NTSC MiniMig

[alexh]

Piru wrote:
So does this mean I can remove the obviously wrong quote from alexh? (about system running at different speed when you toggle between PAL/NTSC display modes.. Amiga bus clock does NOT change, nor the CPU clock)

From what I can tell, and what Dennis has said yes. A PAL Amiga running in NTSC mode doesnt change the bus clock speed.

Some music players run at different speed because they're timed to the vertical blanking frequency, and not CIA timers (vertical blank rate is 50Hz for PAL and 60Hz for NTSC, CIA timer speed remains the same regardless of the display mode.

That's what I concluded. There are fewer lines and a faster frequency and hence a shorter VBL period.

PAL and NTSC systems do have different system base clocks and thus different CIA clocks. The system base clock - and thus the CIA base clock - do not change depending on the screenmode). The only speed gain in 3D games from NTSC is the smaller area to render.

Yes. I think a true NTSC Amiga will have a faster bus/CPU clock than it's PAL rival, but it is so small, would it have  made a difference? The Atari ST people always used to shout about their 8MHz vs our 7.09MHz (PAL)

Now that I think about it, what MiniMig probably wants is the full deal: Changing the base clock aswell (that is really change between PAL and NTSC, not just the display mode). However, this cannot be done runtime (restart is needed).

Maybe, but I would imagine an ECS PAL Amiga at 60Hz to be more compatible than an NTSC Amiga at 60Hz? But there may be nothing in it.

[Piru]

@alexh

I think an NTSC Amiga will have a faster bus/CPU clock than it's PAL rival, but it is so small.

Yes. However, PAL system displaying NTSC screen doesn't have this benefit.

[freqmax]

@Piru:
Actually you can use two DCM's to have both PAL & NTSC timing (SECAM?:-).).
There are four DCMs asfair in XC3S400 true also for XC3S500E btw. So with both signals available at runtime you could implement an OSD switch if you like.
I have also figured out how to change fpga core on the fly with the existing hardware design.

[Piru]

@freqmax

The problem is that the CIA base frequency is determined at a very early stage during the system boot. This means that if you change the timing runtime the CIAs will run either too fast or slow.

[Doobrey]

IIRC, it's only timer.device that needs to know what frequency the CIAs are run at
So you could have a little app writes to a register in the FPGA to select the master clock, and then poke in the PAL or NTSC values for TD_ECLOCKHERTZ,TD_ECLOCKCONST1,TD_ECLOCKCONST2 to switch modes without rebooting.

[Piru]

@Doobrey

That still would not work. Any app can get the eclockfrequency and store it locally. There is no way to patch these. And how about some currently running CIA timer? Would you just make this timer run too fast/slow?

[nBit7]

I am 1000% sure that games DEFINITELY run faster in NTSC mode............Positive! not just 3D games............platformers too.

Thats because they derive there timing from the VBL.  timing graphics movement to the screen refresh means you get nice fluid movement.  And why you typically don't from a PC.

[Piru]

@leirbag28

Nowhere was I disputing the fact that games that have both NTSC and PAL versions run faster in NTSC. There is after all less to render, aswell as less bitplane data to fetch with DMA. Faster screen refresh (60Hz vs 50Hz) is also often perceived as "running faster", if the game speed is locked to the VBL.

What I said was: toggling betweek PAL and NTSC screenmodes does not change the system base clock or the CIA clock. CPU runs exactly the same speed, too.

[leirbag28]

Hmm.............interesting...........but all technical.  If I were to have an argument or dicussion with someone about the possibility of speeding up a game thats tweaked to the max on a 68000 machine in PAL and NTSC, most of you might say its not possible to speed up the CPU..........so the game wont run faster.

and I say ITs possible to make the game run faster..........whatever the technical reason (VBL in this case I guess)   the bottom line is that I as a customer dont care for the reasoning behind the technicalities.......I care if its possible or not............and it is! despite that thge CPU isnt running faster.

I hope yall can see from a conversation like this that somtimes one has to remove themselves from the technical side of things to be able to have a more open mind on things like this, such as doing the "impossible" and making it possible...............sometimes one has to go around and outside of the "Box of techincality"  I believe anything is possible.

I once argued that its possible to have FIreWire on an A1200 with a 68030 (wich I still do believe is possible)  but I might be told that:

The CPU cant handle or catch up the the speed transfer of firewire and the Bus cant handle it no matter what.

I of course would beg to differ.............there are ways.

One way is to create an external capture card with the FIrewire interface input that cathches the data, and slows it down for intake through the parallel or serial port of the Amiga.  (just an idea or example of how it can be done)



All things are possible.  BY the way, has anyone yet tried the Game I recommended wich looks the same in both PAL and NTSC on both PAL and NTSC machines?   One Must NOT use a 1084 or anykind of Amiga monitor or monitor that adjusts itself into PAL or NTSC.  Most TV's should work if they will at least display the image without the V-HOLD going crazy.

