Drakon
Active Member
For people who don't know much about the super fx chips in snes games there's three different versions
the weakest chip is the mario chip which was only found in starfox
the improved chip was the super fx 1 (gsu 1) found in games like stunt race fx and I think vortex
the best chip was the super fx 2 found in doom and some other random games
Overclocking a starfox on its default mario chip is possible but that chip is garbage and doesn't handle overclocking very well. So I got a friend to solder a starfox 1 eprom to a stunt race fx cart
Getting the overclock to work wasn't simple. Removing the resonator and replacing it with a 2 pin crystal either made the game underclock or match the default speed. Even with a 200 mhz crystal it went at the same speed as the 21 mhz resonator. I ended up cutting the clock trace from the super fx chip that connects to the hex inverter circuit. The mario chip starfox cart doesn't have a hex inverter circuit. I wired up a 25 mhz crystal oscillator directly to the super fx clock pin and it finally worked. Here's the video comparing the original cart to the 25 mhz version
I have 3 versions of starfox 1 a mario chip version, a converted stunt race with the super fx 1, and a converted doom with the super fx 2. As expected the doom based starfox handles overclocking the best. I got that cart playing fine at 32 mhz. Unfortunately at 32 mhz starfox 1 goes so fast it freezes at the end of the stage due to it going faster than the programming expects. The game played start to finish no problem at 25 mhz. Tomorrow I'll buy all the oscillators between 25 and 32 mhz and see just how fast it can go. I installed a precision socket so I can easily swap the oscillator.
the weakest chip is the mario chip which was only found in starfox
the improved chip was the super fx 1 (gsu 1) found in games like stunt race fx and I think vortex
the best chip was the super fx 2 found in doom and some other random games
Overclocking a starfox on its default mario chip is possible but that chip is garbage and doesn't handle overclocking very well. So I got a friend to solder a starfox 1 eprom to a stunt race fx cart
Getting the overclock to work wasn't simple. Removing the resonator and replacing it with a 2 pin crystal either made the game underclock or match the default speed. Even with a 200 mhz crystal it went at the same speed as the 21 mhz resonator. I ended up cutting the clock trace from the super fx chip that connects to the hex inverter circuit. The mario chip starfox cart doesn't have a hex inverter circuit. I wired up a 25 mhz crystal oscillator directly to the super fx clock pin and it finally worked. Here's the video comparing the original cart to the 25 mhz version
I have 3 versions of starfox 1 a mario chip version, a converted stunt race with the super fx 1, and a converted doom with the super fx 2. As expected the doom based starfox handles overclocking the best. I got that cart playing fine at 32 mhz. Unfortunately at 32 mhz starfox 1 goes so fast it freezes at the end of the stage due to it going faster than the programming expects. The game played start to finish no problem at 25 mhz. Tomorrow I'll buy all the oscillators between 25 and 32 mhz and see just how fast it can go. I installed a precision socket so I can easily swap the oscillator.
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