# Philips SAA1099

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. The envelopes work like this:
- an instrument with envelope settings is placed on channel 2 or channel 5
- an instrument that is used as an "envelope output" is placed on channel 3 or channel 6 (you may want to disable wave output on the output channel)

# effects

- **`10xy`**: set channel mode.
  - `x` toggles noise.
  - `y` toggles square.
  - this effect affects either the first 3 or last 3 channels, depending on where it is placed.
- **`11xx`**: set noise frequency.
  - this effect affects either the first 3 or last 3 channels, depending on where it is placed.
- **`12xx`**: setup envelope. this is a bitmask.
  - bit 7 toggles the envelope.
  - bit 5 toggles whether to use a fixed frequency or lock to the frequency of channel 2 or 5.
  - bit 4 sets the envelope resolution.
  - bits 1 to 3 set the envelope shape:
    - `000`: always off
    - `001`: always on
    - `010`: down
    - `011`: down loop (saw)
    - `100`: up down
    - `101`: up down loop (triangle)
    - `110`: up then off
    - `111`: up loop (reverse saw)
  - bit 0 sets whether the right output will mirror the left one.
  - this effect affects either the first 3 or last 3 channels, depending on where it is placed.