STM32 GPIO Registers

• Port Direction Registers
• Port Speed Registers
• Port Output Type Register
• Port Output Data Register
• Port Input Data Register
• Some Other configuration registers

All the GPIO Registers are connected to the Processor over the System Bus. AHB1 Bus and frequency depends on the Controller.

And GPIO Ports n depends on the Controller it can vary based on the controller to controller in the Same STM32 itself.

Each Peripherals having the Register section in the user manual. There we can find the register related info.