runs
without a floppy but runs as a realwired up actual atari circuit but using sdcards / mmc as a dll in the same simulation
so far ive written
68000
atari dma
late atari st glue
atari universal shifter
600/400 display dll as a popup window
atari mmu not that its needed
etc,,,
ive worked on most chips atari has as dll's
so whats the point in more landfill
better devote your time to real stuff
and not pie in the sky and a clone of everyone elses clones
non flexable designs what ever case there in will never come close to real hardware
.
like ideas ive had and pubed
it gets ignored and i most often i end up paying and playing with the projects for hardware i make
for self as one or two offs
i see a clone = 20 to 30 customers and a heep of downloads of the pcb
basicaly giving makers of systems a better insight to make custom tables to then import as software... modules
makers game to and access to hardware secrets they dont yet have and some people are loth to share
even modern pc's struggle to match the falcon
if you want to clone a computer clone the falcon on a single core or there is no market :P
mame or mhce{multi home computer emulator} already perform this task
you can buy a table top mame machine that does everything a pc does to software at an advanced level
and doesnt need ANY somewhat lame dedicated advanced unaddressable hardware that sits there 99% of the time unused
and far better than any hardware clone will ever do.....! :( sorry...

simbo

Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby simbo » Tue Mar 18, 2008 2:16 am

your project just smaks of
work with me debug it for me and ill sell it once its done

like mame has done to a firmware pub table top developer that then slam's the door closed

then fix the master bugs youll build in !!!!

do you think we are all stupid >????? ? :mrgreen: or green????

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby belboz » Tue Mar 18, 2008 4:14 am

Looks awesome to me. You can count me in on one!

Love the idea of an ST in a small form factor with the ability to use SD memory, and be able to connect to a computer monitor/lcd.

One question though. Will you be emulating the Atari keyboard controller fully and or support connecting an actual Atari keyboard? I ask because I know the Eifel PS2 interface works nicely, but many games don't work with it since they talk to the keyboard controller directly.

Looks great though.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby unseenmenace » Tue Mar 18, 2008 6:09 am

Sounds pretty cool to me and from the sounds of things (from looking at the FPGA-Arcade website) should be a lot more accurate than current emulators as well. I think the platform specific daughter board idea is an excellent compromise, will you be designing an ST specific one or is that something one of us could have a go at? What are the requirements/limitations for the daughterboard? I also think it would be great to be able to connect a real ST keyboard (i.e. a Mega/TT one). As for the 50Hz question I'm not sure but I believe most TV's are OK for 50Hz whereas a lot of LCD monitors aren't. Personally I use a CRT monitor so that wouldn't be an issue for me. As you can probably tell I am very much interested by such a machine, do you have any rough idea what the cost would be per unit at the moment?
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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby alexh » Tue Mar 18, 2008 8:34 am

simbo wrote:at least you can upgrade the core will less hastle than plucking off your flat ball pin array chip you plan to use

Yeah right, cos that's how you reprogram the core of an FPGA!

simbo wrote:its all very well having extended sound and graphics but htf ??? do we address it ???

The idea would be to replicate extended hardware that already exists. For gfx it would be something like a Nova or a Crazy Dots gfx card. That way the software written for those cards just works! Admitidly getting the hardware specifications of those cards will not be easy.

I thought that the most practical solution would be to send a free board to Mario Beckroft and see if he will release the source code to the Galaxy gfx card under GPL license. The Galaxy gfx card is also an FPGA and already has full software support.

simbo wrote:even the finest minds here find a flaw in the ideas i put foward then later magicaly someone add them to there 'idea' but making a whole new clone i dont see the point

The point is that it is small, much smaller form factor than the original ST or MiniPC. It's got a scandoubler so you can connect to any VGA monitor or Plasma TV. It's got the equivalent of an Eifel built in so you can use modern keyboards and Mice. It does away with hard drives and floppy drives and replaces them with disk images akin to emulators on a flash card. It allows for more than just the ST core, hardware addons can also be replicated.

simbo wrote:i for one would love a core clone if it was exact first time

You ask for the impossible, because you know it is impossible. But due to the nature of the FPGA, as bugs are discovered, you just change the firmware (program) for the FPGA!

simbo wrote:so whats the point in more landfill, better devote your time to real stuff and not pie in the sky clone of everyone elses clones non flexable designs what ever case there in will never come close to real hardware

Wow.

