28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
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# Philips SAA1099
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this was used by the Game Blaster and SAM Coupé. it's pretty similar to the AY-3-8910, but has stereo sound, twice the channels and two envelopes, both of which are highly flexible.
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# effects
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- `10xy`: set channel mode.
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- `x` toggles noise.
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- `y` toggles square.
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- this effect affects either the first 3 or last 3 channels, depending on where it is placed.
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- `11xx`: set noise frequency.
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- this effect affects either the first 3 or last 3 channels, depending on where it is placed.
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- `12xx`: setup envelope. this is a bitmask.
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- bit 7 toggles the envelope.
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- bit 5 toggles whether to use a fixed frequency or lock to the frequency of channel 2 or 5.
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- bit 4 sets the envelope resolution.
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- bits 1 to 3 set the envelope shape:
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- `000`: always off
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- `001`: always on
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- `010`: down
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- `011`: down loop (saw)
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- `100`: up down
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- `101`: up down loop (triangle)
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- `110`: up then off
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- `111`: up loop (reverse saw)
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- bit 0 sets whether the right output will mirror the left one.
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- this effect affects either the first 3 or last 3 channels, depending on where it is placed.
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