Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips)

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krzysiobal
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Location: Poland

Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips)

Post by krzysiobal » Tue Jun 20, 2017 3:31 pm

In case anyone would like to rev-en. Unfortunately those photos are not mine, I waited half of year for one man to take them for me.

Top:
Image Image Image Image Image Image Image Image Image Image Image Image Image

Bottom:
Image Image Image Image Image Image Image Image Image Image Image Image

Shell:
Image Image Image Image Image Image Image Image Image Image
Last edited by krzysiobal on Sun Oct 22, 2017 4:17 am, edited 1 time in total.

zxbdragon
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by zxbdragon » Tue Jun 20, 2017 3:45 pm

this mapper 106,two version dumped rom.

lidnariq
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by lidnariq » Tue Jun 20, 2017 4:07 pm

Parts:
74LS161 74LS04 74LS670 74LS32
74LS161 74LS670 74LS670 23C1024
74LS74 74LS670 74LS374
74LS74 74LS32 74LS374
74LS138
74LS20 74LS157 GM76C88 23C1024 23C1024
4040 74LS86
74LS393 74LS00
74LS32 74LS74 74LS32 74LS08

Findings:
Presence of 4040 and 76C88 means this is not a N108 clone. There is some kind of IRQ source (the 4040) and PRG RAM (the 76C88)

Edit: Summarizing FCEUX's mapper 106 code:
Register mask: $800F.
Writes to $8000 through $8007: Set eight 1 KiB CHR banks. Bottom four banks deny use of LSbit, like MMC3, but allow upper 7 bits to be set differently.
Writes to $8008 through $800B: Set four 8 KiB PRG banks. Banks at $8000 (reg $8008) and $E000 (reg $800B) force $10s bit high.
Write to $800C: Identical to MMC3 $A000 mirroring control
Write to $800D: Acknowledge and disable IRQ
Write to $800E: Set upper byte of 16-bit terminal count
Write to $800F: Set lower byte of 16-bit terminal count, and enable counter. Counts M2 cycles.

I'm not entirely convinced the enumerated parts match the functional description. I don't think I see enough possible simple logic to compare every bit of the 4040's output against latches.

ZenoTasedro
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by ZenoTasedro » Mon Jun 26, 2017 11:23 am

That is awesome AF

krzysiobal
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by krzysiobal » Fri Sep 01, 2017 5:03 pm

I got the mapper 106 SMB3 version:
Image Image Image Image Image

Probably the one from first post is unmodified SMB3.

zxbdragon
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by zxbdragon » Fri Sep 01, 2017 10:48 pm

this mapper 106 or 56

krzysiobal
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by krzysiobal » Sat Sep 02, 2017 3:47 am

zxbdragon wrote:this mapper 106 or 56
Yes, this is mapper 106. This version works only in NTSC/Dendy mode.
What is mapper 56, as FCEUX does not have it implemented?

zxbdragon
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by zxbdragon » Sat Sep 02, 2017 4:03 am

mapper 56 is KAISER_KS7022C or KAISER_KS202

ines or nes 2.0 is Chicken ribs!

krzysiobal
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Location: Poland

Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by krzysiobal » Fri Oct 20, 2017 1:07 pm

After a lot of days spend on rev-in this based only on those diffrent angle photos, I got the following results, but I would like to ask for help rev-ing out the interrupt part as not all connections are probably OK (other parts are 100% certain)
Image Image Image

PRG banking, CHR banking, mirroring works exactly the same way like in MMC3 (which is really rare), with the exception that bit 7 and bit 6 of bank select register are trated as if b7=0 (CHR A12 inversion off) and b6=1 ($C000-$DFFF swappable, $8000-$9FFF fixed to second-last bank), but I think original SMB3 always uses the configuration above. (I dont have access to ROM of this bootleg so I don't have idea if the game was modified and how much). I think that probably the game was not modified at all, that's why the mapper is so much similar to MMC3.

Now the tricky part - interrupts and counters. This probably does not work in the same way as in MMC3 because there is only one 8 bit counter (2x74191) which is both preloaded and counted down. But again, as I have observed, original SMB3 preloads IRQ counter every frame in NMI.

