                      +=-=-=-=-=-=-=-=-=-=-=+
                      | SNES Memory Mapping |
                      |    By: ]SiMKiN[     |
                      |         v3.5        |
                      +=-=-=-=-=-=-=-=-=-=-=+


 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 48mbit.
    If you have any information not contained in this document please
    send E-Mail to 'simkin@innocent.com'

+======================================================================+
| Mode 20: LoROM Memory Model (32k Banks) - 24Mbit Max                 |
| ----------------------------------------------------                 |
|   $00-$5F : $8000-$FFFF                                             |
|               Mirrored to $80-DF                                     |
|    -------                                                           |
|    $60 * 1/2 banks = 24Mbit                                          |
+=========+=============+====================================+=========+
| 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-$5F | $0000-$7FFF |  RESERVED                         | ------- |
|         | $8000-$FFFF | (Mode 20 ROM)                      | $C0-$DF |
+---------+-------------+------------------------------------+---------+
| $60-$6F | $0000-$7FFF |  RESERVED                         | ------- |
+---------+-------------+------------------------------------+---------+
| $70-$77 | $0000-$7FFF | (Mode 20 SRAM) 256KBytes           | ------- |
|         | $8000-$FFFF |  RESERVED                         | ------- |
+---------+-------------+------------------------------------+---------+
| $78-$7D | $0000-$FFFF |  RESERVED                         | ------- |
+---------+-------------+------------------------------------+---------+
|   $7E   | $0000-$1FFF | LowRAM                             | $00-$3F |
|         | $2000-$7FFF | HighRAM                            | ------- |
|         | $8000-$FFFF | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
|   $7F   | $0000-$FFFF | Expanded RAM                       | ------- |
+---------+-------------+------------------------------------+---------+
| $80-$DF | $0000-$FFFF | Mirror of $00-$5f                  | $00-$5F |
+---------+-------------+------------------------------------+---------+
| $E0-$FF | $0000-$FFFF |  RESERVED                         | ------- |
+=========+=============+====================================+=========+

+======================================================================+
| Mode 21: HiROM Memory Model (64k Banks) - 48Mbit Max                 |
| ----------------------------------------------------                 |
|   $C0-$FF : $0000-$FFFF                                             |
|               High Parts ONLY '($8000-$FFFF)' are Shadowed to $00-3F |
|   $40-$5F : $0000-$FFFF                                             |
|    -------                                                           |
|    $60 banks = 48Mbit                                                |
+=========+=============+====================================+=========+
| 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) 128KBytes           | ------- |
|         | $8000-$FFFF | (Mode 21 ROM) from $F0-$FF         | $F0-$FF |
+---------+-------------+------------------------------------+---------+
| $40-$5F | $0000-$FFFF | (Mode 21 ROM)                      | ------- |
+---------+-------------+------------------------------------+---------+
| $60-$6F | $0000-$7FFF |  RESERVED                         | ------- |
+---------+-------------+------------------------------------+---------+
| $70-$77 | $0000-$7FFF | (Mode 20 SRAM) 256KBytes           | ------- |
|         | $8000-$FFFF |  RESERVED                         | ------- |
+---------+-------------+------------------------------------+---------+
| $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 for MODE 20 SRAM,
        and 128 Kilo-Bytes are provided for MODE 21 SRAM.

 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.