THis guy has done a game RIGHT!  he shows how one can make a game that runs perfect for both PAL and NTSC without having chopped borders or slowdown or speed up.  Amazing game:  OUTFALL

Get it!  more people should program like this...........I wish WHDload could do this to games.  THis way of doing things would save developers alot of time and money.

[AmigaHeretic]

I don't know if this adds to the discussion much, but I know if you run Sysinfo in NTSC and then PAL you get 2 different CPU speeds.

I can't remember which was faster at the moment, but I think it was PAL and I use to put my Amiga in PAL to make it look like the CPU was running faster to show my friends when I did speed tests.  Worked without restarting.  Put it back in NTSC and it run a few MHZ slower. (030 50mhz) With a plain 68000 it was just a few tenths of a mhz difference.

[AmigaHeretic]

I once argued that its possible to have FIreWire on an A1200 with a 68030 (wich I still do believe is possible) but I might be told that:    The CPU cant handle or catch up the the speed transfer of firewire and the Bus cant handle it no matter what.    I of course would beg to differ.............there are ways.

Oh there have ALWAYS been neigh sayers.

I remeber, even before Commodore went bankrupt, so this was a while ago...

Parallel Port ZIP drives??  Remember those?  FOREVER people said that there is NO WAY to use those on an Amiga.  The Parallel port is TOO different from the PC one.  It doesn't have enough interupts, blah blah blah.

Anytime people would ask if they could use one on their Amiga some one would post and say it was NO NO NO you're all stupid, it can't be done, you just don't understand how the parallel port works and how the ZIP drive works.

Well, guess what?   I used one for YEARS.  You can still download the simple little driver off of of Aminet.  Yep some guy figured it out instead of just {bleep}ing.

I even used one basically as a harddrive on my CD32 system for a long time.  Just had a floppy that had some very very basic commands (like maybe just c:assign) with that driver and just assigned everything to the ZIP drive.  assign C: Zip:C   assign S: ZIP:s etc...
Worked great for a long time.

[alexh]

Another MiniMig thread clogged up with non-technical crap. :-(

Does anyone who needs NTSC / 60Hz have a working MiniMig?

Is anyone actually interested in working towards 60Hz capability? Actually getting into the verilog, Xilinx tools, boards and actually making it work?

It started out so promising and turned into useless drivel :-(

[Crom00]

?

Is anyone actually interested in working towards 60Hz capability? Actually getting into the verilog, Xilinx tools, boards and actually making it work?
quote]

Yes would like to see this done, the world does not live on PAL 50hz alone. I'm getting my Mini-Mig next week from australia and will test it on American market LCD and CRT monitors.

[alexh]

Cool, post back when you've got it and I'll work with you to try and get the right crystals, the DCM and the mods to the Agnus

[amigadave]

alexh wrote:
Another MiniMig thread clogged up with non-technical crap. :-(

Does anyone who needs NTSC / 60Hz have a working MiniMig? (not yet, see below)

Is anyone actually interested in working towards 60Hz capability? (YES) Actually getting into the verilog, Xilinx tools, boards and actually making it work? (Willing to learn)

It started out so promising and turned into useless drivel :-(

I hope to have a working Minimig before the beginning of next year.  I don't mind working on and testing changes to the verilog code, but I have no previous experience.  I also will have the parts for a second Minimig, should it become necessary to change the components (crystal(s), etc.) to make a 60Hz NTSC Minimig work.

[Crom00]

For anyone that doesn't have a commodore or 3rd party montior with a 31/15.17 klhz and 50 hz capability you will have a hard time getting Minimig to work.

Most all modern LCD/VGA displays (even multisystem units) display VGA signals starting at 60hz.

I went to local shops in a Northeastern USA major city that caters to european immigrant popluation. They specialize in multisystem tv's/ LCD's I tried the MiniMIG on 4 multi-system LCD's the supposedly supported 50hz and they did not work. The shopkeepers were actually pretty amazed at the MiniMIG and it's homebrew origins.

So I imagine users worldwide will have these problems unless they have an aging Commodore display to use with it.

The whole spirit of MiniMIG is Amiga redone for the 21st century. IF we need to use ancient 50hz monitors for Minimig well that's not going to cut it.

SO this is not really an NTSC issue, it's more of a modern monitor issue. 60z insures compatility with modern LCD's and crt's.

Don't we want to have this on our HDTV's next to the xbox, Wii and Ps3? That's my plan.

So who can execute the changes? Who is willing to do so?
and what's it gonna cost?