Dave Lowe: Disk Number 4

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Text File | 1993-12-07 | 17.4 KB | 458 lines

------------------------------------------------------------------------------- SUPER N.E.S. MUSIC DRIVER - (c) Martin Walker 1992/1993 ------------------------------------------------------------------------------- UPDATED: 07/12/93 - Additional problem solving text 20/10/93 - TRK0call added to ReceiveStatus 21/09/93 - Info mode added for status/clock switching 14/09/93 - Interrupts disabled during Sound_Init/status bit added 26/08/93 - Mini SNES-CLR power-up routine added to Sound_Init 18/08/93 - Improved handshaking routines/ new clock routine 06/08/93 - Boot_APU anti hang-up mod added as per REV.D CAUTION #7 Updated Sound_Init/Send_Data 26/07/93 - external volume of sound calls/ problem solving section at end. 19/07/93 - to clarify initialisation procedure. SNES MUSIC DEMO --------------- To help test the music files, a file named 'SNESMUS.ROM' may be supplied. You can download this to the SNES for a demo of the music and effects. The joypad keys to use are as follows: UP/DOWN Increment/Decrement current call number. SELECT Stop all sound calls. START Start music/effect. Y Fades all sound calls. OVERVIEW -------- The player and music/effect data needs to be downloaded from its chosen ROM position to the SOUND CPU during the initialisation of the game. Suitable source code to do this appears below, along with the Sound Boot Loader routine taken from the SNES Manual (Appendix D with REV.D CAUTION #7). 1. WHEN INITIALISING THE GAME USE 'Sound_Init'. The Sound_Init routine needs to be called at power up and when 'RESET' is pressed. At both these times the SNES forces the Sound CPU to reset and then jump into its internal IPLROM routine. It is then waiting for data to be sent to it via the ports. First, a tiny routine is downloaded to clear all RAM, set up all DSP registers and initialise the Echo to minimise any stray sounds on power up. The driver is then downloaded; control then passes to the driver, and all subsequent downloads in this routine are made using the $82 DOWNLOAD command. (Sound_Init uses this technique to download the Musicdata and both sample Banks to the SOUND CPU memory). 2. TO START ANY DESIRED MUSIC OR EFFECT USE 'Send_Sound'. The following calls can be made during the game using Send_Sound. They are all made in the form: lda #N ;N = sound call number ldx #V ;V = volume (use $FF=full volume normally) jsr SendSound N = $00-$7F START Music or Effect call (See accompanying PROJECT.DOC) The 'X' register volume is only used by START calls. It may be omitted with other calls. N = $80 INIT stops all current sounds. resets master volume to maximum. (Use after fade if you require effects only). N = $81 FADE fades music and current effects to zero volume. N = $82 DOWNLOAD Stops driver processing to download music data or samples. N = $83 INFOMODE Sets mode to either status byte (default) or realtime clock. 3. FOR SUBSEQUENT LEVELS OF THE GAME USE 'Send_Data'. Send_Data stops all sound processing and then allows additional Musicdata and/or sample Banks to be downloaded. Normally both a Musicdata (.SND) file and at least 1 sample Bank (.BIN) file will need to be sent. Full details of particular files will be found in the file 'PROJECT.DOC'. ------------------------------------------------------------------------------- SOURCE CODE DETAILS ------------------------------------------------------------------------------- Since the SOUND CPU in the SNES is a completely separate processor, sending commands to it relies either on the SNES code looping until the sound code calls its 'check for external commands' routine (this can waste a lot of time that could be more usefully spent on the SNES side), or the way implemented in 'Send_Sound' below. This relies on the fact that once an external command from the SNES side has been processed by the music driver, it writes a unique number back to PORT0. By reading PORT0 from the SNES side and checking for this value the SNES programmer will only send a sound call when the sound driver has finished processing the previous one. By placing all sound calls into a buffer (16 bytes should normally be sufficient), you can call 'SendSound' at intervals without waiting each time for