API Reference Register getters and setters - DhrBaksteen/ArduinoOPL2 GitHub Wiki

byte OPL2::getAttack(byte channel, byte operatorNum);

Get the attck rate of the given channel and operator. The higher the value the faster the attack.

• When set to 0 the sound will never attack
• When set to 15 the sound will immediately be at maximum level

void OPL2::setAttack(byte channel, byte operatorNum, byte attack);

Set the attack rate of a channel operator. This defines the time it takes for the operator's output level to rise from 0 to maximum. The attack portion of the envelope is triggered when keyOn of a channel is set to true. The higher the value the faster the attack.

• When set to 0 the sound will never attack
• When set to 15 the sound will immediately be at maximum level

byte OPL2::getBlock(byte channel);

Get the current frequency block for the given channel. The frequency block determines the frequency range of the F-numbers. This is sometimes interpreted as the current octave.

void OPL2::byte setBlock(byte channel, byte block);

Set the frequency block for the given channel. The frequency block determines the frequency range of the F-numbers. The interval between two F-numbers is the same as the frequency of F-num = 1 in the table below.

byte OPL2::getDecay(byte channel, byte operatorNum);

Get the decay rate of the given channel and operator. The higher the value the quicker the decay to sustain level will be.

• When set to 0 the sound will never decay to sustain level, but remain at maximum output level

void OPL2::setDecay(byte channel, byte operatorNum, byte decay);

Set the decay rate of the channel operator. This defines the time it takes for the operator's output level to drop from maximum to sustain level. The decay portion of the envelope is triggered immediately after attack. The higher the value the quicker the decay to sustain level will be.

• When set to 0 the sound will never decay to sustain level, but remain at maximum output level

bool OPL2::getDeepTremolo();

Returns whether deep tremolo is enabled. This is a chip-wide setting that applies to all operators.

• When disabled (default) tremolo depth is 1.0 dB
• when deep tremolo is enabled all tremolos have a depth of 4.8 dB

void OPL2::byte setDeepTremolo(bool enable);

This setting enables deeper tremolos. Normally tremolos will make the channel's output level vibrate with a 1.0dB depth, but when this setting is enabled tremolos wil have a 4.8dB depth. This is a chip-wide setting, meaning that it will affect all channels. By default this setting is disabled.

bool OPL2::getDeepVibrato();

Returns whether deep vibrato is enabled. This is a chip-wide setting that applies to all operators.

• When disabled (default) vibrato will be 7/100 semi-tones
• When enabled it will be doubled to 14/100 semi-tones

void OPL2::byte setDeepVibrato(bool enable);

This setting enables deeper vibratos. By default this setting is disabled.

• When disabled (default) vibrato will be 7/100 semi-tones
• When enabled it will be doubled to 14/100 semi-tones

byte OPL2::getDrums();

Returns a value where each bit indicates what drum sound is currently active. In order to play drum sounds the OPL2 must be set into percussive mode first using setPercussive.

void OPL2::byte setDrums(bool bass, bool snare, bool tom, bool cymbal, bool hihat);

Plays various drum sounds. In order to play a drumsound the OPL2 must be placed in percussive mode using setPercussion(true). This function works the same as setKeyOn. To play a drum sound the respective parameter must be set to true and disabled first by setting it to false before the same drum sound can be triggered again.

bool OPL2::getEnvelopeScaling(byte channel, byte operatorNum);

Returns wheter envelope scaling (KSR) is enabled. When enabled the duration of the envelope will be shorter as the frequency of the operator increases. By default envelope scaling will be disabled.

void OPL2::setEnvelopeScaling(byte channel, byte operatorNum, bool enable);

When enabled scale the duration of the envelope as the frequency rises. By default envelope scaling is disabled.

byte OPL2::getFeedback(byte channel);

Get the feedback modulation factor for the given channel. When set to a value greater than 0 then operator 1 will send part of its otput back into itself.

void OPL2::byte setFeedback(byte channel, byte feedback);

Set the feedback modulation factor of the given channel. This causes operator 1 to send a portion of its output back into itself when enabled. By default operator feedback is disabled.

short OPL2::getFNumber(byte channel);