I have doubts if all connections of interrupt part are OK (other parts are 100% ok).
Except those 2x74191 there is 4040 and 2x74393. Outputs of 4040 are connected to inputs of 7420 (those connections are certain).

I don't even know what is clocking this bootleg's counter. There is one modification on this PCB:
Image

So they put R+C instead on PPU-!A12 (probably some kind of filter, maybe they wanted to filter out those 8 consecutive edges on PPU_A12) - i dont know value of C, only R can be read.

Next modification is cut trace on IC3A input 5 (probably slight change in prescaling)

However, this filtered PPU-!A12 does not seem to be clocking the unit, it's probably ANDED with cpu-romsel (inverted cpu-!romsel from the connector) but this is not 100% sure as critical tracks are under chips and only deduction is available.

lidnariq
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by lidnariq » Fri Oct 20, 2017 1:38 pm

krzysiobal wrote:There is one modification on this PCB [...] So they put R+C instead on PPU-!A12 (probably some kind of filter, maybe they wanted to filter out those 8 consecutive edges on PPU_A12) - i dont know value of C, only R can be read.
That's a highpass filter, not a lowpass filter. Wouldn't be suitable for filtering a PPU signal to generate a clock per scanline.
However, this filtered PPU-!A12 does not seem to be clocking the unit, it's probably ANDED with cpu-romsel (inverted cpu-!romsel from the connector)
I can't fathom any reason to AND /PPUA12 with /ROMSEL. The phase from sprite tile fetch to the next will end up clocking the counter one or two times:

Code: Select all

/PPUA12 ~~~~~~~~~~~~____~~~~____~~~~____~~~~
/ROMSEL ~__~__~__~__~__~__~__~__~__~__~__~__
    AND ~__~__~__~________~_____~__~_____~__
... maybe there's something clever such that that always ends up the same integer, and not 113+2/3 ?

I can't figure out how the half of the 74'393 that you've labelled IC1A would ever let the '4040 run at all. (Every 8 clocks it'd clear the '4040?)

Could you annotate over the IRQ section of your schematic what parts you're confident of vs not?

MLX
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by MLX » Sat Oct 21, 2017 7:04 am

I have this variant, if you're unsure about some traces I can check them with my multimeter. Also can dump it with kazzo. I *think* I tried at a point to dump it with MMC3_v2 but it didn't work? I need to check again.

krzysiobal
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by krzysiobal » Sat Oct 21, 2017 8:05 am

That would be really great, could you please chceck those connections (chip name.pin name)

1) IC25.12 == IC28.11
2) IC25.13 == R3.2
3) IC25.11 == IC1.13
4) IC25.11 == IC1.1
5) IC25.11 == IC2.10
6) IC1.6 == IC15.5
7) IC1.6 == IC28.9
8) IC6.9 == IC4.9
9) IC1.9 == IC6.10
10) IC5.10 - does connect to any of IC25 pins?
11) IC1.12 - any other pins it connect to?
12) IC1.2 - any other pins it connect to?


If you cend me mmc3_v2, then I can modify it to work with this game.

MLX
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by MLX » Sat Oct 21, 2017 8:17 am

You can find the mmc3_v2 script in the kazzo file library.
I'll try it tonight if I have time. I'm not a techy person so I may get lost a bit with your drawing heh.

krzysiobal
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Location: Poland

Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by krzysiobal » Sat Oct 21, 2017 8:31 am

MLX wrote:You can find the mmc3_v2 script in the kazzo file library.
I'll try it tonight if I have time. I'm not a techy person so I may get lost a bit with your drawing heh.
Just use the chip & pin numbers from this photo:
Image
Attachments
mmc3_smb3_asian.zip
(982 Bytes) Downloaded 213 times

lidnariq
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Re: Photos of SMB3 PCB (MMC3 entirely on discrete 74xx chips

Post by lidnariq » Sat Oct 21, 2017 12:19 pm

MLX wrote:I *think* I tried at a point to dump it with MMC3_v2 but it didn't work? I need to check again.
The default Kazzo script tries to switch the MMC3 into 8+8+16F mode, which Krzysiobal says isn't supported by this hardware, so... that's probably why.

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