The literal meaning of single-chip microcomputer is a single-chip microcomputer, which is a microcomputer system composed of a processor, memory and necessary external devices integrated on a semiconductor chip. Single-chip microcomputers are mostly used for control in practical applications, so it is more appropriate to call them microcontrollers (MCU).
The processor in the single-chip microcomputer usually only includes a central processing unit (CPU) to meet the demand. Some high-performance or special-demand microcontrollers may also include digital signal processors (DSP) or other processor cores. The memory of the one-chip computer includes read-only memory ROM and random access memory RAM. ROM is now basically using flash memory (FLASH). Many single-chip microcomputers provide methods to erase and write FLASH for users to use in programs. FLASH is no longer a ROM in the traditional sense, but more like a "solid state" of a single-chip microcomputer. hard disk".
The external devices of the single-chip microcomputer usually include timers, serial communication ports, digital-to-analog converters, analog-to-digital converters, pulse width modulators, etc., which are customized in the chip according to needs. After all, there are too many types of peripherals, but the chip area is limited, and it is impossible to integrate all peripherals into the chip due to cost considerations, and usually only the most commonly used peripherals are integrated on it. The most commonly used peripherals are timers, which are found in almost all microcontrollers.
The second is the serial port, which is available in quite a few single-chip microcomputers. Some more general single-chip microcomputers will also integrate more devices or interfaces, such as integrated circuit internal communication interfaces, synchronous serial ports, etc. The single-chip microcomputer used for motor control has ADC and PWM. MCUs with higher performance or specific requirements will also have video interfaces, liquid crystal interfaces and integrate corresponding processors or controllers. Of course, high performance and more versatility also brings high costs. Therefore, the selection of single-chip microcomputer should be considered comprehensively according to the needs, and should not be greedy for perfection.
The full English name of ARM is Advanced RISC Machines, that is, Advanced Reduced Instruction Set Processor, which is a general term for a series of well-known microprocessors designed by Acom Computer Co., Ltd. of the United Kingdom. Because the industry is used to calling it ARM, this series of microprocessors are called ARM processors, and its design company is called ARM company, but few people know its real name.
ARM itself does not produce microprocessors, it just authorizes the processors it designs in the form of IP cores (that is, design drawings, documents and other intellectual property rights) to many semiconductor manufacturers such as Intel, STMicroelectronics, Samsung, etc. , semiconductor manufacturers integrate relevant memory, peripherals and other necessary components according to their needs and their respective advantages, and produce single-chip microcomputers or other chips for sale. And ARM extracts a certain authorization fee from it to support and develop the company. So to be precise, ARM has no direct relationship with the microcontroller. In the field of single-chip microcomputer, it is just an excellent microprocessor core contained in a type of single-chip microcomputer.
1. In terms of software,
this should be the biggest difference. The operating system was introduced. Why introduce an operating system? what is the benefit?
1) Convenience. It is mainly reflected in the later development, that is, the application program is directly developed on the operating system. Unlike single-chip microcomputers, everything has to be rewritten. The early operating system transplantation work still needs to be done by professionals.
2) Security. This is a feature of LINUX. The kernel of LINUX is separated from the memory management of the user space, and the system will not die due to a single program error by the user. This has not been seen in the software development of single-chip microcomputers.
3) Efficient. Introduce a process management and scheduling system to make the system run more efficiently. In the development of traditional single-chip microcomputers, most of them are interrupt-based front-end and back-end technologies, which have limitations in the management of multi-tasks.
2. In terms of hardware,
the current 8-bit single-chip microcomputer technology hardware is also developing very fast, and many very powerful single-chip microcomputers have also appeared. But there are still some gaps compared with 32arm.
Most arm chips integrate SDRAM, LCD and other controllers into the film. In 8-bit machines, most of them need to be expanded externally. In general, a single-chip microcomputer is a microcontroller, and arm is obviously already a microprocessor.