Release MSXnano v1.6 — SD boot menu, FAT32, SCC+ & HDMI stereo · Papipapito/MSXnano

MSXnano grows up: a full SD boot menu, FAT32, real SCC+ (doubled!) and HDMI stereo.

🗂️ Boot menu — SD file browser

File-Hunter-style browser that starts before the OS: filter tabs [R]OM / [D]SK / [A]LL, long filenames with marquee, subdirectories, entry counter.
Launch .ROM straight into the megaram: mapper auto-detection + GoodMSX filename tags, progress bar, confirm screen.
Launch .DSK via Nextor disk emulation — fully automatic and invisible (no helper files to prepare), with fragmentation check.
FAT16 + FAT32, auto-detected per partition (hybrid cards work; TAB switches partitions).
ESC continues the normal boot to Nextor/MSX-DOS. S opens settings, W WiFi config.

Option	What it does
Second SCC	Second SCC+ chip in the free slot (dual-SCC players/trackers)
Stereo Sound	HDMI stereo: PSG1+SCC1+OPLL left / PSG2+SCC2+OPLL right
Pantalla 16:9	HDMI aspect signalling 4:3 / 16:9 (the TV decides pillarbox vs stretch)

Real SCC+ (SCC-I): B800h window, BFFEh mode register, independent channel-5 wave; wave-RAM read-back fixed (software SCC detection works now).
Second SCC+ and second PSG (ports 10h-12h, OCM standard) — verified on hardware with tools/scctest/SCCTEST.COM (detection + per-chip stereo tone test).
True L/R stereo over HDMI.

FPGA timing closure: 54 MHz domain now closes with positive slack (SD-companion CDC constraints + kanji decode retime).
build.bat bundles the new boot menu into the BIOS pack automatically.
Z80-level emulation test harness for the menu's FAT16/FAT32 code.

msxnano.fs (asset below) → SPI flash 0x000000 (Gowin Programmer, External Flash mode)
BIOS pack → 0x200000 — goauld_rom_int.bin
BL616 FPGA-Companion + optional ESP-01S: unchanged, see the README

📼 Demo video: msxnano_v16_menu_demo.mp4 in the assets below.

Source: branch MSXNano_Menu. Built on jabadiagm's goauld core (GPLv3). Claude (Anthropic) collaborated on this release.

2026-06-10.20-51-07.-.Trim.mp4