Emulate Nintendo DS card via DE1 GPIO pins

[Altera_Forum]

Hi guys, I'm trying to emulate a very simple Nintendo DS card through the GPIO pins on a DE1 board. I'm familiar with the Nintendo DS card protocol, though I'm still a newbie regarding digital logic/electronics. 

 So far I've taken apart a Nintendo DS card and soldered on wires for all the card pins which I can connect to the DE1 GPIO pins.   Interested readers can find a pinout for the DS card at http://www.bottledlight.com/ds/index.php/hardware/dscardport or http://nocash.emubase.de/gbatek.htm#auxdsgamecardslot.  Now I'm trying to see what the DS is sending over the CLK and DATA lines using the builtin SignalTap logic analyzer in Quartus, but so far these lines are not changing at all and I can't figure out why (I tested all lines with a meter and they are fine).  I'm still new to digital logic and electronics, so I am not sure what to do with the GND and 3.3V power signals the DS supplies and connecting them to the FPGA GPIO pins.  Do I need to connect the DS card GND to the GPIO pin GND? And where do I need to connect the DS card 3.3V power signal to in the GPIO pins? Can I ignore this signal?  Thanks in advance

[Altera_Forum]

Very interesting project do you have here... 

 I suppose the 3.3V are for powering out a DS card. In this case, as you have an already powered board, you can leave it unconnected. The GND pins should be connected, however, or you will have floating grounds. Check also the voltage levels of any I/O going from/to the FPGA when making pin assignments in Quartus.

[Altera_Forum]

Yeah, this is going to be a really fun project :). 

 I let the power signal coming from the DS float, and connected the ds card gnd signal to the DE1's GPIO_1 GND.  In the assignment editor in Quartus, the I/O standard for all pins is set to 3.3-V LVTTL, I think this is correct.  Though, still no dice :(.

[Altera_Forum]

Good news! 

 I finally managed to get some good output from the DS card pins.  It looks like it was working all along. In my first attempts, my SignalTap trigger was capturing signal data at the wrong time, because of noise when the Nintendo DS boots.  I use a better trigger now, and signals are getting through nicely.  Now it's just a matter of time before I can emulate a real Nintendo DS card :).