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feat(audio): implement PSG noise channel 4

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0xrsydn 2026-10-07 02:51:46 +07:00
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docs/status.md
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@ -80,7 +80,8 @@ Update this file when a feature lands or a limit is removed.
- RegisterRamReset supports disabled sound and disconnected serial initialization, including the common `r0=0xff` request.
- Direct Sound A/B support timer-driven FIFO playback, stereo digital levels, and DMA1/A or DMA2/B refill blocks.
- PSG pulse channels 1 and 2 support independent nominal frequency/duty playback, length, envelope, status, and stereo mixing. Channel 1 also supports sweep.
- Channel 3–4 triggers and unsupported serial operations produce explicit address/value diagnostics with whole-access and block-store rollback.
- Noise channel 4 supports nominal 7/15-bit generation, divider clocks, shared length/envelope behavior, status, and stereo mixing.
- Wave channel 3 triggers and unsupported serial operations produce explicit address/value diagnostics with whole-access and block-store rollback.
- ROM windows with scanline capture, keyboard input, focus-loss release, bounded execution slices, and interactive keypad wake from STOP.
- Optional ROM-window frame limits and an original input-test ROM generator.
- Headless JSON ROM suites with PC or VBlank completion, register/CPSR/memory/pixel assertions, scheduled buttons, bounded budgets, and structured failure reports.
@ -137,8 +138,8 @@ Horizontal window comparators retain four-cycle event history.
Sprite rows prepare one line ahead with a whole-row cycle40 sample and nominal per-row work limits.
Individual fetch timing, hardware-accurate work cutoffs, video-bus contention, and per-pixel color composition remain unimplemented.
There is no host audio output or cartridge save support.
The [audio subset](hardware/audio.md) supports Direct Sound, both PSG pulse channels, idle channel 3–4 state, wave banking, and instantaneous digital mixing.
It does not yet provide a continuous sample stream. Channel 3–4 playback and unverified sound-DMA pairings remain diagnostic.
The [audio subset](hardware/audio.md) supports Direct Sound, both PSG pulse channels, noise channel 4, idle wave channel 3 state, and instantaneous digital mixing.
It does not yet provide a continuous sample stream. Wave channel 3 playback and unverified sound-DMA pairings remain diagnostic.
PSG timing and signed mixing are nominal; hardware startup edges and analog behavior remain unverified.
The [serial initialization subset](hardware/serial.md) supports idle normal data and disconnected general-purpose pins, not active transfers.
Mapped I/O covers DMA, timers, interrupts, WAITCNT, display control/status, background control/scroll/affine registers, window/effect registers, KEYINPUT/KEYCNT, POSTFLG, and HALTCNT.
@ -150,7 +151,7 @@ ROM files can run in bounded terminal mode or a window with the original BIOS re
ROM windows have no demo-specific startup checks. Input is sampled between bounded execution slices.
Audio, saves, and external BIOS loading remain unavailable. ROM loading does not establish commercial-game compatibility.
A local Emerald run now completes its all-device reset and master sound enable.
It also passes both pulse triggers, then stops explicitly at noise channel 4 (`0x0400007d`).
It also passes the pulse and noise triggers, then stops explicitly at GPIO serial interrupt enable (`0x04000135`).
No title-screen, gameplay, or audible-game compatibility is established.
Its captured startup frames do not establish title-screen or gameplay compatibility. See [the startup result](research/emerald-reset.md).
See [cartridge loading](hardware/cartridge.md) for file limits, step budgets, and exit status.