YM2612 Registers

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Revision as of 22:09, 29 July 2012 by ElBarto (talk | contribs) (Created page with "=Port= ==Writing== {|class="regdef" |'''Description''' |'''Zone''' |'''Address''' |- |rowspan="2"|Part I address (A0) |Z80 |$4000 |- |M68K |$A04000 |- |rowspan="2"|Part I ad...")
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Port

Writing

Description Zone Address
Part I address (A0) Z80 $4000
M68K $A04000
Part I address (D0) Z80 $4001
M68K $A04001
Part I address (A1) Z80 $4002
M68K $A04002
Part I address (D1) Z80 $4003
M68K $A04003

Reading

Reading from any of the port will return the status register.

Bit 7 6 5 4 3 2 1 0
Def 1 : Busy

0 : Ready for new data

Unused 1 : Timer A Overflow

0 : Not overflow

1 : Timer B Overflow

0 : Not overflow

Registers

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

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

0x30

Bit 7 6 5 4 3 2 1 0
Def Unused DT1 MUL
Bit 7 6 5 4 3 2 1 0
Def Unused Total level (envelope's highest amplitude)
Bit 7 6 5 4 3 2 1 0
Def RS (Rate scaling) Unused AR (Attack rate)
Bit 7 6 5 4 3 2 1 0
Def AM (Amplitude modulation enable) Unused D1R (first decay rate)
Bit 7 6 5 4 3 2 1 0
Def Unused D2R
Bit 7 6 5 4 3 2 1 0
Def Unused SSG-EG