ReSonique II Sound Card Manual

ReSonique II is the audio hardware of the Izarra3000. It is a combination card with a Sound Blaster 16 compatible digital audio path and an OPL3 FM synthesizer. This manual describes what a DOS program finds when it examines the card.

The parts of the card

Section	Compatibility	Base port	IRQ	DMA
Digital audio	Sound Blaster 16 / CT1745 mixer	`0x220`	7	8-bit: 1, 16-bit: 5
FM synthesis	OPL3 (Yamaha YMF262)	`0x388`	n/a	n/a
Codec	Windows Sound System (AD1848)	`0x530`	11	0
Wavetable daughterboard header	MPU-401	`0x300`	9	n/a
Rear MIDI/game port	MPU-401	`0x330`	9	n/a

These are the power-on defaults. Toka-DOS puts the same values in BLASTER. The base ports are fixed. The IRQ and the DMA are not fixed. See How to change the card resources for the tool that changes them.

The digital section and the FM section use the standard Sound Blaster and AdLib addresses, which are fixed. ReSonique II gives a different fixed port to the internal wavetable header and to the rear MIDI connection. Thus software can select one path or the other directly. The rear 15-pin connector also carries the usual joystick signals.

Why the Sound Blaster uses IRQ 7

IRQ 5 is the factory setting of the Sound Blaster 16, thus you can expect IRQ 5 here. But ReSonique II uses IRQ 7, because DOS software is in two groups, and only IRQ 7 is correct for both groups:

A program that reads BLASTER operates on any line, because the variable always gives the current configuration.
A program with a fixed IRQ in its code almost always uses 7. IRQ 7 was the factory setting of the Sound Blaster 1.x and the Sound Blaster 2.0, and the drivers were written for those cards. On IRQ 5, such a program receives no interrupt. With most drivers, the playback starts and then stops after the first DMA block. The result is a short click, and no more sound.

A fixed IRQ 5 is not frequent. IRQ 5 became a default only with the SB16-class cards, and at that time a program usually read BLASTER. If a game needs IRQ 5, run SNDCTRL before you start the game.

The AD1848 codec cannot share a line with the Sound Blaster. Thus it uses IRQ 11, and not the WSS standard IRQ 7. A real combination card separates the two lines with jumpers in the same way.

The BLASTER variable

Toka-DOS sets this variable in AUTOEXEC.BAT. Thus a Sound Blaster program finds the card without a probe:

SET BLASTER=A220 I7 D1 H5 P300 T6

The values are base address 0x220, IRQ 7, 8-bit DMA channel 1, 16-bit DMA channel 5, wavetable MPU port 0x300, and card type 6 (Sound Blaster 16). They agree with the defaults above.

Toka-DOS makes this line from the configuration of the machine. Thus the line follows the values that you set. Toka-DOS does not change an AUTOEXEC.BAT that you edited. In an edited file, SNDCTRL writes the SET BLASTER line again in position, and does not change the remainder of the file.

How to change the card resources

The SNDCTRL utility sets the hardware parameters of the ReSonique II sound card. It is the setup utility of the card, and it is in C:\DOS on each Toka-DOS disk. Run it from the DOS prompt:

C:\> SNDCTRL

The SNDCTRL configuration screen

The arrow keys and Tab move between the values. Press Enter on a value to select from the list that the hardware supports. Press F10 to apply the changes. Esc keeps the previous values. A value that does not apply to a device shows as *.

The lists show only the available values. A line or a channel that the other device holds is not in the list. Thus you cannot give the same resource to the Sound Blaster and to the codec. The emulator obeys the same rule at startup.

The apply operation does four things:

The hardware changes immediately, and a restart is not necessary. SNDCTRL writes the Interrupt and DMA Setup registers of the mixer for the Sound Blaster, and the config register for the codec.
SNDCTRL saves the values in CMOS. Thus the machine uses them again at the next boot.
SNDCTRL changes BLASTER in the current environment. Thus a game that you start from the same prompt uses the new values.
SNDCTRL writes the SET BLASTER line in C:\AUTOEXEC.BAT again. Thus the next boot uses the same values.

SNDCTRL changes an existing variable. It does not make a new one. If you removed the BLASTER line, SNDCTRL reports this and does not put the line back.

