I am working on a project that requires me to relocate an SNES cart port. Did the relocation and tested some games on it and everything works fine EXCEPT games that use the S-DD1 (StarOcean, Street Fighter 2 Alpha,). The games boot up fine but I get garbled graphics. Super FX games work fine and before anyone asks, this is a legit SNES system. Not a clone or anything. I am assuming it is 1 or two the the pins are not getting a proper connection but I can't seem to figure out which one. Everything is tight and nice so I figure one of the wires I used might be messed up or something. Anyway, i figure if there is someone who knows what pins the SDD1 chip accesses directly, it would save me a great deal of time and headache. Thanks ******Disregard the SA1 in the thread title. SA1 games are fine***************** ***update again***** Top Gear 3000 is not working correctly either. It is a DSP 4 chip. Not sure is I have any other DSP games to test...
Ok, so I redid all the wiring but the same problem comes up. Do DSP4/SDD1 games use the same connections as SFX games?
Disabling the CIC (regional lock) breaks SA-1 and S-DD1. You need to enable it and put the wires for the lockout on the extended connector.
^^^ How may I have disabled the lockout? And how do I re-enable it? Do I need to connect the CIC directly to the cart port? Please excuse my confusion. I very much appreciate your reply.
If you connected all pins of the cart slot straight, they're already connected. To disable the CIC people lift it's pin 4 (F411/F413 chip on the mainboard). Just place it back on the board as it was before to re-enable it.
Ahhh I see. I thought your we're implying I somehow disabled the CIC by relocating the cart slot. I have not actually touched the CIC, just the cart slot. Anyway, I doubt it is the CIC because SA1 games work fine. It may have been an issue prior with the SNES...I didn't actually test any special chip games prior to the mod. Do you have any thoughts as to what might be cause this problem(no SDD1 or DSP). I will reiterate, sdd1 and dsp games load fine but give garbled graphics.
It could be bus capacitance/transmission line issues; in general you can't expect for an extended cart slot to work, yet so many people do.
Could be anything, the SDD-1 was unsupported for years in emulation due to it's complexity. Anything that would cause additional latency, including the extra wire length, should be suspect. Edit: I'm assuming you already know what each of these do, Try the other DSP games http://en.wikipedia.org/wiki/List_of_Super_NES_enhancement_chips#DSP-4 It definitely looks like a timing issue.
Very interesting.... I can't help but wonder if maybe my wires are too long. It seems the general consensus has been anything under 6" is fine(mine are at around 5 1/2") but then again i can't say for certain many people are trying SDD1 games, afterall there was only 1 released in the U.S. DSP titles would be the most obvious if that is the case but I think I have only 1 DSP game and it is DSP4. In fact it is the ONLY DSP4 title(Top Gear 3000). Tomorrow is my day off, so I will shorten the wires and see if that helps. If not, I will put the cart slot back, in it's original position, to see if that is the problem. Thanks for all the responses.
Considering the speed in which current moves through a wire, it's technically not LATENCY, as an extension will only add 10s of picoseconds through a few nanoseconds. What's really happening is that the additional capacitance hurts the rise and fall times and for high frequency wires so does the impedance mismatching. You probably should also decouple the power rails closer to the cart, it's possible that these "special" carts are being current starved. Low gauge stranded wire for everything would be best.
