NTSC MiniMig

[freqmax]

If the only physical change is to swap the crystal. Maybe a change should be incorperated such that both clock sources (pal=4.433619 ntsc=3.579545) are available to the fpga..?

That way changes between pal/ntsc is just software and no soldering iron fixing.

The clock circuit is quite simple:
IC8 74HC40670
C54 100nF
R55 1Mohm
R54 2.2kohm
C48 100pF
X1 Crystal 4.433619 or 3.579545 MHz
C47 22pF

Just duplicate it and wire up another pin on the fpga besides Pin 80.
It might also be useful if the MCU could provide the pcb version such that the verilog sources can reconfigured at runtime. (or some serial i2c-eeprom).

[freqmax]

What about this, let's have the S-video encoder pcb solder pads on the board. And those that want it can simply solder the circuits. The extra space should be neglible.

Alternativly if a breakout board is made for flatcable stuff. One can put it on the breakout board.

Hmm.. maybe DB23M can be recreated with pins and epoxy
Just plug loose connectors to pins in an existing db23 and swipe with oil/grease. Then pour epoxy over it  :-)

[freqmax]

I have created a Minimig wiki:
http://www.opencircuits.com/Minimig_NTSC - NTSC Issues
http://www.opencircuits.com/Minimig_Project

My hope is that it will help people to accumulate knowledge in this matter such that one doesn't have to read long.. threads to find information.
Especially now that there are several.

No login required, works almost like wikipedia.

[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.

[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"..