Concurrent AT Command Control System With Priority

This paper describes a collateral AT command control method in macro. In this way, we can greatly enhance the performance of the AT between the master controller and modem, modular AT control flow, reduce the degree of coupling between application modules, the entire AT commands to control like black box operation.AT command is more mature modem control commands, is mainly used to control the modem module. AT command contains instructions and data, is a very flexible and extensible instruction set. Via AT commands, you can complete the interaction between the master controller and the slave. AT command is a command-response based mechanisms agreement. Due to the command-response based mechanism, AT command execution flow is usually designed as a linear serial operation. That is, when a command is issued, next instruction will be send after a response is received. Parallel operation of modern operating system can being reflected in AT design, that leads the traditional AT design method is complex and coupled high, brought to the entire modern operating system-based master module via AT commands manipulate modem design complexity. On the mobile phone software development work with the author, traditional dual standby module through the AT command control is very complex, every upper layer application needs to organize AT strings by it self then call the interface to send out when it wants to send an AT command; the response returned needs to pass to the upper called application one by one, then it can be decided by the uppler layer application if it is what it needs. At the same time, due to the complexity and high coupled of the design, module fault tolerance is greatly reduced, for example, it always happened that application A or B responsed wrong return, this cause the system issues abound. When bugs were found during the system testing period, to solve a problem, often caused another. So AT command designing is the main reason affecting the quality of production design.Of observed AT command send to the modem end will also be distributed to different modules, when an AT command is sent to the modem before a response is not received, then send another AT command, two AT commands return will be linear. This brings the theoretical feasibility of concurrent design of the module to the AT command operation. I designed a single module, which has responsibility for the whole AT command generation and distribution, the application when need to send the AT command just design good looking forward to the return value and a return handle. The AT system module returns the response to the called upper layer application based on the expected return value and return handle, This can avoid the confusion. Then through the design of the buffer pool, it can store5AT commands one-time. All commands send out before the first response is received, which in turn issued the macro parallel operation. By queue storage operation at the same time, make the signal priority design to be possible. Signal queue priority queuing, enabling preemptive instruction on the macro side of the observation from the application layer.I make the upper layer designer do not need to think the not belonging response will send to itself, and do not need to think if the wrong response it need to send to others throw these way. Due to the return type judging resolved the problem that analytic function of AT return is very long and low efficiency. Through these methods, the software design to reduce module coupled degrees, reduce the difficulty of the application calls the AT command design, enhance product quality.