Design And Implementation Of Simulative MCU In M2M Wireless Module

M2M(Machine to Machine) wireless module is the core unit of M2 M terminal devices. Normally wireless device architecture is based on MCU and M2 M wireless module. Application code is running inside MCU and communicating with M2 M module via UART interface with relative AT commands, also collecting data or realizing some functions via GPIO pins, I2 C interface, SPI interface, UART interface, ADC interface, Keypad interface, and so on, which are from module end.This paper will analyze deeply the basic methods of communication between MCU and wireless module, as well as compiling and running of embedded application. Inside of wireless module, the rule of MCU app could be replaced by embedded application which could save the cost and size of device.The main works in this thesis are as follows:(1) According to actual application scenario, based on SIM800 platform, this paper gives an idea that is, putting MCU app code into module memory.(2) Virtual hardware layer is realized including ROM, RAM, timer, UART, GPIO, and so on. These resources are accessed via API functions which will control real interfaces of module.(3) Pointer is designed to access app space from core layer, also help app layer doing system allocation. An independant C library is available to communicate between core layer and app layer only with several message interfaces. Core code and app code are separated and independant for each other. Even there has a big modification in core file, the customer does not need to rebuild or recompile app code.(4) Based on above solution, design a sample code, and verify this architecture.This solution will be available in M2 M wireless terminal device, replacing MCU and module solution but module only.This solution will save external MCU, with good cost performance and competitiveness. Also, by saving MCU and related components, as well as simplifying circuit and layout, the current consumption will be decreased. For developer, C language is same but no need to access MCU registers, only use API functions, this solution will save development time and make development easier. With multi-task in RTOS system, the developer could realize complex application, reach product functions. So, this is an effective solution.