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The motors seem to be just motors? Not stepping motors? With a stepping motor one could do 100 steps, and would then know the exact position. With a normal motor one can just do something like running the motor for 100ms, and hope for the best. Yes, they're just cheap brushed DC motors with plastic...

... The missing IC is a 74'157. If populated, and the two traces on the back cut, it changes the geometry to instead be one 256/256 and two 128/128 games. (in that order) Theoretically pin 15 should be explicitly grounded in order for the '157 to work, but I don't see that, so it may not be function...

uh... pin 1 = Q1 (input) pin 2 = MMC3 PRG A17 (input) pin 3 = Q0 (input) pin 4 = PRG ROM A17 (output) pin 5 = MMC3 CHR A17 (input) pin 6 = Q0 (input) pin 7 = CHR ROM A17 (output) pin 8 = ground pin 16 = +5V pin 9-15 - floating I don't recognize that. It's not any standard 2-, 3-, or 4-input logic ga...

Would you be willing to describe the restrictions on what the program can work with? All I see is an interface to choose one of 4 VRT machines, and and the ability to add ROMs to it, before it generates an image to be flashed to the SPI flash.

PCB says "K-3043" on the back. 74'161 latches A0-A3 74'161 cleared on reset. 74'161 clocked by MMC3 clone /WRAMCE 74'161 latch enable is MMC3 clone /WRAMWE 74'161 Q0 goes to both ROM A17. 74'161 Q1 goes to both ROM A18. 74'161 Q2 and Q3 not obviously connected to anything. This is almost oversize ma...

I have made a cheap-looking diagram to indicate my understanding of the timings. Is this correct? Yes, as far as I can tell. I mean, there's extra details about how there are actually 12 different M2 alignments here (three each at pixel quanta, which shifts from scanline to scanline, and four each ...

If the edges of PA12 don't matter, only the state, then it becomes vital to understand in a real PPU environment how long PA12 stays high during a scanline, and whether or how the random CPU-PPU clock alignment comes into play here. One would need to construct a scanline-wide (with ellipses for mos...

I think everything you want is linked to from FARID's thread here

In my experience, clever-disasm can handle MMC3, but the process involves providing some guidance via an INI file ("there's a jump table here", "this is a datadata table", "this is the bankswitching routine", and so on. Exactly how much depends on how many places the code does things that are harder...

What is the behavior when a target/reload value of $00/$FF is written? Fire IRQ all the time (MMC3-C), once (MMC3-A), never? The value stored in $C000, +1, is the number of scanline detections to generate IRQ. For example, if $C000 = $04, the 5th scanline detected generates the IRQ. Works nicely as...

Do you get any difference in behavior by switching the palette to "pass-through" ?

Something shorted +5V to ground. (That's the only thing that can cause that symptom.)

I suppose you could see how cleanly the card edge connector lines up.

I'm sorry, I really literally can't think of any reason that only one MHROM game would work but a random NROM game wouldn't.

I'd throw a logic analyzer or oscilloscope at it and hope I found something going wrong digitally.


.... well, ok, maybe I'd try replacing the CPU's RAM on the mainboard.

My main problem that I have with the game is the lack of polish. Sure it's kind of fun to play this, but Mario's jump mechanic needs some fine tuning. ... have you replayed the original Super Mario Land any time recently? It doesn't handle very nicely. I mean, you can argue that they should have ch...

Is it consistent with the ÷4 prescaler only getting cleared by writing to $E001 ?