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RetroBIOS

EmuSCV

EmuSCV emulates Epoch Super Cassette Vision. It reads 1 file, 1 of them required: without a required file it does not start games.

About this profile
Detail Value
Type libretro
Classification Community fork
Source https://github.com/wzcwzc/emuscv
Upstream http://takeda-toshiya.my.coocan.jp/
Version 0.12.20220726135800, stated in Makefile.libretro
Revision wzcwzc/emuscv@6d6e4594d798
Profiled 2026-03-23
Profile YAML, JSON
Cores emuscv
Systems Epoch Super Cassette Vision
Install this emulator's files

The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell
&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator emuscv
Platform details

  • cpu: NEC UPD7801G

  • bios_mapping:

    • upd7801g: {'target': '0x0000-0x0FFF (CPU internal ROM, 4 KB)', 'format': 'raw binary', 'source_ref': 'src/vm/scv/memory.cpp:249-254', 'notes': 'Memory map from memory.cpp:initialize():\n 0x0000-0x0FFF BIOS ROM (read-only)\n 0x2000-0x3FFF VRAM (8 KB)\n 0x8000-0xFF7F Cartridge ROM (up to 4 banks of 32 KB)\n 0xFF80-0xFFFF CPU internal RAM (128 bytes)\nFont data lives inside the BIOS at offset 0x200, accessed via\nget_font() for the VDP character rendering (src/vm/scv/vdp.cpp).\n'}

  • cartridge_loading:

Technical notes

Libretro port of eSCV by Takeda Toshiya (Common Source Code Project), ported to libretro by MARCONATO Maxime. Upstream source mirrored at https://github.com/tautologico/common-src-project (src/vm/scv/).

BIOS loading in src/vm/scv/memory.cpp:initialize() (lines 74-243). Tries filenames in order: upd7801g.s01, upd7801g.bin, upd7801g.bios, bios.rom, bios.bin. First successful open wins. Upstream eSCV uses only BIOS.ROM (uppercase), and the libretro port renamed and added fallback aliases.

The BIOS is read as 0x1000 (4096) bytes into the bios[] array, mapped read-only at CPU address 0x0000-0x0FFF (UPD7801 internal ROM area).

When CHECKBIOS core option is YES, the core computes MD5 of the loaded data and compares against 635a978fd40db9a18ee44eff449fc126. If the hash does not match, the BIOS is rejected (zeroed out, bios_present=false). When CHECKBIOS is AUTO (default) or NO, any file content is accepted. The log message for AUTO says "automatic (yes)" but the code skips the check (code bug: != YES_VAL at line 80).

The font/character data is embedded within the BIOS at offset 0x200 (memory.h get_font() returns bios + 0x200). No separate font ROM file.

The core can start without BIOS (supports_no_game=true) but shows "BIOS not found" or "Bad BIOS" on the OSD. Games will not run without it.

The .info declares firmware_count=1, firmware0_opt=false. Matches code.

Files

Section titled “Files”

1 file: 1 required, 0 optional.

In this collection: 1 in repo and 0 missing.

Required

Section titled “Required”

upd7801g.s01 required in repo

  • System: Epoch Super Cassette Vision
  • Aliases: upd7801g.bin, upd7801g.bios, bios.rom, bios.bin
  • UPD7801G internal ROM (BIOS). Mapped at 0x0000-0x0FFF. Contains character font at offset 0x200.
Hashes, validation and source

Next steps

Section titled “Next steps”
.

Maintained by Abdess on GitHub. Report a problem.

Packs from release v2026.10.10, .

MIT for the tooling and metadata. BIOS and firmware files are third-party system software, preserved for personal backup, archival and interoperability.