From the command line

You can give each setting as a switch. SNDCTRL then applies the setting and exits, and it draws nothing. This form is useful in a batch file:

SNDCTRL /SBIRQ:5              Sound Blaster IRQ        2, 5, 7, 10
SNDCTRL /SBDMAL:1             Sound Blaster 8-bit DMA  0, 1, 3
SNDCTRL /SBDMAH:5             Sound Blaster 16-bit DMA 5, 6, 7
SNDCTRL /WSSIRQ:11            Codec IRQ                7, 9, 10, 11
SNDCTRL /WSSDMA:0             Codec DMA                0, 1, 3
SNDCTRL /MPU:330              MPU-401 port             300, 330
SNDCTRL /S                    show the current assignment, change nothing
SNDCTRL /?                    usage

You can use more than one switch: SNDCTRL /SBIRQ:5 /MPU:330. If the hardware cannot use a value, SNDCTRL refuses it and lists the values that the hardware can use. If a combination would put both devices on one line or on one channel, SNDCTRL refuses the combination and writes nothing.

SNDCTRL /S reads the Sound Blaster mixer. Thus it gives the current values of that device, even after a different program changed them.

The codec cannot be read this way. A Windows Sound System board answers its configuration register with an identification value, not with the line and the channel that were written into it, so no program can ask the card what routing it has. For the codec, SNDCTRL reports the saved assignment, the same way it reports the MPU-401 port. A game that moves the codec for its own run does not appear here.

Why the machine config file has nothing to set

The file had these keys before. [audio.sound_blaster] irq and the related keys are now removed. The machine boots from CMOS. Thus, after SNDCTRL saved an assignment, a change to those keys had no effect on the machine.

An old config file continues to load. IzarraVM ignores the removed keys, and writes their names in the log.

The file keeps the settings that CMOS does not hold. These are enabled, which says if the device is fitted, and base, which is the I/O base of the codec. The base is fixed wiring on the board, and not a selectable resource.

--sb-irq, --sb-dma, and --sb-high-dma continue to operate on the command line. They set the power-on values for a machine with no saved CMOS. Each headless run is such a machine, because a headless run does not load CMOS. On a configured machine, the saved assignment has priority, and the emulator reports this:

WARN the saved CMOS overrode these flags; it is what the machine boots from.
Change the CPU speed with GSWMODE or the BIOS setup panel (Del), and the sound
card with SNDCTRL, both inside DOS -- or delete cmos.bin to start from the
flags again  flags=--sb-irq 5

--cpu behaves in the same way, for the same reason.

How to set the volume

Use the SNDMIXER utility to set the volume levels of the card. It shows seven vertical faders for the mixer of the card: MASTER, FMSYNTH, WAVE, CD-ROM, MIDI, the PC speaker, and AMP. SNDMIXER applies each level as you move the fader. It saves the levels to a file, and AUTOEXEC.BAT sets them again at the next boot.

C:\> SNDMIXER

Tab and the arrow keys move between the faders. After the faders, they move to the Accept button and the Cancel button at the bottom of the box. Enter or Space operates the selected button. Accept exits and keeps the new levels. Cancel sets the levels that were in effect when the mixer opened. F10 saves the levels for the next boot.

There is no line-in fader and no microphone fader. The machine emulates playback only. Thus those inputs have no signal, and a control has nothing to change.

Each leg of the card starts at 0 dB, and the mix keeps its headroom after the mixer. Thus nothing clips at the default settings, and the faders cover the full range below the default. Each step is 4 dB. This puts the ten positions at equal distances, and not in the top part of a 62 dB scale. The full switch list is in SNDMIXER.

Two of the seven faders are not standard Sound Blaster registers:

PC speaker is the PC-SPK input of the card (mixer register 0x3B). On the real chip, that input is two bits wide. Thus the fader has four positions, and not ten. The card mixes the beeper, and MASTER thus changes its level also.
MIDI is the wavetable synthesizer. A real SB16 has no register for a wavetable. Its "MIDI" volume is the FM bus, which is the FMSYNTH fader on this card. Thus the ReSonique II adds two registers of its own, at 0x50 and 0x51. They are in the same register file, and on the same 5-bit scale as the others.

