82 lines
4.2 KiB
Plaintext
82 lines
4.2 KiB
Plaintext
+=-=-=-=-=-=-=-=-=-=-=+
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| SNES Memory Mapping |
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| By: ]SiMKiN[ |
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| v1.0 |
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+=-=-=-=-=-=-=-=-=-=-=+
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• LoROM: Mode 20
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• HiROM: Mode 21
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• FastROM's can execute at 3.58Mhz
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• SlowROM's can only execute 2.68Mhz
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• The SNES lets you access ROM through bank $00 onwards and bank
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$80 onwards such that locations $00:8000 and $80:8000 are congruent,
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(they access the same locations.)
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• When accessing bank $00 onwards the 65816 runs at 2.68Mhz. However,
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when accessing bank $80 onwards the 65816 can run at 2.68Mhz or
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3.58Mhz depending on how you set bit 0 of $420D.
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+=========+=============+====================================+=========+
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| Bank | Offset | Definition | Shadow |
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+=========+=============+====================================+=========+
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| $00-$2f | $0000-$1fff | LowRAM, each bank is shadowed | $00-$3f |
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| | | From bank $7e | $7e |
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| | $2000-$2fff | PPU1, APU | $00-$3f |
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| | $3000-$3fff | SFX, DSP, etc. | $00-$3f |
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| | $4000-$41ff | Controller | $00-$3f |
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| | $4200-$5fff | PPU2, DMA, etc. | $00-$3f |
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| | $6000-$7fff | Reserved? | $00-$3f |
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| | $8000-$ffff | (Mode 20, 21 - ROM) | ------- |
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+---------+-------------+------------------------------------+---------+
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| $30-$3f | $0000-$1fff | LowRAM, each bank is shadowed | $00-$3f |
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| | | From bank $7e | $7e |
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| | $2000-$2fff | PPU1, APU | $00-$3f |
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| | $3000-$3fff | SFX, DSP, etc. | $00-$3f |
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| | $4000-$41ff | Controller | $00-$3f |
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| | $4200-$5fff | PPU2, DMA, etc. | $00-$3f |
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| | $6000-$7fff | (Mode 21 - SRAM) 256KBytes | ------- |
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| | $8000-$ffff | (Mode 20, 21 - ROM) | ------- |
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+---------+-------------+------------------------------------+---------+
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| $40-$6f | $0000-$7fff | (Mode 21 - ROM) | ------- |
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| | $8000-$ffff | (Mode 20, 21 - ROM) | ------- |
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+---------+-------------+------------------------------------+---------+
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| $70-$77 | $0000-$ffff | (Mode 20, 21 - SRAM) 256KBytes | ------- |
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+---------+-------------+------------------------------------+---------+
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| $78-$7d | $0000-$ffff | Never Used | ------- |
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+---------+-------------+------------------------------------+---------+
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| $7e | $0000-$1fff | LowRAM | $00-$3f |
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| | | Shadowed to banks $00-$3f | ------- |
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| | $2000-$7fff | HighRAM | ------- |
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| | $8000-$ffff | Expanded Ram | ------- |
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+---------+-------------+------------------------------------+---------+
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| $7f | $0000-$ffff | More Expanded RAM | ------- |
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+---------+-------------+------------------------------------+---------+
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| $80-$ef | $0000-$ffff | Mirror of $00-$6f | $00-$6f |
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+---------+-------------+------------------------------------+---------+
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| $f0-$ff | $0000-$ffff | (Mode 21 - ROM) | ------- |
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+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-+
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• ROM: The SNES ROM Image
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• RAM: The SNES Work Memory (WRAM)
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LowRAM, HighRAM, & Expanded RAM
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All together = 128 Kilo-Bytes
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• SRAM: Save RAM (Extra RAM added by Cart)
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The SNES only utilizes 256 Kilo-bits
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However 256 Kilo-Bytes are provided.
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• APU: Audio Processing Unit
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SPC700, Inside which has a DSP
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• PPU: Picture Processing Unit
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PPU1: 5c77-01
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PPU2: 5c78-03
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• SFX: Super FX Cart Chip, by Nintendo
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• DSP: Digital Signal Processing Cart Chip
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a.k.a. 'NEC mUPD77C25'
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• Shadow: "Congruent Bank". Same meaning as Mirror.
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_________________________________________________
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.o(_Thanx to: Y0SHi, zsKnight, MrGrim, and MintaBoo_)o. |