INES Mapper 246: Difference between revisions

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m (iNES category sorting)
m ("Zhu Lu Zhi Zhan" is the subtitle of Huangdi, a different game. GoodNES still has them mixed up.)
 
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[[Category:iNES Mappers|246]]
[[Category:iNES Mappers|246]]
  Here are Disch's original notes:
[[iNES Mapper 246]] seems to be a singleton for the Taiwanese game [[wikia:c:bootleggames:Feng_Shen_Bang|封神榜 (''Fēngshénbǎng: Fúmó Sān Tàizǐ'')]].
  ========================
 
   =  Mapper 246          =
It provides 2 KiB of RAM from $6800-$6FFF.
   ========================
 
   Mask:   $FFE7
    
    
    
   $6000-6003:  PRG Regs
  Example Game:
  $6004-6007:  CHR Regs
  --------------------------
  Fong Shen Bang - Zhu Lu Zhi Zhan
 
 
  Notes:
  --------------------------
 
  Regs lie at $6000-67FF, but SRAM exists at $6800-7FFF.
 
  Don't know if there's only 6k of SRAM, or if there's 8k, but the first 2k is inaccessable.  I find the latter
  more likely.
 
 
  Registers:
  ---------------------------
 
  Range,Mask:  $6000-67FF, $6007
 
 
    $6000-6003:  PRG Regs
    $6004-6007:  CHR Regs
    
    
    
    
Line 50: Line 30:
   Powerup/Reset:
   Powerup/Reset:
   ---------------------------
   ---------------------------
   $6003 set to $FF on powerup (and probably reset, but not sure).
   $6003 set to $FF on cold boot. (All other registers probably also, but not required)
 
The present hardware seems to be:
* Four 74LS670 4 x 4bit dual-ported memory
* One GAL16V8
* PRG ROM (up to 2 MiB), CHR ROM (up to 512 KiB), PRG RAM (8 KiB)
* Miscellaneous resistors, diodes, and a battery to power the PRG RAM
 
There is additionally some weird behavior on reads from $FFE4-$FFFF:
* PRG ROM access when A15..A5 AND A2 are all HIGH should instead occur from a bank where PRG A17 is high, i.e. ( [$6003] | $10 )
However, the existing dumps in GoodNES have been pre-patched to not require this.
 
See also:
* http://forums.nesdev.org/viewtopic.php?t=13969 Why does Fong Shen Bang only work in Famiclones?

Latest revision as of 12:12, 2 April 2018

iNES Mapper 246 seems to be a singleton for the Taiwanese game 封神榜 (Fēngshénbǎng: Fúmó Sān Tàizǐ).

It provides 2 KiB of RAM from $6800-$6FFF. 

 Mask:   $FFE7
 
 $6000-6003:  PRG Regs
 $6004-6007:  CHR Regs
 
 
 CHR Setup:
 ---------------------------
 
       $0000   $0400   $0800   $0C00   $1000   $1400   $1800   $1C00 
     +---------------+---------------+---------------+---------------+
     |     $6004     |     $6005     |     $6006     |     $6007     |
     +---------------+---------------+---------------+---------------+
 
 
 PRG Setup:
 ---------------------------
 
       $8000   $A000   $C000   $E000  
     +-------+-------+-------+-------+
     | $6000 | $6001 | $6002 | $6003 |
     +-------+-------+-------+-------+
 
 
 Powerup/Reset:
 ---------------------------
 $6003 set to $FF on cold boot. (All other registers probably also, but not required)

The present hardware seems to be:

  • Four 74LS670 4 x 4bit dual-ported memory
  • One GAL16V8
  • PRG ROM (up to 2 MiB), CHR ROM (up to 512 KiB), PRG RAM (8 KiB)
  • Miscellaneous resistors, diodes, and a battery to power the PRG RAM

There is additionally some weird behavior on reads from $FFE4-$FFFF:

  • PRG ROM access when A15..A5 AND A2 are all HIGH should instead occur from a bank where PRG A17 is high, i.e. ( [$6003] | $10 )

However, the existing dumps in GoodNES have been pre-patched to not require this.

See also:

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