322 lines
9.8 KiB
Plaintext
322 lines
9.8 KiB
Plaintext
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VRCVII CHIP INFO
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------ ---- ----
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By:
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Kevin Horton
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khorton@iquest.net
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The RENES Project:
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Reverse-engineering
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the world.
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V0.10 11/05/99 Document started, pinned out chip and audio thingy
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V0.20 11/10/99 Added very, very, very preliminary register findings
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v1.00 11/14/99 First release version of this doc
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VRCVII (VRC7) (48 pin standard 600mil wide DIP)
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-------------
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This chip is used in only one Konami game that I know of- Lagrange Point.
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I heard rumours it was used in another game, so if someone could provide
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info and/or a ROM image, that would help immensely. It handles ROM
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bankswitching as well as sound generation. The sound generation is done
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using FM synthesis, so the music sounds like "Adlib" OPL2 music. Due to
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extra sound, this is a Famicom-only chip like its cousin the
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VRCVI. (See the VRCVI doc for more info)
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"VII" of "VRCVII" is "7" for the roman numeral challenged.
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This chip appears to generate all of its audio internally, which is then
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fed to a small hybrid (aka "black blob") that does the audio interfacing
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to the Famicom proper. It is physically a small ceramic substrate with
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an 8 pin SMD chip on it (probably an op-amp), and what appears to be three
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0805 sized SMD chip parts (capacitors most likely, since resistors can be
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formed on the substrate). The whole works is then coated with a black
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dipped epoxy coating, and the smooth side (opposite the parts) is then
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marked with an identifying part number and the pin 1 dot.
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Here's the pinout for it:
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Front Side (parts facing away)
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+-----------------+ 1- Audio in from Famicom
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| 054002 | 2- Audio out to Famicom
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|@ | 3,7 - Ground
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+-----------------+ 4-6 - NC
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| | | | | | | | | 8- Audio from VRCVII
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1 2 3 4 5 6 7 8 9 9- +5V
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Legend:
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-------
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(s) means this pin connects to the System
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(r) this only connects to the ROM
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(w) this is a SRAM/WRAM connection only
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PRG : these connect to the PRG ROM and/or fami's PRG pins
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WRAM : this hooks to the WRAM
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Note: There is a 3.58Mhz ceramic resonator connected to the "X1" and "X2"
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pins. it is the three-pin style with internal caps tied to the third pin
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which is grounded.
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Chip is physically marked: "VRV VII 053982"
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.----\/----.
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*1 (RAM&s) CHR /OE - |01 48| - NC
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*1 (RAM&s) CHR /CE - |02 47| - M2 (s)
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GND - |03 46| - /CE WRAM (w)
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(s) R/W - |04 45| - PRG /A15 (s) (aka /CE)
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(s) /IRQ - |05 44| - PRG ROM /CE (r)
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(s) CIRAM A11 - |06 43| - Audio Out
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(s) PD0 - |07 42| - +5V
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(s) PD1 - |08 41| - NC
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(s) PD2 - |09 40| - NC
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(s) PD3 - |10 39| - NC
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(s) PD4 - |11 38| - NC
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(s) PD5 - |12 37| - NC
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(s) PD6 - |13 36| - CHR RAM A12
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(s) PD7 - |14 35| - CHR RAM A11
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+5V - |15 34| - CHR RAM A10
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(s) PRG A5 - |16 33| - CHR A12 (s)
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Crystal X2 - |17 32| - CHR A11 (s)
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Crystal X1 - |18 31| - CHR A10 (s)
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(s) PRG A4 - |19 30| - +5V
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(r) PRG ROM A13 - |20 29| - PRG A14 (s)
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(r) PRG ROM A14 - |21 28| - PRG A13 (s)
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(r) PRG ROM A15 - |22 27| - PRG A12 (s)
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(r) PRG ROM A16 - |23 26| - PRG ROM A18 (r)
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GND - |24 25| - PRG ROM A17 (r)
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`----------'
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VRCVII
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*1: these connect to both the CHR RAM's pins and the card edge.
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Note: the NC pins 37-41 most likely for CHR ROM bankswitching. Since this
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cart uses CHR RAM these obviously weren't used ;-)
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Registers: (sound related only)
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----------
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All sound registers are accessed through only two physical registers.
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9010:
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-----
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This is the index register. You write the desired register number here.
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9030:
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-----
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This is the data register. Data written here is stored in the register
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pointed to by the above index register.
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There are 6 channels, each containing three registers, and 8 custom
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instrument control registers.
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Sound Registers:
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----------------
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00h - 07h : Custom instrument registers. See below for info.
