+=-=-=-=-=-=-=-=-=-=-=+ | 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 'simkin@innocent.com' +======================================================================+ | 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.