simbo wrote:dispite the FACT there is nothing in the world comes close to it in simulation terms for control over circuits in realtime

Yeah right. Proteus vsm is a forgotton, unloved tool. There are lots more that do the same job better. E.g. CADENCE Virtuoso. But very few people do Multi-Mode sims these days. The digital designers (z80/68k etc.) use a digital simulator, Modelsim, NCSim, VerilogXL, VCS etc. and the analog dudes use Cadence tools. But as you say, no-one engineers in Z80/68k these days, they use 8051 for 8-bit and ARM for 16/32-bit (Maybe MIPS or PPC) but this is RETRO gaming.

simbo wrote:i see a clone = 20 to 30 customers

MiniMig has sold a lot more than 20-30.

belboz wrote:One question though. Will you be emulating the Atari keyboard controller fully and or support connecting an actual Atari keyboard? I ask because I know the Eifel PS2 interface works nicely, but many games don't work with it since they talk to the keyboard controller directly.

Interesting to know, and a question to put to Wolfgang (the author of Suska, the ST FPGA source code).

ppera

Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby ppera » Tue Mar 18, 2008 9:12 am

fpgaarcade wrote:...
The RAM is DDR DRAM and there is 64MB of it, maybe more. I will come up with wrappers for the Minimig code so it runs on this board. What I want to get to is the bootloader loads a default FPGA image at startup which drives the on screen menu. You then choose the platform (Amiga/Atari/Pacman/HD Asteroids etc) and the disk images / roms. ...

Any comments? There is still time to tweak it....
Should the base card have composite / SVHS TV out, or is the DVI into a HDMI tv good enough? Do modern TVs work at 50Hz with HDMI actually, I don't have one???


I think that it is very perspective project. Of course if price will be in range around 100, max 150 Euros.

As I see, it is intended to work with disk images (on boot SD card ?). Since Atari ST is hard disk 'friendly' machine, it would be good that it supports work with SD cards with regular partitions (whether DOS, whether AHDI). It would highly simplify data transfer with PCs, cause we can direct access SD cards, without bothering with images (what is possible with 'some programs' of course :D ). Maybe all it is not big deal - just need to emulate SD card sector access as ACSI access or even simpler as IDE port access. Then regular hard disk drivers would work. Other way would be some kind Xbios level emulation, with special access, maybe via RAM .

I don't see that TV, composite or S-Video out is much necessary now. However there is lot of SW what will not work correct at VGA scanrates - mostly some demos. If it adds not much to price... DMI is too new, and I doubt that more than 1% od people here has such TV.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 9:28 am

Hi Simbo,

Thanks for you detailed response and to Alexh for his responses. Lets clear some stuff up.

I am designing this board not for sales but because it is the platform I want to develop on, other boards are not quite right (in my mind at least). It is a generic modern platform and will run the other stuff I and other people have developed. I am not expecting a lot of help with the hardware and it must run all original code.

A software emulator can get close, but will never be as exact as a hardware copy. The AtariST design I am developing could be used to replace the original custom chips. For example, you want to plug in a harddisk or an original piece of hardware? You wire it up on the expansion board and hook it into the core logic.

So, what is the point? Why do people write software emulators? This is no different, it's no more work and you get a more accurate result because the hardware is identical to the original.

I haven't counted the number of gates in the original ST but it isn't a lot - lets be generous and say 20K. The FPGA on this board (allowing for some marketing crap) is 1.2 Million. Lots of room for expansion. It will never be 100% correct first time, but you simply recompile the source and copy the binary onto the flash disk. The FPGA is reconfigured every time it is powered up and you have new hardware. This is no reason why the Falcon or some other enhanced ST could not be implemented.

Bebloz, the keyboard controller will have to be implemented. I have the firmware for the keyboard processor and a cpu core to run it (hopefully) - haven't tried it yet.

There will be an Amiga/ST breakout board with some user IO, joystick connectors and tv out (if it isn't on the main board) and maybe a floppy connector as I want to play with the floppy controller. No real limitations for the daughter board, you can do what you want. Signals to the FPGA are 3.3V so you will need to be a bit careful with 5V stuff, but adding an ST keyboard would be no problem at all.

No idea on cost yet, sorry.
/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 9:34 am

"I don't see that TV, composite or S-Video out is much necessary now. However there is lot of SW what will not work correct at VGA scanrates - mostly some demos. If it adds not much to price... DMI is too new, and I doubt that more than 1% od people here has such TV."

