Version differences
Nintendo stopped incrementing version numbers after 2/1/3.
S-CPU
S-CPU (5A22-01)
RDNMI version: 1
Known bugs:
- Crashes if a DMA finishes just before HDMA happens
S-CPU A (5A22-02)
RDNMI version: 2
This revision:[1]
- Fixes the DMA/HDMA crash
- Changes the S-WRAM refresh position
- Changes the HDMA setup position
Known bugs:
- A recent HDMA transfer with BBADn=0 can make a DMA transfer fail.
S-CPU B (5A22-02)
RDNMI version: 2
This revision:
- Fixes the DMA failure after a recent BBADn=0 HDMA transfer bug
S-CPUN A (RF5A122)
RDNMI version: 2
Also known as 1-CHIP.
This revision:
- Combines S-CPU, S-PPU1 and S-PPU2 onto a single IC
S-PPU1 (5C77-01)
STAT77 version: 1
There is only 1 known version of the S-PPU1.
It is unknown if the S-PPU1 in a 3-chip console is the same as the PPU1 in the S-CPUN A 1CHIP console.
S-PPU2
S-PPU2 (5C78-01)
STAT78 version: 1
S-PPU2 A (5C78-02)
STAT78 version: 2
This is the rarest revision of the S-PPU2.
S-PPU2 B (5C78-03)
STAT78 version: 3
S-PPU2 C (5C78-03)
STAT78 version: 3
S-CPUN A (RF5A122)
STAT78 version: 3
Also known as 1-CHIP.
Found in 1-CHIP and SNES Jr motherboards.
This revision:
- Combines S-CPU, S-PPU1 and S-PPU2 onto a single IC
- The DAC has been changed and the image is sharper.[2]
- The INIDISP early read bug does not corrupt tile slivers.[3]
Known bugs:
- Glitches on the first visible scanline on some games that extend VBlank with force-blank.[4]
- Brightness DAC has large rise-time.[5]
- Reports of ghosting
- The output signal is too bright.[6]
- The SNS-CPU-1CHIP-03 motherboard does not output a composite sync signal.[7]
Audio
SHVC-SOUND
The first revision of the SNES's motherboard had a separate SHVC-SOUND module.
On motherboard
In 1992 Nintendo moved the SHVC-SOUND chips onto the SNS-CPU-GPM-01 motherboard.
This revision replaces the S-DSP chip with the S-DSP A chip. Any differences between the two revisions are unknown.
S-APU
Found on SNS-CPU-APU-01 and 1CHIP motherboards, the S-APU combines the S-SMP, S-DSP and Audio-RAM into a single S-APU IC.
The S-APU fixes the S-SMP timer glitch.[8]
DAC
Nintendo used 3 different DAC chips:
- NEC µPD6376, in NTSC motherboards dated 1990-1994 (SHVC-SOUND, SNS-CPU-GPM-01, SNS-CPU-GPM-02, SNS-CPU-RGB-01)
- NEC 6376, in motherboards dated 1992 (SNSP-CPU-01, SNSP-CPU-02)
- NEC 6379A, in motherboards dated 1995 or 1997 (SNS-CPU-RGB-02, SNS-CPU-APU-01, SNS-CPU-1CHIP-02, SNN-CPU-01, SNSP-CPU-1CHIP-01, SNSP-CPU-1CHIP-02)
Motherboards with the NEC µPD6376 DAC have a slight audio imbalance. Nintendo tied the 2 Vref pins to a single single 47μF capacitor, while the µPD6376 datasheet shows the 2 Vref pins are supposed to be connected to 2 separate capacitors.[9]
References
- Console5 Tech Wiki - SNES - List of Chips, ICs and capacitors for the various SNES motherboards.
- ↑ ares source code, ares/ares/sfc/cpu/timing.cpp, by Near and ares team
- ↑ 1st-gen Super Famicom / SNES vs. Super Famicom Jr. / SNES Jr by Chris Covell
- ↑ INIDISP Register - INIDISP Early Read Glitch by undisbeliever
- ↑ Demon's Crest 1CHIP glitching comparison by eightbitminiboss (YouTube video)
- ↑ INIDISP Register - Brightness Delay by undisbeliever
- ↑ RetroRGB - SNES 1CHIP Brightness / Signal correction
- ↑ About ConsoleMods Wiki - SNES:SNES Model Differences
- ↑ Forum post: list of version differences by Near
- ↑ ConsoleMods Wiki - SNES:Audio Balance Fix
