Highlights
- Added YM2203 playback using the compatible JT12/JT03 configuration
- Added JT49 SSG support
- Added VGM command
0x55 - Added YM2203 header clock support at
0x44–0x47 - Added dynamic fractional YM2203 chip CEN
- Added deterministic reset handling for JT03, JT49, and JT12 startup pipelines
- Added SegaPCM playback through the normal DDR path
- Added SegaPCM header clock tracking
- Enabled concurrent playback support for:
- YM2612
- SN76489 PSG
- YM2151 / JT51
- YM2203 / JT49
- SegaPCM
- Restored the historical MD audio profile
- Normalized MD-family and arcade-family output levels independently
- Balanced YM2203 FM against SSG using an FM x4 scale
- Simplified the release OSD
Release OSD
- Load VGM
- Audio Gain
- SegaPCM Audio
- Normal
- PCM Only
- FM Only
- Reset
Audio Gain Normal/Boost applies to the MD family (YM2612 + PSG). The release SegaPCM feed is fixed to Hold, and SegaPCM polarity is Normal.
Validation
- Hardware tested on MiSTer-compatible hardware
- YM2612 FM, SN76489 PSG, and YM2612 DAC playback confirmed
- MD Audio Gain Normal and Boost confirmed
- YM2151 / JT51 playback confirmed
- YM2203 FM and JT49 SSG playback confirmed
- SegaPCM normal-DDR playback confirmed
- Normal, FM Only, and PCM Only selectors confirmed
- Hardware playback checked with Space Harrier, Fantasy Zone, After Burner, and OutRun-family material
- Icarus and Verilator regressions passed
- No Mac Quartus build was performed; the attached RBF is the Windows-built, hardware-tested binary
Known issues
- The first playback of “Maximum Power” immediately after loading a fresh RBF may contain a buzzing artifact
- Some early YM2151 VGM files, including Quartet, may produce load-dependent sound differences; investigation is ongoing
- Mega CD / RF5C164 is not supported
- 32X PWM is not supported
Development note
Existing completed devices may be disabled in lab builds during new-chip bring-up. Release builds enable all supported production devices concurrently. Lab-only audio stubs must not be used for release builds.