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@ -46,3 +46,12 @@ as of Furnace 0.6pre7, AY-3-8910 supports software PCM, where all 3 channels can
- this changes the port's mode to "write". make sure you have connected something to it.
- `2Fxx`: **write to I/O port B.**
- this changes the port's mode to "write". make sure you have connected something to it.
# chip config
## AY derivative modes
ay-3-810 was an absurdly popular chip that was blessed with many third-party clones, lincenced or not.
- the AY-3-8914 variant was used in Intellivision, which is pretty much an 8910 with 4 level envelope volume per channel and different register format.
- Yamaha YM2149 was an AY-3-8910 clone released in 1983. it's almsot identical to AY with minor differences being: higher hardware envelope step resolution (16 vs 32), half-clock mode when voltage level is low, much stronger DC offset, cleaner but softer output.
- Sunsoft 5B is YM2149 clone with half-clock mode forced on.