| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| IRQ | T1 | T2 | Not used | ||||
- bit 7: IRQ Flag.
- Set whenever any timer has elapsed.
- bit 6: Timer 1 Flag.
- Set every time the preset time in Timer 1 has elapsed.
- bit 5: Timer 2 Flag.
- Set every time the preset time in Timer 2 has elapsed.
Timer interrupts are not wired to any IRQ (why??). The timers can be used to detect the OPL2/OPL3 chip (see Appendix B).
01: Test Register / Waveform Select Enable:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| WSE | Test Register | ||||||
- bit 5: Waveform Select Enable.
- If clear, all channels will use normal sine wave. If set, register E0-F5 (Waveform Select) contents will be used.
- bits 0-4: Test Register.
- Must be reset to zero before any operation.
02: Timer 1 Count:
Upward 8 bit counter with a resolution of 80 æsec. If an overflow occurs, the status register bit is set, and the preset value is loaded into the timer again.
03: Timer 2 Count:
Same as Timer 1, but with a resolution of 320 æsec.
004 (port: base+1): IRQ-Reset / Mask / Start:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Rst | T1M | T2M | T2S | T1S |
- bit 7: IRQ-Reset.
- Resets timer and IRQ flags in status register. All other bits are ignored when this bit is set.
- bit 6: Timer 1 Mask.
- If 1, status register is not affected in overflow.
- bit 5: Timer 2 Mask.
- Same as above.
- bit 1: Timer 2 Start.
- Timer on/off.
- bit 0: Timer 1 Start.
- Same as above.
104 (port: base+3): Four-Operator Enable:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| ChB | ChA | Ch9 | Ch2 | Ch1 | Ch0 |
- bit 5: Enable four-operator synthesis for channel pair 11 - 14 (decimal).
- bit 4: Same as above for channel pair 10 - 13.
- bit 3: Same as above for channel pair 9 - 12.
- bit 2: Same as above for channel pair 2 - 5.
- bit 1: Same as above for channel pair 1 - 4.
- bit 0: Same as above for channel pair 0 - 3.
- bit 4: Same as above for channel pair 10 - 13.
If reset to zero, OPL3 can produce 18 two-operator sounds at a time.
If nonzero, OPL3 produces four-operator sound in appropriate channel pair.
105 (port: base+3): OPL3 Mode Enable:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| OPL |
- bit 0:
- OPL3 Mode Enable. When set, OPL3 extensions (36 operators, 4-OP synthesis, 8 waveforms, stereo output) can be used. When reset, the chip behaves as an ordinary OPL2. This bit is zero by default for compatibility with OPL2.
08: CSW / NOTE-SEL:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| CSW | N-S |
- bit 7:
- Composite sine wave mode on/off. All KEY-ON bits must be clear in order to use this mode. The card is unable to create any other sound when in CSW mode. (Unfortunately, I have no info how to use this mode :-< ).
- bit 6:
- NOTE-SEL. Controls the split point of the keyboard. When 0, the keyboard split is the second bit from the bit 8 of the F-Number. When 1, the MSb of the F-Number is used. (???)
20-35: Tremolo / Vibrato / Sustain / KSR / Frequency Multiplication Factor:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Tre | Vib | Sus | KSR | Multiplication | |||
- bit 7:
- Tremolo (Amplitude vibrato) on/off.
- bit 6:
- Frequency vibrato on/off.
- bit 5:
- Sound Sustaining. When 1, operator's output level will be held at its sustain level until a KEY-OFF is done.
- bit 4:
- Envelope scaling (KSR) on/off. When 1, higher notes are shorter than lower notes.
- bits 0-3:
- Frequency Multiplication Factor (MULTI). Operator's frequency
is set to (see registers A0, B0) F-Number * Factor.
MULTI Factor 0 1/2 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 10 12 12 13 12 14 15 15 15
40-55: Key Scale Level / Output Level:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| KSL | Output Level | ||||||
- bits 6-7: Key Scale Level.
