NTSC MiniMig

[whiteb]

JimS wrote:

whiteb wrote:
How does he tell the minimig what ADF to load ?

I guess I had the notion that it was like a real amiga and would autoboot from df0. Oops. ;-) Might be a nice feature for later...  any adf named df0: or dh0: gets booted.
 

Yeah, would be good.  Dennis You reading this ?

[freqmax]

If someone have some spare money.. why not donate a real 60Hz NTSC CRT + 120VAC 60Hz SINUS inverter to Dennis in Netherlands. I think he got the knowhow to fix initial code to make it run. And then other people can iron out any bugs.
That is if Dennis don't mind.

CRT monitors choke on "modified sinus"..

[alexh]

Dennis wont need any of that junk.

Hardware reference manual, 20 minutes of verilog changes and FPGA recompilation, an NTSC crystal (or 20MHz + DCM change) is all he needs.

Anyone with a minimig, half a brain, and the will to do it, could have a go.

This thread was supposed to be a technical discussion of how to make the verilog changes, but it's now full of crap posts :-)

If you have a MiniMig, try to go back to the front of the thread, read about changing to the NTSC clock frequency.

Then read about changing crystal, DCM and line counters as described by myself and Dennis.

Recompile using the Xilinx toolkit and you should have a working NTSC system.

[Crom00]

Is it possible to fab or mod a minimig with socketed crystal connector and ship the unit with 2 crystals, one for pal and once for NTSC?

The user would then have to laod the correct FPGA data at startup?

Would like to ship a board that can do both ntsc. pal versions.

[alexh]

Crom00 wrote:
Is it possible to fab or mod a minimig with socketed crystal connector and ship the unit with 2 crystals, one for pal and once for NTSC?

I suppose you could, but if you used a 20MHz crystal, as suggested several times in this thread, all you do is change the FPGA image on the MMC.

Would like to ship a board that can do both ntsc. pal versions.

You're going to make and ship boards??

PAL version with ECS support (for 60Hz) would be good enough for most people, but that will require verilog changes and there seems to be no one with a MiniMig board interested in doing any serious work (Except Dennis and Tobias).

[Crom00]

You're going to make and ship boards??

PAL version with ECS support (for 60Hz) would be good enough for most people, but that will require verilog changes and there seems to be no one with a MiniMig board interested in doing any serious work (Except Dennis and Tobias).

Check the thread on this subject, its out there.

Yes I can get stuff manufactured but the verilog thing is over my head unless I teach myself how ot program. Now if you need a pacakge designed,or production done I can help there.

[whiteb]

alexh wrote:
Dennis wont need any of that junk.

Hardware reference manual, 20 minutes of verilog changes and FPGA recompilation, an NTSC crystal (or 20MHz + DCM change) is all he needs.

From memory, Dennis already has the Hardware reference manual, he studied it when making the Core for Minimig.

From what he has told me, he is already working on a PIC update (Something to do with the floppy controller), so do not rule out adding 60hz support yet from Dennis.

[whiteb]

Crom00 wrote:
Is it possible to fab or mod a minimig with socketed crystal connector and ship the unit with 2 crystals, one for pal and once for NTSC?

The user would then have to laod the correct FPGA data at startup?

Would like to ship a board that can do both ntsc. pal versions.

Well, if it uses the internal clock of the FPGA (I think that was one of the options), then it is quite possible to have multiple versions of the core to handle NTSC/PAL/50hz/60hz all in one download place, depending on the user's requirements.

You could also supply boards catered to each person's requirements.

[denli]

alexh wrote:

there seems to be no one with a MiniMig board interested in doing any serious work (Except Dennis and Tobias).

Illuwatar built his own design in mini-ITX format.
http://web.comhem.se/illuwatar/project_pages/minimig/minimig.htm
It supports Composite out.

[alexh]

He didnt change any MiniMig code, did he?

I think he just changed the PCB.

[denli]

He doesn't know Verilog yet.

[alexh]

If he sends me a board, I'll teach him verilog ;-)

[CD32Freak]

Is it possible to fab or mod a minimig with socketed crystal connector..

@Crom00 and others
Here is a building tip on how to make your own crystal socket: http://www.qrpkits.com/buildertip03.html
:-D

[denli]

CD32Freak wrote:

Is it possible to fab or mod a minimig with socketed crystal connector..

@Crom00 and others
Here is a building tip on how to make your own crystal socket: http://www.qrpkits.com/buildertip03.html
:-D

That would be hard for a production run.

[alexh]

In case anyone is still reading this thread (or any threads regarding a 60Hz capable MiniMig).

In addition to changing the crystal, reprogramming the DCM and changing the BEAM constants, you also have to change the AGNUS ID. This is in the VPOSR register.

Code: [Select]


//beamcounter read registers VPOSR and VHPOSR
always @(regaddressin or lof or verbeam or horbeam)
if(regaddressin[8:1]==VPOSR[8:1])
dataout[15:0]={lof,2'b0,1'b1,11'b0,verbeam[8]};
else if(regaddressin[8:1]==VHPOSR[8:1])
dataout[15:0]={verbeam[7:0],horbeam[8:1]};
else
dataout[15:0]=0;
[/font][/size]
I got the values for VPOSR from here:

http://www.winnicki.net/amiga/memmap/VPOSR.html

[Firedawg]

Thanks Alex,  I'm in the process of soldering everything, holding out on the crystals.  I have all the past dialog on the NTSC Minimig subject, which you started, again thanks.  I need to purchase the crystals for the change to NTSC.  When I get to the programming part, that will slow me down some and I will rely on what has been discussed.  Can I use you as a resource when I get to the programming stuff?  I would appreciate it.

Mike
"Firedawg"