Only this pair has a mute bit, in D0. On this pair, a level of zero is the quietest audible step, and not silence. The wavetable is the only source with no second control in the machine. Without this behavior, a program that cleared the mixer registers would make the wavetable silent, with no cause on the screen. Use the mute bit to mute the wavetable.

Output gain (AMP)

The seventh fader is not a volume control. It is the output amplifier of the card. It is the only control on the card that adds level.

The amplifier is on the internal bus of the card, beside the master. It increases the level of the FM synthesis, of the digital audio from the Sound Blaster DSP, and of the PC-speaker input. The CD audio and the Windows Sound System codec do not go through it. Those two legs reach the summing node with their own attenuation only. Thus the AMP fader does not increase the level of a Red Book track or of a WSS recording.

Register	Bits	Field	Positions
`0x41`	D7-D6	Output gain, left	0, 1, 2, 3
`0x42`	D7-D6	Output gain, right	0, 1, 2, 3

Each position is 6 dB:

Position	Gain	Fader step
0	0 dB	0
1	+6 dB	3
2	+12 dB	7
3	+18 dB	10

Position 0 is the power-on setting. It is the bottom of the fader travel, and it is not a mute. An amplifier at 0 dB sends its input through with no change, and each position above 0 adds gain. SNDMIXER writes the two registers together, from one fader. A difference between them is a change of balance, and not a change of level.

Warning: the gain can clip the signal. The mix keeps 6 dB of headroom at the point where the card sums its legs. That is sufficient for one leg at full scale. The amplifier operates on its three legs before that sum. Thus position 1 uses the full reserve. Positions 2 and 3 are more than the reserve, and a loud source will distort. Two examples of a loud source are a DSP voice at full scale, and the FM and the voice together.

The card gives these positions, and the fader gives them. Neither one refuses the setting, and neither one decreases the level automatically. Use the positions to make a quiet game louder, and not to make a loud game louder.

Digital audio (Sound Blaster 16 compatible)

The CT1745-compatible mixer and the DSP answer at 0x220 to 0x22F. They use the power-on IRQ and DMA in the table above. You can move both from inside DOS with SNDCTRL, for a program that needs different values. The BLASTER line of Toka-DOS always agrees with the current configuration.

The guest can write the Interrupt and DMA Setup registers of the mixer (0x80 and 0x81). Thus a program that configures the card in that way also moves it. It uses the same path as SNDCTRL.

FM synthesis (OPL3)

The FM synthesizer is at 0x388, the standard AdLib, OPL2, and OPL3 address. It answers as a real OPL3 (Yamaha YMF262). It has the full four-operator instrument set, and the two-operator patches of the OPL2. Software detects it as it detects real OPL3 hardware: it reads back the status register and the timer registers. This is the classic AdLib detection routine.

Creative ADPCM

The DSP decodes Creative ADPCM as a real SB16 does. The decoder is part of the digital audio path, and not a separate device. The playback commands are the 4-bit, 2.6-bit, and 2-bit commands: 0x74 to 0x77, 0x16, 0x17, and their auto-init forms. They expand the compressed DMA stream to 8-bit samples, through the adaptive predictor of the DSP. The DSP raises one interrupt at each programmed block boundary, as it does in raw PCM playback. A program that sends the ADPCM DSP commands needs no other detection and no other configuration.

MIDI and wavetable

The card has two MPU-401 port pairs. A game that is configured for a wavetable daughterboard sends its music to 0x300. Toka-DOS gives this port as P300 in BLASTER. This path goes to the daughterboard pin headers in the case. A game that is configured for an external MPU-401 sends its music to 0x330, which goes to the rear MIDI/game connector. A breakout cable gives the standard MIDI sockets.

Both ports supply UART output and the playback part of the MPU-401 intelligent mode. Software in intelligent mode can use eight timed tracks, the conductor, changes of tempo and timebase, and the start and the stop of playback. The two ports share IRQ 9 for the acknowledgements and the data requests. Neither interface supplies recording, external clock sync, metronome input, or MPU reference filters.

IzarraVM supplies the daughterboard and the external receiver separately. The GUI guide describes those host settings and their status messages. The recipes give the procedures that use them.