a response. The worst case wait will be 8mS (hardware loop time). Normally 1 sound call per VBL (20mS) should be fast enough (50 new sounds maximum per second!). KEY: < = byte (8 bit value) | = word (16 bit value) > = long word (24 bit value) >> = bank (top 8 bits of 24 bit value) ;Macro Definitions SET16 MACRO rep %00110000 ;Enable 16-bit mode ie clear M&X ENDM CLR16 MACRO sep %00110000 ;Disable 16-bit mode ie set M&X ENDM SETLONGA MACRO rep %100000 ;16 Bit Accumulator ENDM CLRLONGA MACRO sep %100000 ;8 bit Accumulator ENDM ;EQUATES APU_PORT0 equ $2140 APU_PORT1 equ $2141 APU_PORT2 equ $2142 APU_PORT3 equ $2143 SonyAddr equ $10 ;any 4 byte zero page address callnum equ $14 ;any 1 byte address SONYclock equ $15 ;word value SONYstatus equ $17 ;8 bits (1 = chan active/0 = chan stopped) SONYtrk0call equ $18 ;byte value (FF = chan stopped) SendSound: CLR16 pha ;save call number lda >APU_PORT0 ;latest value sent by SOUND CPU cmp <callnum bne SoundAbort ;previous call still not finished pla sta >APU_PORT0 ;store new call txa sta >APU_PORT1 ;store new volume inc <callnum lda <callnum sta >APU_PORT3 ;confirms a new call rts SoundAbort: pla rts ------------------------------------------------------------------------------- Sound_Init should be called as a subroutine once only during the Initialisation of the game, or after a user reset. It downloads the driver, music data and sample data to the SOUND CPU memory. ------------------------------------------------------------------------------- Sound_Init: php sei ;disable any other interrupts SET16 lda #MusicInit ;download SNES_CLR.BIN (24 bit address) sta <SonyAddr lda #RamII lda #MusicInit>>16 sta <SonyAddr+2 jsr Boot_APU ;exits straight to IPLROM SET16 lda #MusicDriver ;download driver (24 bit address) sta <SonyAddr lda #RamII lda #MusicDriver>>16 sta <SonyAddr+2 jsr SONY_send lda #$82 ;DOWNLOAD data (music) sta >APU_PORT0 SET16 lda #Musicdata sta <SonyAddr lda #Musicdata>>16 sta <SonyAddr+2 jsr SONY_send lda #$82 ;DOWNLOAD data (samples) sta >APU_PORT0 SET16 lda #Samples1 sta <SonyAddr lda #Samples1>>16 sta <SonyAddr+2 jsr SONY_send lda #$82 ;DOWNLOAD data (samples) sta >APU_PORT0 SET16 lda #Samples2 sta <SonyAddr lda #Samples2>>16 sta <SonyAddr+2 jsr SONY_send sta >APU_PORT3 plp ;restore any interrupts rts ;----------------------------------------------------------------------------- SONY_send: jsr Boot_APU CLR16 @wait0: lda >APU_PORT0 ;wait for handshake bne @wait0 dec a sta >APU_PORT2 ;acknowledge handshake sta <callnum ;init call number to $FF rts ------------------------------------------------------------------------------- Once the Sound_Init routine has been called, the following routine can be used to download additional music data (or sample data with '#Musicdata' replaced by '#Samples') which is required for later levels of the game. ------------------------------------------------------------------------------- Send_Data: CLR16 php sei ;disable any other interrupts S_D0: lda >APU_PORT0 ;latest value sent by SOUND CPU cmp <callnum bne S_D0 ;previous call still not finished lda #$82 ;DOWNLOAD data (music) sta >APU_PORT0 inc <callnum lda <callnum sta >APU_PORT3 ;forces a new call SET16 lda #Musicdata sta <SonyAddr lda #Musicdata>>16 sta <SonyAddr+2 jsr SONY_send sta >APU_PORT3 plp ;restore any interrupts rts ------------------------------------------------------------------------------- Info_Mode is used to set the mode. It only needs to be called once with the appropriate mode number in PORT1. After this the appropriate routine (either ReceiveStatus or ReceiveClock can be called at any time for the latest values. Normally, after any download the info mode defaults to 0 (status) MODE = 0 (STATUS=default) In this mode PORT1 is updated with current status of all 8 channels (bit high = channel active). This can be used to check for the end of a particular sound. PORT2 is updated with the current call in channel 0, and can be used to monitor the progress of specially written music ($FF = no call active) MODE=1 (CLOCK) In this mode PORT1 & PORT2 are updated with the current value of an internal music 'CLOCK' to allow syncing of action to music with specially designed tracks. ------------------------------------------------------------------------------- Info_Mode: CLR16 php sei ;disable any other