Android AP and BP

Most phones contain two processors. Operating systems, user interfaces, and applications are performed on the application Processor (AP) (Application processor), with the AP generally using the arm chip's CPU. and the mobile radio frequency communication control software, then runs on another separate CPU, this CPU is called baseband Processor (BP) (baseband processor).
The main reason for the RF function on BP is that the RF control functions (signal modulation, coding, RF displacement, etc.) are highly time-dependent. The best way to do this is to put these functions on a main CPU and the main CPU is running the real-time operating system. Another advantage of using BP is that once it is designed and certified as well, no matter how your operating system and application software changes, it can perform functions correctly (its communication function). In addition, operating system and driver bugs will not cause the device to send catastrophic data to the mobile network. (FCC requirements) because the AP and BP are separate devices, the handset designer can design the user interface and application software more freely. 2) Mobile phone developers, such as Motorola, will develop the mobile phone package into the AP and BP two parts, running on the application Processor (AP) package called AP package, including operating system, user interface and applications; The packages associated with baseband Processor (BP) are called BP packages, including communication control software for baseband modems. Accordingly, the so-called refresh of the mobile AP and the BP file is to update the two packages to the phone. For the convenience of the brush machine, there are also ap,bp files and flex files (the phone's parameter profile) together as a package.