- Attenuates output level towards higher pitch:
KSL Attenuation 0 - 1 1.5 dB/oct 2 3.0 dB/oct 3 6.0 dB/oct - bits 0-5: Output Level.
- Attenuates the operator output level. 0 is the
loudest, 3F is the softest. In additive synthesis, varying
the output level of any operator varies the volume of its
corresponding channel. In FM synthesis, varying the output level
of the carrier varies the volume of the channel. Varying the
output of the modulator will change the frequency spectrum
produced by the carrier.
The following table summarizes which operators' output levels should be updated when trying to change channel output level.
Mode Op 1 Op 2 Op 3 Op 4 AM + + N/A N/A FM - + N/A N/A FM-FM - - - + AM-FM + - - + FM-AM - + - + AM-AM + - + +
60-75: Attack Rate / Decay Rate:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Attack Rate | Decay Rate | ||||||
- bits 4-7: Attack Rate.
- Determines the rising time for the sound. The higher the value, the faster the attack.
- bits 0-3: Decay Rate.
- Determines the diminishing time for the sound. The higher the value, the shorter the decay.
80-95: Sustain Level / Release Rate:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Sustain Level | Release Rate | ||||||
- bits 4-7: Sustain Level.
- Determines the point at which the sound ceases to decay and chages to a sound having a constant level. The sustain level is expressed as a fraction of the maximum level. 0 is the softest and F is the loudest sustain level. Note that the Sustain-bit in the register 20-35 must be set for this to have an effect.
- bits 0-3: Release Rate.
- Determines the rate at which the sound disappears after KEY-OFF. The higher the value, the shorter the release.
A0-A8: Frequency Number:
Determines the pitch of the note. Highest bits of F-Number are stored in the register below.B0-B8: Key On / Block Number / F-Number(hi bits):
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| KEY | Block Num. | Freq | |||||
- bit 5: KEY-ON.
- When 1, channel output is enabled.
- bits 2-4: Block Number.
- Roughly determines the octave.
- bits 0-1: Frequency Number.
- 2 highest bits of the above register.
- The following formula is used to determine F-Number and Block:
- F-Number = Music Frequency * 2^(20-Block) / 49716 Hz
- The following formula is used to determine F-Number and Block:
- NOTE:
- In four-operator mode only the register value of Operators 1 and 2 is used, value of Operators 3 and 4 in this register is ignored. In other words: one channel uses only one frequency, block and KEY-ON value at a time, regardless whether it is a two- or four-operator channel.
BD: Tremolo Depth / Vibrato Depth / Percussion Mode / BD/SD/TT/CY/HH On:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Tre | Vib | Per | BD | SD | TT | CY | HH |
- bit 7: Tremolo (Amplitude Vibrato) Depth.
- 0 = 1.0dB, 1 = 4.8dB.
- bit 6: Frequency Vibrato Depth.
- 0 = 7 cents, 1 = 14 cents. A "cent" is 1/100 of a semi-tone.
- bit 5: Percussion Mode.
- 0 = Melodic Mode, 1 = Percussion Mode.
- bit 4: BD On.
- KEY-ON of the Bass Drum channel.
- bit 3: SD On.
- KEY-ON of the Snare Drum channel.
- bit 2: TT On.
- KEY-ON of the Tom-Tom channel.
- bit 1: CY On.
- KEY-ON of the Cymbal channel.
- bit 0: HH On.
- KEY-ON of the Hi-Hat channel.
- NOTE:
- KEY-ON bits of channels 6, 7 and 8 must be clear and their F-Nums, Attack/Decay/Release rates, etc. must be set properly to use percussion mode.
C0-C8: FeedBack Modulation Factor / Synthesis Type:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| R | L | FeedBack | Syn | ||||
- bit 5: Right Speaker Enable.
- When set, channel output goes to right speaker.
- bit 4: Left Speaker Enable.
- When set, channel output goes to left
speaker. At least one of these bits must be set to hear
the channel.
