3 ms·

Game Boy Color has a secret video mode where you can directly drive the LCD from the cartridge slot. CPU completely halts, so you can't use the joypad or sound

• bbbbbr 6mo ago
  That CPU halting only applies for PGB mode 1. In PGB mode 2 the CPU is still able to run (within a limited address range) and can use register FF75 "PGBIO" for limited input and output on some cartridge pins (and/or the link port for IO).