A HDMI TV will take a DVI input with the right cable. Most monitors won't take 50Hz. One solutions is to use the external memory to frame double to 100Hz but then we will get a slight lag to the screen or flicker. Not ideal.

The options currently are:

Standard DVI/Analogue to your computer monitor if it will do 50Hz 31K line doubled.

PAL/NTSC VGA output over DVI to HDMI TV.

PAL/NTSC VGA output to TV SCART / original 15KHz monitor (best solution)

Composite / SVHS out to monitor/TV

/Mike
Last edited by fpgaarcade on Tue Mar 18, 2008 10:21 am, edited 1 time in total.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby Joel » Tue Mar 18, 2008 10:17 am

I don't see that TV, composite or S-Video out is much necessary now.


I don't agree with that at all. A lot of demos and games don't look right on computer monitors because they were made to take advantage of TV hardware.

Simbo > Were you drunk when you typed all that?

I'm really surprised by some of what's been said here.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby ppera » Tue Mar 18, 2008 10:21 am

fpgaarcade wrote:....
PAL/NTSC VGA output to TV SCART / original 15KHz monitor (best solution)
...
/Mike


VGA has 31KHz horizontal. You probably think RGB at PAL/NTSC scanrates .
Still not clear about SD card... What filesystem, partitioning it uses for holding bootloader, disk images?
What disk images are supported?

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby Joel » Tue Mar 18, 2008 10:26 am

I think he might mean there is a jumper or switch to change from 15-31khz as on the Minimig.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby ppera » Tue Mar 18, 2008 10:27 am

Joel wrote:
I don't see that TV, composite or S-Video out is much necessary now.


I don't agree with that at all. A lot of demos and games don't look right on computer monitors because they were made to take advantage of TV hardware.



Well, I'm one of those who not spent much time watching demos. I know that many is made special for TV, interlaced display, and must work at exact scanrates, timing.
And I bet that it will be very hard to achieve exact emulation for many demos, to work correct.
So, maybe to leave it for later times. For beginning we should be satisfied if majority of games will work.
Based on Falcon experience, most of them will work fine on VGA output.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 10:40 am

"VGA has 31KHz horizontal. You probably think RGB at PAL/NTSC scanrates ."

We can output whatever we want on the VGA connector, so in 15K mode we output RGB and composite SYNC which can be directly wired to a 15K monitor / TV.

In line double (31KHz) mode each line is buffered and sent twice so you can use a standard VGA monitor. Problem is at PAL rates you still get 50Hz vertical freq and some flatscreens don't like this (analogue VGA monitors usually arey ok). Another trick is to frame double as well as line double (100Hz, 31KHz) but this is a bit more complex and adds lag.

Hi-Res/60HZ mode on the Atari will work fine of course now with the DVI out :)


SD card is formated fat16. I am chatting to Dennis about this as the loader is based on the Minimig code.
A init.bit binary is booted into the FPGA. This boots up and get the OSD running. You then choose the platform FPGA image and a disk image.
Initially at least a single disk image (.st or .msa) can be chosen and will be accessed at low level by a floppy controller in the FPGA.
It would be interesting to extend this to allow a real file system, and it is possible as all the accesses post FPGA load are controlled from the FPGA. We are stuck with fat16 though.

/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 10:42 am

"And I bet that it will be very hard to achieve exact emulation for many demos, to work correct."

I intend to get it absolutely spot on.... If it is not accurate you might as well use a software emulator.
I have run the FPGA code in lock step with the real atari chips: http://home.freeuk.com/fpgaarcade/atari_amiga.htm
/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby ppera » Tue Mar 18, 2008 10:46 am

fpgaarcade wrote:SD card is formated fat16. I am chatting to Dennis about this as the loader is based on the Minimig code.
A init.bit binary is booted into the FPGA. This boots up and get the OSD running. You then choose the platform FPGA image and a disk image.
Initially at least a single disk image (.st or .msa) can be chosen and will be accessed at low level by a floppy controller in the FPGA.
It would be interesting to extend this to allow a real file system, and it is possible as all the accesses post FPGA load are controlled from the FPGA. We are stuck with fat16 though.
/Mike


OK, now clear with video outputs. 60 Hz should be good for most cases.

