Lesson 3: Exploring the Cellular Communication Module OpenCPU

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Lesson 3: Exploring the Cellular Communication Module OpenCPU [Copy link]

What is OpenCPU

"Xiao Wang, what is OpenCPU?", "I know OpenCPU, it's just opening a cup", ...

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Let's get back to the point. OpenCPU was originally designed by students from USTC as an open computer system based on a 32-bit RISC CPU. This system allows users to perform partial structural design, module design, I/O operations, etc. Later, all its technical documents and source codes were published online in a shared manner, becoming an open source CPU design, so it was named OpenCPU. OpenCPU is applied to wireless communication modules mainly to allow users to share the processor and FLASH resources in the module. Figure 1 shows the normal application mode. Usually, the user application runs on an external MCU and uses the serial port to send AT commands and feedback to achieve interaction with the module. Figure 2 shows the OpenCPU mode. The user program can treat the module as an MCU. The entry function is changed from main to opencpu_task_main (the name depends on the specific module). The interaction with the module is achieved through function calls.

To put it simply, in the OpenCPU mode, the module carried out a thorough "anti-corruption struggle", and the confiscated resources were provided to the majority of users. Users do not need an external MCU, and the corresponding power supply and peripheral devices can naturally be saved. In short, within the module, user programs can enjoy the treatment of separate houses, cars, wives, food, accommodation, and mistresses, and live a shameless and happy life from then on.

Advantages of OpenCPU mode over normal mode

As can be seen from the comparison between Figures 1 and 2, the main difference between the two is that OpenCPU mode does not require an external MCU, which brings the following benefits:

• Quickly develop embedded applications and shorten product development cycle
• No need for external processor, memory and discrete and related design costs
• Reduce the actual size of the terminal product
• Reduce product power consumption
• Remote over-the-air wireless upgrade
• Anti-copy technology enhances product security
• Improve product market cost performance and enhance product competitiveness

Summary of user available storage resources in OpenCPU mode of China Mobile IoT cellular communication module

Serial number	Communication module type	Module model[/a lign]	FLASH	RAM
1	NB-IoT	[align=le ft]M5310-A	180KB	30KB
2		M5311 [/td][td =85] 128KB	256KB
3	2G	[align=le ft]M6312	1MB	4MB
4		M6313 [/td][ td=85] 1MB	4MB
5	4G	M8321	20MB	15MB