N-SPC Engine/Nintendo

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If you're looking for Super Mario World or Pilotwings, see the Prototype variant instead.

NOTE: The following page is a stub, and is under construction.

Nintendo is the first user of the N-SPC engine, both at launch and with the prototype variant. There are a variety of game-specific or programmer-specific cases in here, and thus have been sorted accordingly.

The raw build sorting notes can be found here for all variants by Nintendo.

TODO most other Nintendo games

F-Zero

This is the first released game to use the standard N-SPC VCMD set starting at $E0. VCMDs $FB-$FF don't exist, though, and the fast forward phrase commands also don't exist here.

Game Name	VCMD Table Location ($E0 and up)	ROM Offset
F-Zero	0x0EE9, relative to 0x0E29	0x01E538 (US & Japanese versions) 0x01841E (European version)

Communication with the SNES

Each CPUIO register has its own individual usage.

CPUIO0 ($2140/$F4)

Command ID	Description
%xyyzzzzz	Play Music/Looping SFX/Second Engine Control
$FF	Load New Data

Play Music/Looping SFX/Second Engine Control (Command $00-$FE)

Input

%xyyyzaaa

Output

%00000aaa

• x, when set, fades out the music over 84 tempo ticks. It causes music VCMD $F5 (echo enable bits and volume) to effectively act as a NOP when this happens.
• yyy is a looping SFX ID for channel 6, with a range of %001($1)-%100($4), and looping back to $1 after $4. Except for $3, they also don't restore the instrument ID after playing them.
• z, when set, causes the BRR engine noise generator from $2143/$F7 to output on channels 4-7.
• aaa is a music ID that is output to the SNES via $2140. %110($6) is a special case, as it utilizes an ID that is defined via loading a single byte to a specific memory location, rather than its own (the ID itself is illegal if forced due to a zero pointer). Music data does not actually need to be loaded in this particular case, as it is all stored in one go.

Load New Data (Command $FF)

Loads new data when set to $FF. See the source build's Load New Data command for the loading protocol, as it is identical binary-wise to the copy used in this one minus the *Ver S1.20* string.

CPUIO1 ($2141/$F5)

Input

%xyzzzzzz

Output

%00zzzzzz

• x increases the overall BRR engine noise generator frequency on channel 8. The BRR engine noise generator frequency is designed to hiccup like a gearshift when activating.
• y plays a continuous beeping tone on channel 6... unless the music that's currently playing is $11, which means a different SFX plays on channels 6 and 8.
• zzzzzz controls the BRR engine noise generator frequency on channel 8. Disable with zero. This value is what is output to the SNES via $2141.

CPUIO2 ($2142/$F6)

%xyzzaaaa

The value output to the SNES via $2142 is which bits are being utilized to play the SFX. Higher bits have more priority, but CPUIO0's channel 6 SFX has higher priority, which in turn is out-prioritized by CPUIO1's channel 6 SFX.

• x stops the music and goes BOOM! Channels 3-8 are used, with 5-8 being continuously used afterwards.
• y plays a UFO-like SFX on channel 6.
• zz controls the BRR engine noise with vibrato on channel 6.
• aaaa controls incidental SFX on channel 6. $4 doesn't play anthing, and the values wrap around to $1 after $8, except for $C, which plays $8.

CPUIO3 ($2143/$F7)

Input

%xxxxyyyy

Output

%0000xxxx

• xxxx controls the panning of the second vehicle on channel 7, with zero representing left and $E representing right. Sets up a whole bunch of vehicle noises on channels 4-7 if set to $F instead that are not pitch-controllable. These bits are output to the SNES via $2143 as the lowest four bits.
• yyyy controls the BRR engine noise generator frequency (and volume) of the second vehicle on channel 7, or several at once on channels 1-5 and 7 if bit z on $2140/$F4 is set.

SFX Sequence Format

Most of the SFX is hard-coded and the instrument format, when utilized outside of the actual instrument table, is identical to a music instrument's. The only SFX that actually uses a SFX sequence format beyond an array of notes is CPUIO0's bit yyy ID %010 ($2) (there's actually a second one defined, but it appears to never have been used). These are headerless, unlike a song, and they only support one channel at a time, with the channel used being fixed.

VCMD ID	Description	Arguments
$00	End of SFX
$01-$7F	Note Duration	(xx)
$80-$C7	Note
$C8	Tie
$C9	Rest
$CA-$DF	Percussion
$E0	Instrument	xx
$E1-$FE	Invalid Note
$FF	Restart SFX

End of SFX (VCMD $00)

Terminates the SFX.

Note Duration (VCMD $01-$7F)

%0xxxxxxx (yy)

• xxxxxxx represents your note length (as seven bits) in tempo ticks.
• yy, if less than $80, represents the volume of the note.

Note (VCMD $80-$C7)

Plays a note and delays the channel for one note length before reading another VCMD.

Tie (VCMD $C8)

Continues playing the previous note and delays the channel for one note length before reading another VCMD.

Rest (VCMD $C9)

Keys off the previous note and delays the channel for one note length before reading another VCMD.

Percussion (VCMD $CA-$DF)

Plays a percussion note.

By default, percussion uses the same instrument set as the song, and all percussion is keyed on with a note of $A4. Note that there is no way to define the base instrument ID used for percussion for the SFX, so it is bound to the music's base instrument ID for percussion instead.

Instrument (VCMD $E0)

$E0 xx

• xx is an instrument ID to an array of instruments. The array used is the same one used for the music.

Invalid Note (VCMD $E1-$FE)

Doesn't crash the sound driver, but does play an invalid note.

Restart SFX (VCMD $FF)

Restarts the SFX from the beginning.

Aging Cassette/Sound Module and Burn-In Test

Game Name	VCMD Table Location ($E0 and up)	ROM Offset
Aging Cassette/Sound Module and Burn-In Test	0x0EE9, relative to 0x0E29	0x0380BA (Aging Cassette) 0x038792 (SNES Burn-In Test Cartridge)

Voice Command Format

TODO new music VCMDs (the standard set is offset backwards by two IDs, and three new VCMDs are added on)

Communication with the SNES

TODO identical to standard Kankichi/N-SPC except for new commands at $80, $90-$93, of which $80 does $90-$93's commands as well as provide output


TODO all other Nintendo variant games (that aren't known to be associated with other Nintendo variant games and likely have sound driver command differences between each other)