3.2.1. C8051F12x Code Banking The C8051F12x family of devices have 128KB of Flash which is divided into 4 banks. Addresses in the range 0x00000 to 0x07FFF are mapped to first bank of Flash. Addresses in the range of 0x08000 to 0x0FFFF are mapped to one of the other three banks based on the settings of the PSBANK register.