Get the frequency number for the given channel. The actual frequency of the channel depends on the frequency block set using the setBlock function. When the F-number of a channel is set to 0 then its output frequency will always be 0 Hz, regardless of the block.

void OPL2::setFNumber(byte channel, short fNumber);

Sets the frequency number for the given channel. The actual frequency of the channel depends on the frequency block set using the setBlock function. When the F-number of a channel is set to 0 then its output frequency will always be 0 Hz, regardless of the block.

bool OPL2::getKeyOn(byte channel);

Returns whether the channel is currently generating a sound.

void OPL2::setKeyOn(byte channel, bool keyOn);

Enable or disable audio output on a given channel. When a channel is enabled the attack portion of the channel envelope is triggered and the channel starts to output a tone at the set frequency that rises in volume according to the set attack rate. When disabled the release portion of the envelope is triggered that makes the note fade out at the set release rate until the channel is silent.

• Note that when percussion mode is enabled keyOn of channels 6, 7 and 8 must remain false as drum sounds are triggered differently.

bool OPL2::getMaintainSustain(byte channel, byte operatorNum);

Returns whether sustain is enabled on the given channel and operator.

• If sustain is enabled then setSustain can be used to define a sustain level of an operator. The operator will remain at sustain level until the key is set to off with setKeyOn (false)
• If disabled (default) then the operator will immediately jump to the release portion of its envelope after the decay period

void OPL2::setMaintainSustain(byte channel, byte operatorNum, bool enable);

Alters whether the operator's envelope should maintain sustain level. When enabled the operator will hold the output at sustain level until the release phase of the envelope is triggered by disabling output with setKeyOn(false). If disabled the release phase of the envelope will trigger immediately after the decay phase. Note that setKeyOn must still be disabled before triggering the next note in this case. By default sustain will be disabled.

byte OPL2::getMultiplier(byte channel, byte operatorNum);

Get the frequency multiplication factor of the given channel and operator. The multiplication factor will be equal to the value set, except when set to 0 (default) when then multiplication factor will be 0.5. The F-number is multiplied by this multiplication factor to get the eventual frequency number.

void OPL2::setMultiplier(byte channel, byte operatorNum, byte multiplier);

Set the frequency multiplication factor for the given operator.

bool OPL2::getPercussion();

Returns whether percussion mode is currently enabled or not. When enabled setDrums can be used to play various drum sounds, but the number of available channels will drop from 9 to 6 as the OPL2 requires 6 operators to produce the drum sounds. By default percussion mode is disabled.

void OPL2::byte setPercussion(bool enable);

Set whether percussion mode is enabled or not. When enabled setDrums can be used to play various drum sounds, but the number of available channels will drop from 9 to 6 as the OPL2 requires 6 operators to produce the drum sounds. By default percussion mode is disabled.

byte OPL2::getRelease(byte channel, byte operatorNum);

Get the release rate of the given channel and operator. The higher the value the quicker the release.

void OPL2::setRelease(byte channel, byte operatorNum, byte release);

Set the release rate of the given channel and operator. The higher the value the quicker the release.

byte OPL2::getScalingLevel(byte channel, byte operatorNum);

Get the key scale level of the given channel and operator. This determines the attenuation of the output level as the frequency of an operator increases.

void OPL2::setScalingLevel(byte channel, byte operatorNum, byte scaling);

Set the key scale level of the given channel and operator. This determines the attenuation of the output level as the frequency of the operator increases.

byte OPL2::getSustain(byte channel, byte operatorNum);

Get the sustain level of the given channel and operator. The lower the sustain value the louder the sound. Note that in order for the OPL2 to apply a sustain the sustain bit of the operator must be set using setMaintainSustain, oterwise sustain will not be applied and the envelope will continue with its release portion immediately after the decay period.

void OPL2::getSustain(byte channel, byte operatorNum, byte sustain);

Set the sustain level of the given channel and operator. The lower the sustain value the louder the sound. Note that in order for the OPL2 to apply a sustain the sustain bit of the operator must be set using setMaintainSustain, oterwise sustain will not be applied and the envelope will continue with its release portion immediately after the decay period.

byte OPL2::getSynthMode(byte channel);

Returns whether the given channel is using additive synth (AM) of frequency modulation (FM). By default each channel will operate in FM-synthesis mode.

