Unique visits: 7754 Can you help getting more info about those carts?

Type multi Mapper 281 Original mapper 0+2 PCB marks 76IN1 Tags: #squaresilk Uploaded: 2023-04-02 08:34:44

             first write        | second write
             addr  hex bin      | addr  hex bin    
             -------------------+--------------------
tetris       $c000 $04 00000100 | $8000 $68 01101000 V
pacman       $c000 $04 00000100 | $8000 $ea 11101010 H
magmax       $c000 $05 00000101 | $8000 $ec 11101100 
super mario  $c000 $05 00000101 | $8000 $6e 01101110
fancy mario  $c000 $05 00000101 | $8000 $ee 11101110

twin bee     $c000 $06 00000110 | $8000 $c8 11001000
battle city  $c000 $06 00000110 | $8000 $8a 10001010
lode runner  $c000 $07 00000111 | $8000 $0b 00001011
contra       $c000 $00 00000000 | $8000 $30 00110000
side pocket  $c000 $00 00000000 | $8000 $90 10010000


contra=3       = prg03
sidepocket=1    = prg04
tetr/pac/mag=2  = prg02
twink bee/menu=0 = prg01

PRG01.nes =
 0 => PRG    25 Japan\TwinBee (J).nes
 1 => PRG    22 Japan\TwinBee (J).nes
 2 => PRG    83 Japan\Battle City (J).nes
 3 => PRG     8 Japan\Lode Runner (J).nes
 4a=> CHR     0 Unlicensed\Tetris (Unl) (U) [p1].nes
 4b=> CHR     0 USA\Ms Pac-Man (U).nes
 5a=> CHR     2 Japan\Magmax (J).nes
 5b=> CHR    70 Unclassified\ZZZ_UNK_w256 (40976).nes
 6a=> CHR   115 Japan\TwinBee (J).nes
 6b=> CHR   130 Japan\Battle City (J).nes
 7a=> CHR    10 USA\Lode Runner (U).nes
 7b=>     MENU
PRG02.nes =
 0 => PRG    90 Unlicensed\Tetris (Unl) (U) [p1].nes
 1 => PRG  1063 Unlicensed\Tetris (Unl) (U) [p2][!].nes
 2 => PRG     0 USA\Ms Pac-Man (U).nes
 3 => PRG     5 USA\Ms Pac-Man (U).nes
 4 => PRG    23 Japan\Magmax (J).nes
 5 => PRG     2 Japan\Magmax (J).nes
 6 => PRG    17 Unclassified\ZZZ_UNK_w256 (40976).nes
 7 => PRG     8 Unclassified\ZZZ_UNK_2600 Bros (SMB1 Hack) (UNL).nes
PRG03.nes = contra (unrom, mirr=v)
PRG04.nes = side pocket (unrom, mirr=h)

------------------------------------
Order of combining: PRG03 + PRG04 + PRG02 + PRG01

PRG-ROM: 512 kB (hovewer A19 is wired to the EPROM)
CHR-RAM:  8 kB

[mvPP .P..] 74*174: $8000-$bfff
 ||||  |  
 ||++--+--- outer PRG (high to low: D0, D5, D4)
 |+-------- mode (0=16kB, 1=32kB)
 +--------- mirroring (0=V, 1=H)

[.... uppp] 74*161: $8000-$9fff and $c000-$dfff 
      ||||
      |+++- inner PRG
      +---- mode (0=UNROM,1=NROM)
yes, it overlaps partially with previous reg, so when wring at $8000-$9fff, both registers are updated

Power up: both registers set to 0
Reset: no change
 
PRG Modes:

uv $8000  $bfff
----------------
00 PPPppp PPP111
01 PPPpp0 PPP111
10 PPPppp PPPppp
11 PPPpp0 PPPpp1
------------------------------------

#include "mapinc.h"
	
static uint8 reg174, reg161;

//shifts bit at position `from` to position `to` in expression
#define shi(exp, from, to) ((((exp) >> (from)) & 1) << (to))

static SFORMAT StateRegs[] =
{
	{ 0 }
};

static void Sync(void) {
	int uv = shi(reg161, 3, 1) | shi(reg174, 6, 0);
	int PPP = shi(reg174, 0, 2) | shi(reg174, 5, 1) | shi(reg174, 4, 0);
	int ppp  = reg161 & 0x7;
	
	switch (uv) {
	case 0: setprg16(0x8000, (PPP << 3) | ppp); setprg16(0xc000, (PPP << 3) | 7); break;
	case 1: setprg16(0x8000, ((PPP << 3) | ppp) & (~1)); setprg16(0xc000, (PPP << 3) | 7); break;
	case 2: setprg16(0x8000, (PPP << 3) | ppp); setprg16(0xc000, (PPP << 3) | ppp); break;
	case 3: setprg32(0x8000, ((PPP << 3) | ppp) >> 1); break;
	}
	setmirror(((reg174 >> 7) & 1) == 0 ? MI_V : MI_H);
	
}

static DECLFW(M281Write) {
	if ((A >= 0x8000) && (A <= 0xBFFF)) {
		reg174 = V;
	}
	if (((A >= 0x8000) && (A <= 0x9FFF)) || ((A >= 0xC000) && (A <= 0xFFFF))) {
		reg161 = V;
	}
	Sync();
}

static void M281Power(void) {
	setchr8(0);
	reg174 = reg161 = 0;
	SetWriteHandler(0x8000, 0xffff, M281Write);
	SetReadHandler(0x8000, 0xFFFF, CartBR);
	Sync();
}

static void M281Reset(void) {
	Sync();
}


static void StateRestore(int version) {
	Sync();
}

void Mapper281_Init(CartInfo *info) {
	info->Power = M281Power;
	info->Reset = M281Reset;
	
	GameStateRestore = StateRestore;

	AddExState(&StateRegs, ~0, 0, 0);
}

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