Brew advanced and proficient-3G mobile value-added business operation, customization, and development-37-brew software layers in mobile phones

Brew is an execution environment on mobile phones and an application framework. Brew
It provides an efficient, low-cost, and scalable application execution environment, focusing on developing applications that can seamlessly implant any actual handheld device. Unlike high-end products built on operating systems that have high requirements on memory space, processor speed, and related hardware, brew can run on various levels of device types.

The application execution environment provided by the BREW Platform is similar to the operating system on the PC (especially in brew4.x and later versions), shielding the differences between underlying hardware devices and network protocols, allows handheld devices to download a specified type of applications or games, without having to focus on different implementations of underlying hardware devices or network protocols. At the same time, through brew
Platform-independent interface features, suppliers can provide a complete set of information, business, and entertainment functions.

 

The bottom layer is the hardware device layer, which mainly includes hardware devices and processors in mobile phones. All terminals supporting brew run adopt the ARM architecture based on embedded RISC microprocessor. The operating system layer is above the hardware device layer. Generally, mobile phones with single-core structures use real-time operating systems to provide basic platform services such as system control, file system access, power management, and security. Common real-time operating systems include Rex and real-time embedded Linux.

The operating system layer is based on the software layer. All device drivers and hardware-related functions are implemented at this layer. Device Drivers are used to control hardware and provide a logical abstraction for upper-layer development, so that upper-layer developers do not need to consider the following specific hardware. They can directly control the hardware through the driver interface, this increases the scalability of the system. For example, USB and serial port communication, LCD display driver, speaker and microphone functions, etc.

The upstream layer is an important Layer Related to brew. It includes two interface layers: chip interface layer and mobile interface layer. The chip interface layer provides chip-related APIs and supports various expansion services provided by the communication baseband processor. Such as Bluetooth, audio and image encoding and decoders, network services, telephone services, location services, and file system services. The OEM layer during brew transplantation mainly refers to this layer. The OEM layer communicates with the application layer and the bearer protocol stack, LCD (LCD), keyboard, Speaker (speaker), SIM/USIM, and other devices through callback functions and program application interface functions. One of the important tasks of the OEM layer is to encapsulate the state machine in the lower layer into the State required by the application.

The functions provided by the mobile interface layer are basically irrelevant to the chip, that is, all functions except the chip interface layer. For example, the address book function, display-related functions (such as fonts, colors, images, etc.), the ringtone function, string processing, and memory management functions. The OEM layer for brew porting also contains some features in this layer, but most of the features in this layer are implemented by the basic library in the brew execution environment.

The above layer is the aee layer, specific brew applications and extended applications.