Add D0-D7 data bus (GPIOC), control signals _WR/_RD/_CS/_IC and address lines A0/A1 (GPIOF), and _IRQ input for the YMF262 interface. Fix PLL parameters (PLLM=8, PLLN=432, PLLQ=12) for correct 216 MHz operation from the 8 MHz HSE, and switch USB 48 MHz clock to PLLSAI.