• When a channel is put into additive synth mode the output of the two operators is added together
• In FM-synthesis mode only operator 2 will produce sound, but operator 1, the modulator, will be sent to the input of operator 2, the carrier, to modulate the frequency of operator 2

void OPL2::setSynthMode(byte channel, byte synthMode);

Set whether the given channel is using additive synth (AM) of frequency modulation (FM). By default each channel will operate in FM-synthesis mode.

• When a channel is put into additive synth mode the output of the two operators is added together
• In FM-synthesis mode only operator 2 will produce sound, but operator 1, the modulator, will be sent to the input of operator 2, the carrier, to modulate the frequency of operator 2

bool OPL2::getTremolo(byte channel, byte operatorNum);

Returns whether tremolo is enabled on the given channel and operator. When enabled tremolo causes the operator's amplitude to vibrate. By default this setting is disabled. When enabled normally this will cause the output level to fluctuate by 1.0 dB, but when deep tremolo is enabled by setDeepTremolo(true) then tremolos on all channels will be 4.8 dB.

void OPL2::setTremolo(byte channel, byte operatorNum, bool enable);

Apply amplitude modulation to a certain channel operator, causing a tremolo effect. The depth of the tremolo can either be 1 dB, or 4.8 dB. This is controlled by setDeepTremolo which is common to all operators. By default tremolo is disabled.

bool OPL2::getVibrato(byte channel, byte operatorNum);

Returns whether vibrato is enabled on the given channel and operator. Vibrato causes the frequency of an operator to fluctuate. By default this setting is disabled. When enabled, normally the frequency will vibrate by 7/100 of a semi-tone. When deep vibrato is enabled by setDeepVibrato(true) then vibrato on all channels will be 14/100 of a semi-tone.

byte OPL2::setVibrato(byte channel, byte operatorNum, bool enable);

Sets whether vibrato is enabled on the given channel and operator. Vibrato causes the frequency of an operator to fluctuate. By default this setting is disabled. When enabled, normally the frequency will vibrate by 7/100 of a semi-tone. When deep vibrato is enabled by setDeepVibrato(true) then vibrato on all channels will be 14/100 of a semi-tone.

byte OPL2::getVolume(byte channel, byte operatorNum);

Get the volume of the given channel and operator. For the volume; the lower the value, the greater the volume.

void OPL2::setVolume(byte channel, byte operatorNum, byte volume);

Set the output level of a channel's operator. The lower the value, the higher the output level.

byte OPL2::getWaveForm(byte channel, byte operatorNum);

Return the currently selected waveform for the given channel and operator. Note that the waveform select bit must be enabled on the OPL2 using setWaveFormSelect to allow for different waveforms per operator, otherwise all channels will use a sine wave.

Arguments

• channel - Index of the channel [0, MAX_CHANNEL]
• operatorNum - The operator for which to get the current wave form OPERATOR1 / MODULATOR or OPERATOR2 / CARRIER

Returns

byte The currently selected wave form for the operator

Value	Waveform
0
1
2
3

OPL Registers

Reads from register based at 0xE0, bits 0 through 2

See also

setWaveForm, getWaveFormSelect

void OPL2::setWaveForm(byte channel, byte operatorNum, byte waveForm);

Select the waveform to use for a certain channel operator. To take effect waveform selection must be enabled with setWaveFormSelect(true) first. By default each operator will use a sinewave.

Arguments

• byte channel - Index of the channel [0, MAX_CHANNEL]
• byte operatorNum - The operator for which to change the waveform OPERATOR1 / MODULATOR or OPERATOR2 / CARRIER
• byte waveForm - The wavefor to set for the operator [0, 3]

Value	Waveform
0
1
2
3

OPL Registers

This function alters bits 0 through 2 of register at base address 0xE0

See also

getWaveForm, setWaveFormSelect

bool OPL2::getWaveFormSelect();

Returns whether waveform selection is enabled on the OPL2. If true then setWaveForm can be used to select different waveforms per operator. If false then all operators will use a sinewave. By default this will be set to false.

void OPL2::setWaveFormSelect(bool enable);

Enable or disable waveform selection for each individual channel operator. If disabled then all operators will output a basic sine wave. By default wave form selection is disabled.