It took 5 days of tinkering and 2 months of waiting but i finally did it. I wanted to experience NTSC SNES games in their native speed so the SuperCIC felt like a great solution..... until i've discovered that i got a 1chip model. This isn't so bad as it turned out that as the 1chip has a superior video quality over RGB. Sadly I've bought the electronics stuff before checking which model i had so the project was stopped 2 months ago as the SuperCIC is not enough as the system clock frequency also needs to be switched out.
The reason for the waiting was this magnificent circuit made by ikari. It's basically two pierce oscillators with some glue logic to switch between the clock signals. For random reasons no bigger consumer electronics stores like Reichelt, Farnell or Conrad which are a common source for circuit stuff around here have the very specific and needed NTSC crystal in their supply.
21.47727 MHz ... argh... this number is like a nightmare.
I had to order it from Hong Kong as i didn't wanted to pay 20€ for ordering at an industrial vendor. My last post was about that.
After putting everything together and fixing some bugs here and there the solution looked like this:
I don't have any photo of the underside and i don't want to peel the board off again so here is the early design from eagle.
Next to the oscillators is a 74HC00 which selects the wanted frequency. On the left we have a PIC16F630 implementing the SuperCIC from ikari and a PIC16F684 for the borti4938 variant of the IGR. It was suggested by ikari to skip his original solution in favour of that one.
The workings on the main board were inspired by wolfsofts article.
For minimal wiring sizes i used small lacked copper wires.
After doing this mod i was curious how it would harmonize with the sd2snes. Well it didn't...... at first.
The current stable firmware of the sd2snes is 1.6.0 which proudly detects the SuperCIC in the system information but doesn't makes use of it.
The experimental release 1.7.4 preview 4 is the first one to utilize the "pair mode". I installed it and configured it to enable this mode. Still it only works if you set the uIGR correctly.
It saves the last configured region mode so if you forced PAL or NTSC or maybe enable the "normal" auto region detection it will not work.
Press L + R + Select + Pad Left (or Pad Right) to set the uIGR to "detect region from SCIC". If this setting is not changed after that the region from the ROM is transfered from the sd2snes to the SuperCIC and then to the uIGR as soon the game is loaded.
The is also indicated by the LED as Green means PAL and Red NTSC.
I only did this for testing as a revert to 1.6.0 seems to be a better option for me at the moment. I will wait until the official release of 1.7.4 as the menu is a little bit bugged out.... and the sd card seems to be written every second which is scary. :-O
L + R + Select + Y to force PAL / 50 Hz
L + R + Select + A to force NTSC / 60 Hz
L + R + Select + Start to reset the game
L + R + Select + X reset into the sd2snes menu. (I love this!)
After everything was finished I've discovered the guy named borti4938 has created a more clean solution. If i had discovered that early i would have used that too.....
Source of picture
But hey. My board seems to be a little bit dirty but i decided it would be smart having the PIC controllers socketed. I'm ready for future firmware changes ;-)
If you like your SNES this mod is a really good one.