These two bits can be used to realize sound "panning", but this method offers only three pan positions (left/center/right). These bits apply only to operators producing sound (Carriers). Modulators are not affected by their setting. - bits 1-3: FeedBack Modulation Factor.
- If 0, no feedback is present. If 1-7,
operator 1 will send a portion of its output back into itself.
When in four-operator mode, the FeedBack value is used only by Operator 1, value of Operators 2, 3 and 4 is ignored.FeedBack Factor 0 0 1 y/16 2 y/8 3 y/4 4 y/2 5 y 6 2y 7 4y - bit 0: Synthesis Type.
- 1 = Additive synthesis, 0 = Frequency Modulation
In four-operator mode, there are two bits controlling the
synthesis type. Both are the bit 0 of register C0, one of
Operators 1 and 2 and the second of Operators 3 and 4.
Op 1&2 Op 3&4 Type 0 NONE FM 1 NONE AM 0 0 FM-FM 1 0 AM-FM 0 1 FM-AM 1 1 AM-AM
E0-F5: Waveform Select:
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| WaveForm | |||||||
- bits 0-2: WaveForm Select (WS):
-
WaveForm 0: Sine
WaveForm 1: Half-Sine
WaveForm 2: Abs-Sine
WaveForm 3: Pulse-Sine
WaveForm 4: Sine - even periods only
WaveForm 5: Abs-Sine - even periods only
WaveForm 6: Square
WaveForm 7: Derived Square
- NOTE:
- Bit 5 of register 01 must be set to use waveforms other than sine. Waveforms 4-7 are available only on OPL3. See files WAVEn.GIF for real waveforms, where n is a number between 0 and 7.
APPENDIX A - EXAMPLES
These examples show a few working routines used in my MUS Player. They are written in Borland C++ 3.1 but should be easy to translate to any other language.--------------------------------- cut here ---------------------------------
// I prefer using these Assembler-like types
typedef unsigned int WORD;
typedef unsigned char BYTE;
/*
* FM Synthesizer base port. SB Pro II - 0x220, Adlib 0x388
*/
WORD FMport = 0x220;
/*
* Enables OPL3 extensions.
*/
WORD OPL3 = 1;
/*
* Direct write to any Adlib/SB Pro II FM synthetiser register.
* reg - register number (range 0x001-0x0F5 and 0x101-0x1F5). When high byte
* of reg is zero, data go to port FMport, otherwise to FMport+2
* data - register value to be written
*/
BYTE FMwriteReg(WORD reg, BYTE data)
{
asm {
mov dx,FMport
mov ax,reg
or ah,ah // high byte is nonzero -- write to port base+2
jz out1
inc dx
inc dx
}
out1: asm {
out dx,al
mov cx,6
}
loop1:asm { // delay between writes
in al,dx
loop loop1
inc dx
mov al,data
out dx,al
dec dx
mov cx,36
}
loop2:asm { // delay after data write
in al,dx
loop loop2
}
return _AL;
}
/*
* Write to an operator pair. To be used for register bases of 0x20, 0x40,
* 0x60, 0x80 and 0xE0.
*/
void FMwriteChannel(BYTE regbase, BYTE channel, BYTE data1, BYTE data2)
{
static BYTE adlib_op[] = {0, 1, 2, 8, 9, 10, 16, 17, 18};
static BYTE sbpro_op[] = { 0, 1, 2, 6, 7, 8, 12, 13, 14,
18, 19, 20, 24, 25, 26, 30, 31, 32};
static WORD rg[] = {0x000,0x001,0x002,0x003,0x004,0x005,
0x008,0x009,0x00A,0x00B,0x00C,0x00D,
0x010,0x011,0x012,0x013,0x014,0x015,
0x100,0x101,0x102,0x103,0x104,0x105,
0x108,0x109,0x10A,0x10B,0x10C,0x10D,
0x110,0x111,0x112,0x113,0x114,0x115};
if (OPL3)
{
register WORD reg = sbpro_op[channel];
FMwriteReg(rg[reg]+regbase, data1);
FMwriteReg(rg[reg+3]+regbase, data2);
} else {
register WORD reg = regbase+adlib_op[channel];
FMwriteReg(reg, data1);
FMwriteReg(reg+3, data2);
}
}
/*
* Write to channel a single value. To be used for register bases of
* 0xA0, 0xB0 and 0xC0.
