Version differences

Nintendo stopped incrementing version numbers after 2/1/3.

There is no known method to programmatically detect 1-CHIP consoles (the known differences are graphical in nature).

See also:

• Errata for a list hardware bugs that affect multiple chip revisions

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:

• 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.
• The INIDISP early read bug does not corrupt tile slivers.

Known bugs:

• Glitches on the first visible scanline on some games that extend VBlank with force-blank.
• Brightness DAC has large rise-time.
• Reports of ghosting
• The output signal is too bright.
• The SNS-CPU-1CHIP-03 motherboard does not output a composite sync signal.

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.

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 PAL 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)

Consoles 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.

References

• Console5 Tech Wiki - SNES - List of Chips, ICs and capacitors for the various SNES motherboards.