Irem H3001 - pinout

[krzysiobal]

Used in games:
* Spartan X 2,
* Daiku no Gen-san 2: Akage no Dan no Gyakushuu,
* Kaiketsu Yanchamaru 3: Taiketsu! Zouringen,
* Ai Sensei no Oshiete: Watashi no Hoshi

This time unfortunatelly only basing on the images of Spartan X2. For furter testing need to wait if one of the above games gets cheaper.
The only quirk is about the unknown ceramic capacitor 331. It seems to go between GND and pin 39, but nothing more is wired to pin 39

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                .--\/--.
          NC ?? |01  48| -> +5V
          NC ?? |02  47| ?? NC       
          NC ?? |03  46| -> CHR-A16
          NC ?? |04  45| -> CHR-A15
     PRG-A16 <- |05  44| -> CHR-A14
     PRG-A15 <- |06  43| -> CHR-A13
     PRG-A14 <- |07  42| -> CHR-A12
     PRG-A13 <- |08  41| -> CHR-A11
         GND -- |09  40| -> CHR-A10
          M2 -> |10  39| ?? to C1  
     CPU-A14 -> |11  38| ?? NC       
     CPU-A13 -> |12  37| -> /IRQ     
     CPU-A12 -> |13  36| -> CIR-A10  
     CPU-R/W -> |14  35| -> CHR-/CE  
 CPU-/ROMSEL -> |15  34| -> PRG-/CE 
      CPU-A2 -> |16  33| ?? NC       
      CPU-A1 -> |17  32| <- PPU-A12  
      CPU-A0 -> |18  31| <- PPU-A11  
     PPU-A13 -> |19  30| <- PPU-A10  
     PPU-/RD -> |20  29| <- CPU-D7  
      CPU-D2 -> |21  28| <- CPU-D6  
      CPU-D1 -> |22  27| <- CPU-D5  
      CPU-D0 -> |23  26| <- CPU-D4  
         GND -- |24  25| <- CPU-D3  
                '------'

[krzysiobal]

Got the Spartan X2 cart, here are my new findings about Irem IF-H3001:

* Register at $9000 has 1Sc mirror abilities::

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$9001:  [MM.. ....]  Mirroring
         ||
         ++- 00=V, 01/11=Single Screen A (CIR-A10 = 0), 10 = H

* Pin 1/2 - does not seem to have any internal connections

* Pin 4 = PRG-A17

* Pin 3 = PRG-A18

* Pin 47 = CHR-A17

* Pin 39 = GND

* C1 is put between /CPU-ROMSEL and GND, not to pin 39

* Pin 33 - this is a delayed copy of M2: rising edge delayed by 40ns, falling edge by 14 ns

* Pin 38 - goes low during read/write cycle at $6000-$7fff (falling edge appears 40ns after rising edge of M2)

* Pins 9, 24, 39 seems to be internally shorted inside CHIP (=GND)

* Reg at $9000 seems to control PRG banking as weel, need to examine it carefuly

[FrankWDoom]

I assume you have seen this but just in case
https://wiki.nesdev.com/w/index.php/INES_Mapper_065

Spartan X2 writes to an undocumented address at least once, $9002 iirc. I did a mmc3 conversion and simply omitted that write and had no consequences as far as I know. Would be interested if you can figure that out.

[krzysiobal]

This is how $9000 works (there are 2 PRG registers, the one at $c000 does not exists at all)

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$9000
[X.......]
 |
 +------ PRG mode
         0: $8000-$9fff = $8000, $a000-$bfff = $a000, $c000-$dfff = {-2}, $e000-$ffff = {-1}
         1: $8000-$9fff = {-2},  $a000-$bfff = $a000, $c000-$dfff = $8000, $e000-$ffff = {-1}

Also, $8001, ..., $8007 are mirrors of $8000
Same with $a001, ..., $a007 for $a000.

Other regs: $9002, $9007, $c000-$c007, $d000-$d007, $e000-$e007, $f000-$f007 does not seem to alter PRG or CHR banking

I also does not observe that mapper has any consistent state upon power-up (like written in that page). It rather keeps the values from before power was cut-out.