interrupts I_M0: lda >APU_PORT0 ;latest value sent by SOUND CPU cmp <callnum bne I_M0 ;previous call still not finished lda #$83 ;INFOMODE sta >APU_PORT0 lda #0 ;0=status(default) sta >APU_PORT1 ;1=clock mode inc <callnum lda <callnum sta >APU_PORT3 ;forces a new call plp ;restore any interrupts rts ReceiveStatus: SETLONGA lda >APU_PORT1 ;16 bit (get data word) sta <SONYstatus ;8 bits of channel status CLRLONGA ;1 byte TRK0call rts ReceiveClock: SETLONGA ;clock is waiting in PORT1 & 2 lda >APU_PORT1 ;16 bit (get data word) sta <SONYclock CLRLONGA rts ------------------------------------------------------------------------------- SOUND BOOT LOADER V1.1 (from Appendix D of the SNES manual) ------------------------------------------------------------------------------- Boot_APU: php SET16 ldy #|$0000 lda #$bbaa boot_initial: cmp >APU_PORT0 bne boot_initial CLRLONGA lda #$cc bra boot_entry1 boot_repeat: lda [SonyAddr],y iny xba lda #0 bra boot_entry2 boot_loop: xba lda [SonyAddr],y iny xba boot_wait1: cmp >APU_PORT0 bne boot_wait1 inc a boot_entry2: SETLONGA sta >APU_PORT0 CLRLONGA dex bne boot_loop boot_wait2: cmp >APU_PORT0 bne boot_wait2 boot_zero: adc #3 beq boot_zero boot_entry1: pha SETLONGA lda [SonyAddr],y iny iny tax lda [SonyAddr],y iny iny sta >APU_PORT2 CLRLONGA cpx #|1 lda #0 rol a sta >APU_PORT1 adc #$7f pla sta >APU_PORT0 boot_wait3: cmp >APU_PORT0 bne boot_wait3 bvs boot_repeat boot_ret: plp rts ------------------------------------------------------------------------------ SNES MUSIC PROBLEM SOLVING ------------------------------------------------------------------------------ PROBLEM 1: Music crashes after using the 'reset' button REASON: At this time the SNES hardware forces the Sound CPU to reset and then jump into its internal IPLROM routine. It is then waiting for data to be sent to it via the ports, using the Boot_APU routine (above) which is reprinted from the SNES manual. Although on 'RESET' the sound driver and data are still in sound memory, you MUST treat this button the same as a power up and use 'Sound_Init' CURE: ALWAYS use 'Sound_Init' after a 'RESET', rather then Send_Data. PROBLEM 2: Corruption of sample data after loading new BANK1. REASON: If after loading a new bank of sounds you get some noises garbled, it is possible that the musician has inadvertantly allowed BANK2 to overwrite the end of BANK1 data by a few bytes. Normally a BANK1 load followed by BANK2 will ensure that the sample pointer table at the beginning of each bank is preserved, and a tiny corruption at the end of the final sample in BANK1 may be inaudible, but loading a new BANK1 may overwrite the table at the beginning of BANK2. This will cause every sound in BANK2 to emerge as gibberish. You can check for this by re-sending the banks in the opposite order. If the problem disappears, contact the musician for a BANK update file! CURE: Send BANKS in the order BANK1 then BANK2 for a temporary cure, and contact the musician for an amended BANK file. PROBLEM 3: Occasional hang-up after sending new sound data. REASON: Bug in Nintendo's own Boot_APU routine (see REV.D CAUTION #7). It is possible that an interrupt will strike during a download of sound data - if this happens during the 300-400 microseconds of handshake it is possible that the SNES side will miss the ackowledgement and then wait for indefinitely (crash). CURE: Make sure you disable SNES interrupts during Sound_Init as shown. PROBLEM 4: Sound always hangs when game is aborted. REASON: Only on power up or by pressing RESET will the Sound CPU be in a state to use Sound_Init. Restarting the game as a user option will not work in this case. CURE: Re-arrange the code so that Sound_Init occurs before the game restart point, and use Send_Data to re-send the first music data required. PROBLEM 5: Occasional crackle or 'break-up' in sound with lots of simultaneous sounds. REASON: It is possible to overload the sound chip, but sometimes this only appears during playtesting when everyting is happening at once. CURE: First confirm that it is overload by inserting a temporary '/2' command before the volume setting in SendSound to drastically reduce all volumes. If this cures the problem then remove the '/2' command and set all volumes to a significantly lower setting (e.g. from $FF to $D0) and retest.