FAT16 is OK. Especially because SD cards are limited on 2GB too :D (at this moment).
My point is that we should allow sector-level access to SD card from emulated Atari . then it can access FAT16 partition(s) directly - since it has FAT16 support in TOS.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 11:21 am

"allow sector-level access to SD card from emulated Atari . then it can access FAT16 partition(s) directly - since it has FAT16 support in TOS."

super, I forgot that.

It may just work out of the tin actually.
In Image File mode the PIC is handling the block transfers to the card within the selected disk image.
Driving direct from the FPGA we map the whole disk and the ST should understand the file system.

mmm lets takes this off line - any help is appreciated!

/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby alexh » Tue Mar 18, 2008 11:48 am

I am not sure what the difference is but MiniMig supported MMC cards. I am not sure if this includes SD cards

ppera wrote:FAT16 is OK. Especially because SD cards are limited on 2GB too :D (at this moment).

Yes, It would be good if we could modify the PIC to support SDHC cards.

I'm going to see if we can get SDHC and fat32 support into MiniMig's PIC sometime next month (assuming they send me a PCB). There is an open source FAT32 library designed for PIC processors http://www.robs-projects.com/filelib.html (Dunno if it will fit in the MiniMig's PIC yet, or how much work it will be to get it integrated).

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 12:45 pm

good point, I was being a bit slack with the language. Technically at the moment it is MMC cards which are supported.

Before I complete layout I'm going to investigate and compile the PIC.
Alex, which compiler are you using?

We can still change to a smaller/bigger device and I am not against moving to an AVR either. I can support Minimig with either I think.
/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby ppera » Tue Mar 18, 2008 3:22 pm

alexh wrote:...
I'm going to see if we can get SDHC and fat32 support into MiniMig's PIC sometime next month (assuming they send me a PCB). There is an open source FAT32 library designed for PIC processors http://www.robs-projects.com/filelib.html (Dunno if it will fit in the MiniMig's PIC yet, or how much work it will be to get it integrated).


I'm not sure that FAT32 is necessary. We can have several FAT16 partitions on one card, and even on 8GB can use for instance 16x500MB. Of course, if it is not big deal FAT32 is welcome. Although I doubt that people will run Mint on board :D

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Tue Mar 18, 2008 11:08 pm

looking at Dennis' PIC code, it seems to support MMC and SD. still investigating .

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby alexh » Wed Mar 19, 2008 12:12 am

fpgaarcade wrote:looking at Dennis' PIC code, it seems to support MMC and SD. still investigating .

Technically or from the comments?

Here are a few technical links I found while researching MiniMig stuff for Acube:

http://www.freelabs.com/~whitis/sd_card/

http://www.ccsinfo.com/forum/viewtopic. ... sc&start=0

http://www.embedded-code.com/product_in ... ucts_id=42

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Wed Mar 19, 2008 11:26 am

Right, the current code supports both MMC and SD cards as long as they support SPI mode (they are all supposed to).

This is quite useful
http://www.cs.ucr.edu/~amitra/sdcard/Ad ... _foust.pdf

The code hits the card to start it up, and if it complains it is an SD card and it sets it into SPI mode.

I was hoping to use the 4 pin SD native mode but apparently you have to pay a license fee so we are stuck with SPI.

Does anybody know of a CPU which has 2 SPI connections?
/Mike

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby alexh » Wed Mar 19, 2008 12:10 pm

fpgaarcade wrote:Does anybody know of a CPU which has 2 SPI connections?

By CPU do you mean a PIC or equivalent? Lots have two chip select & clock lines.

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Re: FPGAARCADE Minimig/ST compatible board, comments?

Postby fpgaarcade » Wed Mar 19, 2008 1:13 pm

yeah, PIC or AVR etc.
I would like two hardware SPI blocks. Then I don't need any clock gating between the PIC and the card, and the FPGA can have a direct connection to the PIC. This would let us transfer the current disk block from PIC to FPGA which transfering the next one from the card to PIC.

Even if memory doesn't allow this it simplifies the connections. I think the reason Dennis gates off the clock to the SD card is that it gets confused while the PIC -> FPGA transfer is going on.

I think we should have two modes for FPGA access, one the FPGA requests a sector relative to the current loaded disk image file ("floppy mode") - this is how it works at the moment. In the other mode the FPGA can access a sector relative to the start of the SD disk. Then, the ST would see in principle the whole fat16 file system on the card.

/Mike


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