Questions about Minimig future

[alexh]

As soon as my MiniMig arrives (end of April) I've agreed (in return for getting my board) to try to port the open source Spectrum, C64, Atari ST and Amstrad CPC cores to MiniMig.

The bummer is that you'll all have to reprogram / replace your PIC.

Simon82 wrote:
What could suggest me to buy it compared to a classic A600?

Nothing. With a CF flash as an internal hard drive and a CF flash as a PCMCIA removable disk the A600 beats it (as an Amiga) pants down.

[alexh]

The other Amiga specific bit is the PIC.

I wouldnt hold your breath, I dont have my MiniMig yet.

The current list of open source cores are:

Atari ST
C64
Amstrad CPC
Zx Spectrum
MSX
Vic20
Numerous Arcade Machines

Each will need the MiniMig PCB wrapper porting to it (Sound and VGA output, joystick inputs etc.) and almost certainly some PIC changes (hopefully not too much that you have to swap PIC's between platforms) to get the data in off the MMC card.

[alexh]

downix wrote:
Forgot the Atari jaguar there Alex.

There is an open source FPGA Atari Jaguar? What's the link?

[alexh]

countzero wrote:
I was talking about the Acube production run. Now if any of you are dreaming to interface a Z80 to that I say you're just dreaming.

I think you'll find the Z80 will fit inside the FPGA on the production run ACube and leave enough space for an 8-bit computer or console too.

freqmax wrote:
I meant a HDL-Z80 ofcourse. No reason to buy a physical one in this case.

Deffo.

[alexh]

whiteb wrote:
Which is why you put a copy of Tinybootloader on the pic first so you can flash pic firmware at will.

http://www.etc.ugal.ro/cchiculita/software/picbootloader.htm

Ah, it looks like Tinybootloader *might* be compatible with the MiniMig's 18F252 PIC although the exact part number confuses me.

I was under the impression that PIC's required extra programming voltages!?

Edit:

AFAIK the PIC serial port pins are not wired up to anything on the MiniMig v1.1 PCB board this makes TinyBootloader not much use as it is :-(

It would have to be modified to take it's files from the SD card. And then how do you tell the PIC you want to upgrade?

It is a shame that the serial pins were not wired to the FPGA then with a special FPGA image they could have been routed to the serial port. It still might be possible with a hot-mod to the "spare I/O" pins.

[alexh]

bloodline wrote:
No way would the Jaguar custom chips would fit on a minimig FPGA...

I'd still like the link to the open source Jaguar code though ;-)

[alexh]

That is the netlists (post synthesis) for 1 chip from the unreleased Jaguar 2. Totally useless.

[alexh]

whiteb wrote:

alexh wrote:
AFAIK the PIC serial port pins are not wired up to anything on the MiniMig v1.1 PCB board this makes TinyBootloader not much use as it is

How do you mean, useless ? [snip] Remember, the Pic's Serial port *IS* used (shared) with the minimig Serial via a Jumper.

Ah, you see I didn't know that (as you can see from my post). I guess it is no big deal then.

whiteb wrote:
I put the boot loader on to the pic, (which is the ONLY time you need the Programmer) then I put the pic into the minimig and downloaded the firmware via serial.

Ah, so Minimig's firmware also contains TinyBootloader (or an equivalent) so you can update it?

[alexh]

ChuckT wrote:
I'm assuming it can't handle an external Amiga compatible disk drive.

No.

ChuckT wrote:
Why can't it have a multi-card reader

Expense, practicality. They chose the cheapest easiest format.

ChuckT wrote:
Why only one memory card port

Not enough pins on the FPGA for more than one AND you don't need more than one!

ChuckT wrote:
why be stuck with one or two gigs when you can now buy cards up to 16 gigs?

I've seen MMC cards upto 8GB and they make SD cards upto 32Gbytes but I'm not too sure they work with MiniMig.

ChuckT wrote:
What kind of external keyboard does it accept?

Any keyboard with PS/2 or USB that supports PS/2 legacy mode via adapter.

ChuckT wrote:
I read on Wikipedia there is a problem with Sprites but I haven't heard more about this.

It's true, the current core has several bugs not in Amiga chipse.

ChuckT wrote:
I want it to have an HDMI port or cable for modern televisions

Why HDMI? Modern budget TV's dont have HDMI. They do however have component or VGA.

MiniMig as it shipped has two output modes, 31KHz VGA and 15KHz RGB (SCART). Add to that I am 80% sure I could change MiniMig's core to support component too.

That covers vast majority (all?) modern TV's!

[alexh]

downix wrote:
There's a "netlist to verilog" program source code in there that's pretty complete.

Netlists are verilog. Without the technology files they are useless. Have you even been able to work out what all the cell's originally did?

Plus they are for a console that was never released and no software existed. That's pretty much the definition of useless to me.

downix wrote:
The netlist for the Tom and Jerry is also out there, altho the original site that hosted them went down a while ago.

While "less useless" it still borders on unusable.

downix wrote:
In addition, there is an "oberon.v" file in there that actually is complete

And even if you had the technology cell files, I am sure you've worked out what all the I/O are? And what the timing relationship was between signals?

downix wrote:
Yes, spent some time cleaning that code up.  I almost have the GPU core ready to put into an FPGA.

£50 says you never get it to do anything (worth while).

[alexh]

freqmax wrote:
The Xilinx Spartan-3x series can produce dvi/hdmi out of the box afaik. Provided proper LVDS termination & impedance is used (yes I have investigated the matter in depth).

You sure? I am not as certain. Both DVI and HDMI uses TMDS not LVDS.

[alexh]

nBit7 wrote:
I can not see a reason why you can't drive a TMDS receiver with LVDS transmitter.

I am not an analog expert but looking at the specs I'd say you were wrong.

Shame MiniMig doesn't use a Spartan 3A cos in addition to LVDS it has TMDS I/O :cry:

http://www.xilinx.com/support/documentation/data_sheets/ds529.pdf

Take a look at Page 20

[alexh]

This might be of interest

http://www.onsemi.com/pub_link/Collateral/NB4N316M-D.PDF

[alexh]

nBit7 wrote:
I am taking about the electrical LVDS standard not the protocol called 'LVDS Display Interface (LDI)'.

As am I. {Edit: Oops I see you were replying to Bloodline's post}

[alexh]

freqmax wrote:
When I looked at the TMDS spec (from the DVI spec). I found it 's essentially the same electrically wise. [as LVDS]

Ah, you see I didn't. I think I need to go on a course in Analog electronics.