YM2612 Registers: Difference between revisions

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==0x30-0x90 - Single operator==
==0x30-0x90 - Single operator control==


Each channel operators is configured with 7 registers.
Each channel operators is configured with 7 registers.
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|4
|4
}}
}}
==0xA0-0xB4 - Single channel control==
Like the 0x30-0x90 range, each register is tripled.
{|class="regdef"
|'''Address'''
|'''Part I'''
|'''Part II'''
|-
|$x0
|Channel 1
|Channel 4
|-
|$x1
|Channel 2
|Channel 5
|-
|$x2
|Channel 3
|Channel 6
|}
===0xAx - Frequency ===
The frequency is a 14-bit number, high part must be written in 0xA4 first, then lower part to 0xA0.
The three highest bit give the octave. The ten others give the position in the octave.
If channel 3 is in special mode (see register 0x27), one can control each channel 3 operators.
Operator 1 frequency is in 0xA2/0xA6.
Operator 2 frequency is in 0xA8/0xAC.
Operator 3 frequency is in 0xA9/0xAD.
Operator 4 frequency is in 0xAA/0xAE.
===0xB0 - Feedback and Algorithm===
{{8BitRegister
|Unused
|2
|Feedback
|3
|Algorithm
|3
}}
===0xB4 - Stereo and LFO===
{{8BitRegister
|Left
|1
|Right
|1
|AMS (Amplitude Modulation Sensitivity)
|2
|Unused
|1
|FMS (Frequency Modulation Sensitivity)
|3
}}
{|class="regdef"
|'''AMS Value'''
|'''dB'''
|-
|0
|0
|-
|1
|1.4
|-
|2
|5.9
|-
|3
|11.8
|}
{|class="regdef"
|'''FMS Value'''
|'''% of a halftone'''
|-
|0
|0
|-
|1
|~3.4
|-
|2
|~6.7
|-
|3
|~10
|-
|4
|~14
|-
|5
|~20
|-
|6
|~40
|-
|7
|~80
|}
[[Category:Audio]]

Latest revision as of 02:02, 4 August 2012

0x22 - LFO

Bit 7 6 5 4 3 2 1 0
Def Unused LFO Enable LFO Frequency


Value LFO Frequency
0 3.98
1 5.56
2 6.02
3 6.37
4 6.88
5 9.63
6 48.1
7 72.2

0x24/0x25 - Timer A

0x24

Bit 7 6 5 4 3 2 1 0
Def Timer A (bit 10-2)

0x25

Bit 7 6 5 4 3 2 1 0
Def Unused Timer A (bit 1-0)

0x26 - Timer B

Bit 7 6 5 4 3 2 1 0
Def Timer B

0x27 - Channel 3/6 and Timer control

Bit 7 6 5 4 3 2 1 0
Def Channel 3 Mode

0 : Normal

1 : Special

2/3 : Illegal

1 : Timer B Reset

0 : No effect

1 : Timer A Reset

0 : No effect

1 : Timer B overflow set the read register flag

0 : Timer B overflow don't set the read register flag

1 : Timer A overflow set the read register flag

0 : Timer A overflow don't set the read register flag

1 : Start Timer B

0 : Stop Timer B

1 : Start Timer A

0 : Stop Timer A

0x28 - Channel Operator control

Bit 7 6 5 4 3 2 1 0
Def Operator Unused Channel

0x2A/0x2B - DAC

0x2A

Bit 7 6 5 4 3 2 1 0
Def DAC Data

0x2B

Bit 7 6 5 4 3 2 1 0
Def 1 : DAC Enable

0 : DAC Disable

Unused

0x30-0x90 - Single operator control

Each channel operators is configured with 7 registers.

Address Part I Part II
$x0 Channel 1 Operator 1 Channel 4 Operator 1
$x1 Channel 2 Operator 1 Channel 5 Operator 1
$x2 Channel 3 Operator 1 Channel 6 Operator 1
$x4 Channel 1 Operator 2 Channel 4 Operator 2
$x5 Channel 2 Operator 2 Channel 5 Operator 2
$x6 Channel 3 Operator 2 Channel 6 Operator 2
$x8 Channel 1 Operator 3 Channel 4 Operator 3
$x9 Channel 2 Operator 3 Channel 5 Operator 3
$xA Channel 3 Operator 3 Channel 6 Operator 3
$xC Channel 1 Operator 4 Channel 4 Operator 4
$xD Channel 2 Operator 4 Channel 5 Operator 4
$xE Channel 3 Operator 4 Channel 6 Operator 4


0x3x register

Bit 7 6 5 4 3 2 1 0
Def Unused DT1 (Detune) MUL (Multiple)


MUL multiplies the overall frequency by it's value (except for the 0 value which multiply by 0.5)

DT1 gives small variations from the overall frequency x MUL.


Value Multiplicative effect
0 No change
1 x(1 + E)
2 x(1 + 2E)
3 x(1 + 3E)
4 No change
5 x(1 - E)
6 x(1 - 2E)
7 x(1 - 3E)


0x4x register

Bit 7 6 5 4 3 2 1 0
Def Unused Total level (envelope's highest amplitude)

Value is between 0 (largest) and 127 (smallest)

A change of one unit is about 0.75dB


0x5x register

Bit 7 6 5 4 3 2 1 0
Def RS (Rate scaling) Unused AR (Attack rate)


0x6x register

Bit 7 6 5 4 3 2 1 0
Def AM (Amplitude modulation enable) Unused D1R (first decay rate)


0x7x register

Bit 7 6 5 4 3 2 1 0
Def Unused D2R


0x8x register

Bit 7 6 5 4 3 2 1 0
Def D1L RR


0x9x register

Bit 7 6 5 4 3 2 1 0
Def Unused SSG-EG

0xA0-0xB4 - Single channel control

Like the 0x30-0x90 range, each register is tripled.

Address Part I Part II
$x0 Channel 1 Channel 4
$x1 Channel 2 Channel 5
$x2 Channel 3 Channel 6


0xAx - Frequency

The frequency is a 14-bit number, high part must be written in 0xA4 first, then lower part to 0xA0.

The three highest bit give the octave. The ten others give the position in the octave.


If channel 3 is in special mode (see register 0x27), one can control each channel 3 operators.

Operator 1 frequency is in 0xA2/0xA6. Operator 2 frequency is in 0xA8/0xAC. Operator 3 frequency is in 0xA9/0xAD. Operator 4 frequency is in 0xAA/0xAE.


0xB0 - Feedback and Algorithm

Bit 7 6 5 4 3 2 1 0
Def Unused Feedback Algorithm


0xB4 - Stereo and LFO

Bit 7 6 5 4 3 2 1 0
Def Left Right AMS (Amplitude Modulation Sensitivity) Unused FMS (Frequency Modulation Sensitivity)


AMS Value dB
0 0
1 1.4
2 5.9
3 11.8


FMS Value % of a halftone
0 0
1 ~3.4
2 ~6.7
3 ~10
4 ~14
5 ~20
6 ~40
7 ~80
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