Nintendo 64 RGB DAC Mod (PAL/NTSC ... )
Hey
Introduction:
Normally the N64 is constructed in such a way that only composite video and no RGB signal are generated, with the exception of the FR N64 and some NTSC N64, where it is sufficient to solder a few cables / resistors to be able to use RGB.
All others (especially PAL users) look into the tube :D
Some time ago EvilTim found a way to expand the N64 with an RGB output http://members.optusnet.com.au/eviltim/n64rgb/n64rgb.html
What does the mod bring?
- A wonderful RGB picture 240p / 480i (NTSC), 288p / 576i (PAL)
What kind of RGB cable do I need?
- idr. the RGB cable from the Super Nintendo or a Gamecube cable (with 75 ohms instead of capacitors) is sufficient. But if possible you should buy an original cable, cheap cables from China like you can find them on Amazon or ebay lead to tiles in the picture and hum in the sound, has also been discussed many times in the forum.
What material do you need?
- The main component is a CPLD (EviltTim uses an XC9536XL as PC44 design.)
What is a CPLD?
- CPLD means something like programmable logic chip
- PLCC (~ PC44) means that the chip is plugged into a socket http://en.wikipedia.org/wiki/File:80286_plcc.jpg and not as smd http://de.wikipedia.org/wiki/Quad_Flat_Package as with vqfp
- 44 means that the chip has 44 pinouts
- other data like pin to pin speed (5/10 / 15ns) is not that important.
- Xilinx is the manufacturer, there are also others e.g. Lattice, Alterra, but each manufacturer uses different software, different cables ...
Due to the availability and the low memory of the XC9536, I use the XC9572 XL as a VQFP (as big as a 5 cent piece) (XL = 3.3V instead of 5V). It is also important that you always have the right firmware, you need a different file for each chip. Depending on the design, the pinouts also differ (information can be found in the data sheet). The available INOUTs can be freely assigned with a few restrictions.
Then we need a circuit board, Kynarwire / ribbon cable and the usual soldering equipment.
- Resistors 60x560Ohm + -1% (preferably metal) or like me 24x560Ohm and 18x280Ohm. 2 times 560Ohm in parallel = 280Ohm http://de.wikipedia.org/wiki/Parallelschalt#Widerst.C3.A4nde
- A power supply that supplies 3 V or 3.3 V. (for programming)
- To flash the software you need a "Platform Cable USB" (on ebay from € 30 +) or you can tinker something without hitting the printer port (not recommended).
- With the PLCC44 you need one or better several sockets. e.g. http://www.reichelt.de/PLCC-Sockel/PLCC-44/3//index.html?ACTION=3&GROUPID=3218&ARTICLE=14701&SHOW=1&START=0&OFFSET=16&
- For the connection to the programming adapter pin headers or ...
- 1-2 * 100nF ceramic capacitor
- GameBits for the n64
Here we go:
First you have to unscrew your N64 and remove the heat sinks, it is important that you have a gamebit.
On the circuit board you can see the DencNus (or MavNus) chip right next to the heat sinks, the point (means here is Pin1) should be at the top. You can see that you will be soldering on the left side.
Now the CPLD has to be programmed, either you just solder everything onto a board, which gets very tight with 44 pinouts, or you make a second board to write on like me.
If you use a CPLD other than the XC9572 XL, please check the voltage and pinouts in the data sheet!
First you connect all VCC and all GND (but not VCC to GND! That would be a short circuit)
Then the remaining pinouts to the plug / pin header for the JTAG programmer.
In addition, you need a cable or a plug for the power, important + and- do not interchange Vcc + and GND -. The CPLD must have power for programming.
If you have problems writing, check the pinouts and cables, if necessary solder a ceramic capacitor / electrolytic capacitor between GND and Vcc.
When the cable and programmer are ready, everything is connected to the PC, the orange / red lamp lights up and there is still no power. So connect the power supply, then the lamp should light up green. Next start Impact (Xilinx ISE Design Suite). Everything is recognized. Select any file, write to it, done.
Now we need the board for the N64.
First connect GND and Vcc again, then solder a 100nF ceramic capacitor between Vcc and GND.
Now comes the r2r resistor ladder (the actual D / A), this generates the analog signal (or 3 signals for each color). Orange stands for 560 ohms, purple are either 280 ohms or two 560 ohms in parallel. I would recommend using 280Ohm, it saves space and is scarce anyway.
It's best to sort the exits one below the other (like in my picture), move the second row diagonally by one.
I use silver enamelled wire in 0.4-0.6mm to route the outputs, this is easy to work with and does not break (in contrast to Kynarwire). It is important that you do not connect incorrectly or touch contacts.
When the 3 outputs are ready, you can solder R G B to the AV output by turning the circuit board over and soldering it as shown in the picture.
Finally, the CPLD must be connected to the N64,
The whole thing then looks like this.
Finally, the comparison
RGB:
Composite Video:
FAQ:
- If you are bothered by the shifted RGB image, you can lift the pin for the composite sync on the DencNus and use the sync from CPLD, but composite video is no longer possible.
- If errors occur in the image with composite and RGB, the connections from the N64 to the CPLD (D0-D6, dsync, clock ..) touch.
- If the colors in the RGB images are twisted, you probably connected the RGB ports incorrectly.
- If the RGB image remains black, either the software is wrong, the chip has no power or the inputs are incorrectly connected.
- Attention Kynarwire breaks very quickly where it was soldered, best move / bend as little as possible.
- You should only use multi-core stranded wire for R G B, not much can happen there, otherwise the stranded wire is simply too thick and unwieldy.
- In the case of a circuit board with a socket, the chip can be pulled out of the socket with a screwdriver or CPLD pliers
- You can also use the N64 instead of a power supply unit, simply solder the programming port onto the board and switch on the N64