*/
void FMwriteValue(BYTE regbase, BYTE channel, BYTE value)
{
static WORD ch[] = {0x000,0x001,0x002,0x003,0x004,0x005,0x006,0x007,0x008,
0x100,0x101,0x102,0x103,0x104,0x105,0x106,0x107,0x108};
register WORD chan;
if (OPL3)
chan = ch[channel];
else
chan = channel;
FMwriteReg(regbase + chan, value);
}
--------------------------------- cut here ---------------------------------
APPENDIX B - DETECTION METHODS
An official method of Adlib (OPL2) detection is:- Reset Timer 1 and Timer 2: write 60h to register 4.
- Reset the IRQ: write 80h to register 4. NOTE: Steps 1 and 2 can't be combined together.
- Read status register: read port base+0 (388h). Save the result.
- Set Timer 1 to FFh: write FFh to register 2.
- Unmask and start Timer 1: write 21h to register 4.
- Wait in a delay loop for at least 80 æsec.
- Read status register: read port base+0 (388h). Save the result.
- Reset Timer 1, Timer 2 and IRQ as in steps 1 and 2.
- Test the results of the two reads: the first should be 0,
the second should be C0h.
If either is incorrect, then the OPL2 is not present.
- NOTE1:
- You should AND the result bytes with E0h because the unused bits are undefined.
- NOTE2:
- This testing method doesn't work in some SoundBlaster compatible cards.
OPL3 DETECTION
- Detect OPL2. If present, continue.
- Read status register: read port base+0.
- AND the result with 06h.
- If the result is zero, you have OPL3, otherwise OPL2.
- NOTE:
- This is NOT an official method. I have dug it out of a sound driver. I haven't tested it, because I haven't an OPL2 card (Adlib, SB Pro I). Nevertheless it "detects" my SB Pro II properly. ;-)
Another possible detection method for distinguishing between SB Pro I and SB Pro II would be to try to detect OPL2 at I/O port base+0 and then at port base+2. The first test should succeed and the second should fail if OPL3 is present. (Remember: SB Pro I contains twin OPL2 chips at addresses base+0 and base+2, while SB Pro II contains one OPL3 chip at I/O address base+0 thru base+3).
BLASTER ENVIRONMENT VARIABLE
Perhaps the most recommended "detection" method. Reading this variable avoids blindfold I/O port scanning and possible device conflicts. The user is responsible for its proper setting.The variable has this format:
BLASTER=Aaddr Iirq Ddma Ttype
- A: Base I/O address given in hex. For most Sound Blasters the default is 220.
- I: IRQ Number (decimal). Default 7.
- D: DMA Number (decimal). Default 1.
- T: Card Type (decimal):
- I: IRQ Number (decimal). Default 7.
- 1 - Sound Blaster 1.5
2 - Sound Blaster Pro I
3 - Sound Blaster 2.0
4 - Sound Blaster Pro II
Example: BLASTER=A220 I7 D1 T4
REFERENCES
- Title: The PC Games Programmers Encyclopedia
Authors: Mark Feldman and many others on Usenet and Internet
FTP: teeri.oulu.fi
/pub/msdos/programming/gpe
... you can find (almost) everything you need there - Title: Sound Blaster - The Official Book
Authors: Richard Heimlich, David M. Golden, Ivan Luk, Peter M. Ridge
Publishers: Osborne/McGraw Hill
ISBN: 0-07-881907-5
... this is a number-one in my book-wishlist. If anyone wanted to get rid of the book, I wouldn't scorn it ... :-) - Title: The SoundBlaster Developer Kit
Publishers: Creative Labs Inc
Creative Technology PTE LTD
... I wonder if you can find something comprehensible in that.