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---
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10h - 15h : ffffffff
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f: Lower 8 bits of frequency
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---
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20h - 25h : ???tooof
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f: Upper bit of frequency
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o: Octave Select
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t: Channel trigger.
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?: Dunno what these do yet (No audible effect)
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---
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30h - 35h : iiiivvvv
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i: Instrument number
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v: Volume
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Instrument numbers 01h-0fh are fixed and cannot be changed.
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Instrument number 00h is the "programmable" one.
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To program the custom instrument, you load registers 00h-07h with the
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desired parameters for it. All channels set to instrument 00h will
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then use this instrument. Note that you can only program one custom
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instrument at a time.
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How do the frequency registers work?
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------------------------------------
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To generate a tone, you must select an octave and a frequency value. The
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frequency values stay the same for say, the note "C", while the octave
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bits determine which octave "C" lies in. This makes your note lookup table
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quite small.
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o = 000 is octave 0
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o = 001 is octave 1
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.
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.
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.
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o = 111 is octave 7
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49722*freqval
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F = -------------
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2^(19-octave)
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Where:
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F = output frequency in Hz
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freqval = frequency register value
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octave = desired octave (starting at 0)
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Custom Instrument Registers (00-07)
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-----------------------------------
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Note: I will not provide too extensive documentation of the instrument
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registers since their functions are identical to those of the OPL2 chip,
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commonly found on Adlib/Soundblaster/compatible cards, and there is alot
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of information out on how to program these. I will use terminology
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similar to that found in said documents. My VRC7 "emulator" test program
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I wrote simply re-arranged and tweaked the register writes to correspond
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with the OPL2 registers.
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Here's a link to a good document about this chip:
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http://www.ccms.net/~aomit/oplx/
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The tremolo depth is set to 4.3db and the vibrato depth is set to 14 cent
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(in reguards to OPL2 settings; to achieve this you would write 0C0h to
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OPL register 0BDh). All operator connections are fixed in FM mode. (Where
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Modulator modulates the Carrier).
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---
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00 (Modulator) - tvskmmmm
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01 (Carrier)
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t: Tremolo Enable
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v: Vibrato Enable
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s: Sustain Enable
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k: KSR
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m: Multiplier
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---
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02 - kkoooooo
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k: Key Scale Level
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o: Output Level
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---
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03 - ---qweee
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-: Not used: Write 0's
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q: Carrier Waveform
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w: Modulator Waveform
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Note: There are only two waveforms available. Sine and rectified sine (only
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the positive cycle of the sine; negative cycle "chopped off".)
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e: Feedback Control
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---
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04 (Modulator) - aaaadddd
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05 (Carrier)
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a: Attack
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d: Decay
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---
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06 (Modulator) - ssssrrrr
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07 (Carrier)
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s: Sustain
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r: Release
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Register Settings for the 15 fixed instruments.
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-----------------------------------------------
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*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*
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C C
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A These instruments are not 100% correct! There is no way to extract A
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U the register settings from the chip short of an electron microscope. U
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T I have "tuned" these instruments best I could, though I know a couple T
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I are not exactly right. Use them at your own perl! If someone wants I
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O to waste all day tuning a new set, please let me know what you get. O
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N N
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*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*CAUTION*
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Register
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--------
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00 01 02 03 04 05 06 07
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-----------------------
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0 | -- -- -- -- -- -- -- --
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1 | 05 03 10 06 74 A1 13 F4
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2 | 05 01 16 00 F9 A2 15 F5
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3 | 01 41 11 00 A0 A0 83 95
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4 | 01 41 17 00 60 F0 83 95
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5 | 24 41 1F 00 50 B0 94 94
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6 | 05 01 0B 04 65 A0 54 95
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7 | 11 41 0E 04 70 C7 13 10
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Instrument 8 | 02 44 16 06 E0 E0 31 35
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---------- 9 | 48 22 22 07 50 A1 A5 F4
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A | 05 A1 18 00 A2 A2 F5 F5
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B | 07 81 2B 05 A5 A5 03 03
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C | 01 41 08 08 A0 A0 83 95
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D | 21 61 12 00 93 92 74 75
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E | 21 62 21 00 84 85 34 15
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F | 21 62 0E 00 A1 A0 34 15
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So how accurate is this info, anyways?
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--------------------------------------
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I believe the info to be 100% accurate. The pinout was generated with the
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help of a multimeter and my Super-8 with both an NES cart and the Fami cart
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plugged in. (this allows me to measure between my known "control" board
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with the unknown "experimental" board to generate the connections).
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Register info was gleaned via writing test code and listening and capturing
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the resultant audio stream for analysis.
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---EOF---
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