Sonic_knuckles_wsonic3.bin =link= -

When the lock‑on cartridge is inserted, the CPLD asserts for the lock‑on ROM for the address range 0xA12000–0xA13FFF (the “extension window”). All other addresses fall through to the underlying Sonic 3 ROM.

| Address | Region | Owner | |---------|--------|-------| | 0x000000‑0x9FFFFF | 10 MiB (virtual) | (read‑only). | | 0xA00000‑0xA1FFFF | 128 KiB | VRAM (write‑only to VDP). | | 0xA12000‑0xA13FFF | 8 KiB | Lock‑On RAM (holds glue loader). | | 0xFF0000‑0xFFFFFF | 64 KiB | Work RAM (WRAM) – custom code lives here after relocation. | sonic_knuckles_wsonic3.bin

The project used the same lock‑on architecture, but swapped the upper 2 MiB (the lock‑on chip) for a custom‑written program. The resulting binary is what you see as sonic_knuckles_wsonic3.bin . When the lock‑on cartridge is inserted, the CPLD

The file could introduce new gameplay mechanics or adjust existing ones to more closely align with the experience of Knuckles' Chaotix. | | 0xA00000‑0xA1FFFF | 128 KiB | VRAM

– sonic_knuckles_wsonic3.bin is the “combined” lock‑on ROM that lets the original Sonic & Knuckles cartridge run the Sonic 3 game (or a fan‑made “W‑Sonic‑3” hack) as if the two cartridges were physically linked. The file is a 4 MiB binary that mirrors the hardware layout of the lock‑on chip, contains a 2 MiB Sonic 3 program image, a 2 MiB Sonic & Knuckles “extension” image, and a small “glue” loader that maps the two halves together at runtime.