Unique visits: 7991 Can you help getting more info about those carts?

Type multi Mapper Original mapper 0+2 PCB marks N76A-1 Tags: Uploaded: 2021-05-27 12:12:15

Quite strange cartridge - NROM+UNROM multicart (it consist of 2 UNROM games - Contra and Rockman)

[code]
[....mwab] @ $6000 (mask: $E001)
     ||||
     ||++-- PRG mode: 00=NROM 16k, 01=NROM 32k, 10=UNROM, 11=FIXED
     |+---- CHR-RAM writes: 0=allowed, 1=denied
     +----- mirroring: 0=V, 1=H

[.QQQQPPp] @ $6001 (mask: $E001)
 
[.....ABC] @ 8000 (mask: $8000)

ab |  $8000  |  $c000
00 | QQQQPPp | QQQQPPp
01 | QQQQPP0 | QQQQPP1
10 | QQQQABC | QQQQ111
11 | QQQQ111 | QQQQ111
[/code]

[b]1.[/b] The mapper functionality is integrated inside a blob instead of discrete chips.
            +------+
 PRG A20 <- |01    |
 PRG A19 <- |02    |
 PRG A18 <- |03  30| -- VCC
 PRG A17 <- |04  29| -> WR $6001
 PRG A16 <- |05  28| <- PPU A11
 PRG A15 <- |06  27| <- PPU A10
 PRG A14 <- |07  26| -> CIRAM A10
 PRG /CE <- |08  25| <- CPU R/W
      M2 -> |09  24| <- CPU /ROMSEL
 CPU A13 -> |10  23| <- CPU D0
 CPU A14 -> |11  22| <- CPU D1
      J3 -> |12  21| <- CPU D2
 CHR /WE <- |13  20| <- CPU D3
 PPU /WE -> |14  19| <- CPU D4
     GND -- |15  18| <- CPU D5
      J1 -> |16  17| <- CPU D6
            +------+
[/code]
* J3 (pin 12) - it is connected via jumper to CPU A0 (but there is a place for resistor a diode to perform OR between PPU A13 and CPU A0; when those elements are soldered (and the jumper cut), every game hangs after selected from menu. 
[code]
PPU A13 --|>|-+---
CPU A0  -+-R--+
         |    |
         +-J3-+
		(Closed)
[/code]

* J1 (pin 16) - unknown input (there is an open jumper on it to PPU A13); not pulled up to anything but shows some kind of connection inside; applying 0/1 does not alter behaviour
* J2 (pin 29) - there is an open jumper on it to GND, but it is output (!). It is cleared on power up (or after reset occurs). Goes high after the first write to $6000 (exactly - when M2 goes down)value does not matter)



[b]2.[/b] CHR-ROM is SO28 (with mixed address lines)

[b]3.[/b] PRG-ROM is extra large blob (2 MB), but has a weird pinout, it does not resemble any 16 bit EPROM pinout at all.
[code]
            +------+
 CPU A6  -> |01    |
 CPU A5  -> |02    |
 CPU A4  -> |03    |
 CPU A11 -> |04    |
 CPU A12 -> |05  36| <- CPU A7
 PRG A19 -> |06  35| <- CPU A8
 CPU A3  -> |07  34| -- VCC2
 CPU A2  -> |08  33| <- CPU A9
 CPU A1  -> |09  32| <- CPU A10
 CPU A0  -> |10  31| <- PRG A18
   GND1  -- |11  30| <- PRG A17
 CPU D0  <- |12  29| <- PRG A14  
 CPU D1  <- |13  28| <- CPU A13
 CPU D2  <- |14  27| <- PRG /CE2?
 CPU D3  <- |15  26| <- PRG /CE
   VCC1  -- |16  25| <- PRG A16
 CPU D4  <- |17  24| <- PRG A15
 CPU D5  <- |18  23| -- GND2
 CPU D6  <- |19  22| -> UNKNOWN OUTPUT (at 0V)
 CPU D7  <- |20  21| <- PRG A20
            +------+
[/code]

* It has J0 jumper on PIN 27 (shorted to GND), but when shorted to VCC, it becomes open bus, so it must be /CE2
* There are 2 GND lines (intternally shorted)
* There are 2 VCC lines (not shorted internally). I think one might be VCC and the other /WE
* There is also one unknown output (pin 22), going to via-to-nowhere
I think this blob might be in fact some kind of Flash  memory
 
[b]4.[/b] Cartridge requires M2 toggling, otherwise (29ms after M2 stops toggling), the mapper goes into reset mode and writes does not have any effect (and there are no external reset detector)

[b]5.[/b]I found somewhere on the internet cartridge with the same menu but a little different game list

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