YM(4)

YM(4) | Device Drivers Manual | YM(4)

# NAME

`ym` —
Yamaha OPL3-SA2 and OPL3-SA3 audio device driver

# SYNOPSIS

`ym* at acpi?`
`ym* at isapnp?`
`ym* at pnpbios? index ?`
`audio* at audiobus?`
`mpu* at ym?`
`opl* at ym?`

# DESCRIPTION

The `ym` driver provides support for Yamaha YMF711 (OPL3-SA2) and YMF715x (OPL3-SA3) sound devices.

The OPL3-SAx device has WSS compatible full-duplex 16bit CODEC, OPL3 FM synthesizer, and MPU401 compatible MIDI I/O port interface. Additionally, OPL3-SA3 has built-in ‘3D Enhanced’ equalizer.

The joystick interface is handled by the joy(4) driver.

# MIXER DEVICE

The mixer device of `ym` driver can be accessed by mixerctl(1) command. The layout is shown below.

                dac ------------------------<-----  -----------------
    midi(OPL3/ZV)->-+----------------------------+->|inputs.midi    |
    cd      ->------+-*--------------------------+->|inputs.cd      |
    line    ->----*-+-+--------------------------+->|inputs.line    |
    speaker ->----+-+-+--------------------------+->|inputs.speaker |
    mic     ->--*-+-+-+--------------------------+->|inputs.mic     |
                v v v v      monitor.monitor     |  |               |
            ---------------  -------  |  ------- |  |               |
            |record.record|->| A/D |---->| D/A |-*->|inputs.dac     |analog
            |             |  |conv.|-- ->|conv.|    |               |output
            ---------------  ------- | | -------    | outputs.master|-->
                               wave  v | wave       | equalization.*|
                             recording playback     -----------------

Note that the ‘`inputs.dac`’ is twice as sensitive as other ‘`inputs`’ volume variables.

The hardware volume changes the ‘`outputs.master`’ value.

If an external input source is unmuted by setting corresponding ‘`inputs.*.mute`’ variable to ‘`off`’, the device is never put in global power down or power save mode. This is because if the device is in global power down or power save mode, the output is automatically muted.

All the external input sources (CD playback, line input, speaker, and MIC) are muted by default.

The ‘`equalization.*`’ variables does not exists on OPL3-SA2. The ‘equalization.treble’ and ‘equalization.bass’ are enhancement only, and any values below the center position (128) don't take any effect.

# POWER MANAGEMENT

The `ym` driver is capable of power management on the OPL3-SAx devices. The following modes can be selected by setting ‘`power.save`’ variable of mixerctl(1) to ‘`powerdown`’, ‘`powersave`’, and ‘`nosave`’ respectively.

Global power-down mode
  When a subpart of the device is unused, the part is power-down after a timeout period (specified by ‘`power.save.timeout`’ variable of mixerctl(1) in seconds). When all the subparts of the device are unused, and all the external input sources are muted, the driver puts the device in ‘Global Power Down’ mode.

  On the global power down mode, the power consumption is minimized (10μA (SA3) or 200μA (SA2) typ.), but the click noise on power up/down the device is rather loud.

  This mode should not be used with headphones or hi-fi audio systems, or your ears or the systems may be damaged.
Power save mode
  When a subpart of the device is unused, the part is powered-down after a timeout period (specified by ‘`power.save.timeout`’ variable of mixerctl(1) in seconds). When all the subparts of the device are unused, and all the external input sources are muted, the driver put the device in ‘Power Save’ mode.

  In power save mode, the power consumption is reduced (5mA typ.). The click noise on power up/down of the device is very small, but this operation requires muting/unmuting the device, which make some noise. In order to reduce the noise, setting the master volume at the small value is effective.

No power-save mode
  Once the device is powered-up, it remains on after the use of the device. Once a subpart of the device is powered-up, it shall not be power-down. This mode minimizes click noises on power switching, but maximizes power consumption (30-100mA).

  On suspending, the device is put into power-save state.

# SEE ALSO

mixerctl(1), apm(4), audio(4), isapnp(4), joy(4), midi(4), mpu(4), opl(4), i386/pnpbios(4)

# HISTORY

The `ym` device driver appeared in NetBSD 1.4.

# BUGS

Although the parameters of the device are saved and restored on apm(4) suspend/resume, the DMA state is not restored. That is, if the system suspends during playback, this is not continued after suspend/resume cycle.

The joystick port is not under power management. If a joy(4) device is configured, the device will never be put in global power down or power save mode.

The external devices, such as Zoomed Video port, OPL4-ML/2, modem, and CD-ROM are not supported.

August 23, 2020 | NetBSD 10.0