SNES Memory Mapping

]SiMKiN[
                      +=-=-=-=-=-=-=-=-=-=-=+
                      | SNES Memory Mapping |
                      |    By: ]SiMKiN[     |
                      |         v2.0        |
                      +=-=-=-=-=-=-=-=-=-=-=+


 FastROM's can execute at 3.58Mhz
 SlowROM's can only execute 2.68Mhz

   The SNES lets you access ROM through bank $00 onwards and bank 
    $80 onwards such that locations $00:8000 and $80:8000 are congruent,
    (they access the same locations.)
   When accessing bank $00 onwards the 65816 runs at 2.68Mhz. However, 
    when accessing bank $80 onwards the 65816 can run at 2.68Mhz or 
    3.58Mhz depending on how you set bit 0 of $420D.

   This Document Contains Information Regarding ROM's upto 32mbit.
    If you have any information regarding ROM's above 32mbit please send
    E-Mail to [email protected]'

+======================================================================+
| Mode 20: LoROM Memory Model (32k Banks)                              |
| ---------------------------------------                              |
|   $80-$ef : $8000-$ffff                                             |
|              Mirrored to $00-6f                                      |
|   $f0-$ff : $8000-$ffff                                             |
+=========+=============+====================================+=========+
| Bank    | Offset      | Definition                         | Shadow  |
+=========+=============+====================================+=========+
| $00-$2f | $0000-$1fff | LowRAM, shadowed from $7e          |   $7e   |
|         | $2000-$2fff | PPU1, APU                          | $00-$3f |
|         | $3000-$3fff | SFX, DSP, etc.                     | $00-$3f |
|         | $4000-$41ff | Controller                         | $00-$3f |
|         | $4200-$5fff | PPU2, DMA, etc.                    | $00-$3f |
|         | $6000-$7fff | RESERVED                           | $00-$3f |
|         | $8000-$ffff | (Mode 20 ROM)                      | ------- |
+---------+-------------+------------------------------------+---------+
| $30-$3f | $0000-$1fff | LowRAM, shadowed from $7e          |   $7e   |
|         | $2000-$2fff | PPU1, APU                          | $00-$3f |
|         | $3000-$3fff | SFX, DSP, etc.                     | $00-$3f |
|         | $4000-$41ff | Controller                         | $00-$3f |
|         | $4200-$5fff | PPU2, DMA, etc.                    | $00-$3f |
|         | $6000-$7fff | RESERVED                           | ------- |
|         | $8000-$ffff | (Mode 20 ROM)                      | $80-$bf |
+---------+-------------+------------------------------------+---------+
| $40-$6f | $0000-$7fff | RESERVED                           | ------- |
|         | $8000-$ffff | (Mode 20 ROM)                      | $C0-$EF |
+---------+-------------+------------------------------------+---------+
| $70-$77 | $0000-$ffff | (Mode 20 SRAM) 256KBytes           | ------- |
+---------+-------------+------------------------------------+---------+
| $78-$7d | $0000-$ffff | RESERVED                           | ------- |
+---------+-------------+------------------------------------+---------+
|   $7e   | $0000-$1fff | LowRAM                             | $00-$3f |
|         | $2000-$7fff | HighRAM                            | ------- |
|         | $8000-$ffff | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
|   $7f   | $0000-$ffff | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
| $80-$ef | $0000-$ffff | Mirror of $00-$6f                  | $00-$6f |
+---------+-------------+------------------------------------+---------+
| $f0-$ff | $0000-$7fff | RESERVED                           | ------- |
|         | $8000-$ffff | (Mode 20 ROM)                      | ------- |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+

+======================================================================+
| Mode 21: HiROM Memory Model (64k Banks)                              |
| ---------------------------------------                              |
|   $C0-$ff : $0000-$ffff                                             |
|              High Parts ONLY '($8000-$ffff)' are Shadowed to $00-3f  |
+=========+=============+====================================+=========+
| Bank    | Offset      | Definition                         | Shadow  |
+=========+=============+====================================+=========+
| $00-$2f | $0000-$1fff | LowRAM, shadowed from $7e          |   $7e   |
|         | $2000-$2fff | PPU1, APU                          | $00-$3f |
|         | $3000-$3fff | SFX, DSP, etc.                     | $00-$3f |
|         | $4000-$41ff | Controller                         | $00-$3f |
|         | $4200-$5fff | PPU2, DMA, etc.                    | $00-$3f |
|         | $6000-$7fff | RESERVED                           | $00-$3f |
|         | $8000-$ffff | (Mode 21 ROM) from $C0-$EF         | $C0-$EF |
+---------+-------------+------------------------------------+---------+
| $30-$3f | $0000-$1fff | LowRAM, shadowed from $7e          |   $7e   |
|         | $2000-$2fff | PPU1, APU                          | $00-$3f |
|         | $3000-$3fff | SFX, DSP, etc.                     | $00-$3f |
|         | $4000-$41ff | Controller                         | $00-$3f |
|         | $4200-$5fff | PPU2, DMA, etc.                    | $00-$3f |
|         | $6000-$7fff | (Mode 21 SRAM) 256KBytes           | ------- |
|         | $8000-$ffff | (Mode 21 ROM) from $C0-$EF         | $C0-$EF |
+---------+-------------+------------------------------------+---------+
| $40-$6f | $0000-$7fff | (Mode 21 ROM) from $C0-$EF         | $C0-$EF |
+---------+-------------+------------------------------------+---------+
| $70-$77 | $0000-$ffff | (Mode 20 SRAM) 256KBytes           | ------- |
+---------+-------------+------------------------------------+---------+
| $78-$7d | $0000-$ffff | RESERVED                           | ------- |
+---------+-------------+------------------------------------+---------+
|   $7e   | $0000-$1fff | LowRAM                             | $00-$3f |
|         | $2000-$7fff | HighRAM                            | ------- |
|         | $8000-$ffff | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
|   $7f   | $0000-$ffff | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
| $80-$bf | $0000-$ffff | Mirror of $00-$3f                  | $00-$3f |
+---------+-------------+------------------------------------+---------+
| $c0-$ff | $0000-$ffff | (Mode 21 ROM)                      | ------- |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+

 ROM: The SNES ROM Image
 RAM: The SNES Work Memory (WRAM)
       LowRAM, HighRAM, & Expanded RAM 
       All together = 128 Kilo-Bytes
 SRAM: Save RAM (Extra RAM added by Cart)
        The SNES only utilizes 256 Kilo-bits
        However 256 Kilo-Bytes are provided.

 APU: Audio Processing Unit
       SPC700, Inside which has a DSP   
 PPU: Picture Processing Unit
       PPU1: 5c77-01
       PPU2: 5c78-03

 SFX: Super FX Cart Chip, by Nintendo
 DSP: Digital Signal Processing Cart Chip
       a.k.a. 'NEC mUPD77C25'

 Shadow: "Congruent Bank".  Same meaning as Mirror.

          _____________________________________________________
       .o(_Thanx to: zsKnight, Lord Esnes, Y0SHi, and MintaBoo_)o.