Why must the selection of microcontrollers be considered?
Answer: The selection of microcontrollers is an important and labor-intensive task. If the microcontroller model is chosen appropriately, the microcontroller application system will be economical and reliable in operation; if the selection is inappropriate, it will lead to economic waste, affect the normal operation of the microcontroller application system, and may even fail to achieve the pre-designed functions.
What hazards arise from improper microcontroller selection?
Answer: For a microcontroller application system that has already been designed, its technical requirements and system functions should be very clear. If a microcontroller with too few functions is selected, the application system will be unable to complete its control tasks; however, if a microcontroller with overly powerful functions is chosen, it will not only be unnecessary but also lead to resource waste without improving the performance-to-price ratio.
What benefits come from correctly selecting a microcontroller?
Answer: By mastering and applying the principles of correct microcontroller selection, one can choose the microcontroller that best fits the application system, ensuring the application system has the highest reliability, optimal performance-to-price ratio, longest lifespan, and best upgrade potential.
What are the general principles for microcontroller selection?
Answer: The general principles for selecting microcontroller chips are:
“The chip should have (functionality or quantity) slightly greater than the design requirements,” “The design requirements should be met as much as possible (using) the chip (minimizing the use of peripheral devices),”
“Choose large (well-known manufacturers) over small, choose many (abundant supply) over few, choose reputable (well-known brands) over obscure (unknown manufacturers), choose affordable (low price) but good (quality assurance).”
How to select a microcontroller?
When selecting a microcontroller, it is mainly considered from three aspects: the technicality, practicality, and development potential of the microcontroller application system.
(1) Technicality: The selection of the microcontroller chip should be based on its technical specifications to ensure the application system operates reliably under certain technical indicators;
(2) Practicality: The selection of the microcontroller manufacturer should consider supply channels, reputation, etc., to ensure the application system can operate reliably and for a long time;
(3) Development potential: The selected microcontroller should have reliable development tools, such as programming tools and simulation debugging methods.
From a technical perspective, what is the general principle for microcontroller selection?
Answer: From a technical perspective, the general principle for microcontroller selection is to determine whether a microcontroller can complete the predetermined control of the system or if additional integrated circuits are needed to achieve system control.
From a technical perspective, how should the peripheral ports of a microcontroller be selected?
Answer: This depends on how many different types of I/O methods are used in the selected microcontroller’s I/O ports. For example, whether the microcontroller includes the following I/O methods or devices:
(1) SR232C terminal;
(2) Switches, relays, keyboards;
(3) Sensors, such as temperature, pressure, flow, light, voltage, etc.;
(4) Sound alarms;
(5) Displays, such as LED, LCD, etc.;
(6) A/D or D/A converters;
(7) Other I/O methods or functional devices.
During selection, if certain I/O methods or devices are required in the designed microcontroller application system, the microcontroller chip should first be selected to include the required types; if the chip does not contain the necessary I/O methods or devices, then a chip with as many I/O functions as possible that meets the requirements should be selected, and additional peripheral circuits should be used to meet the design requirements.
It is best not to select chips that exceed the design requirements significantly, as this may lead to unnecessary economic costs.
From a technical perspective, how should the CPU of a microcontroller be selected?
Answer: The key to selection lies in whether the microcontroller’s CPU has suitable throughput.
The CPU throughput of a microcontroller relates to its ability to process information and execute control tasks. If a microcontroller with excessive processing capability is selected, it wastes resources; conversely, if the processing capability is insufficient, it will not function properly.
From a technical perspective, in what aspects is the processing capability of a microcontroller reflected?
Answer: The processing capability of a microcontroller is mainly reflected in: CPU operating speed, instruction functionality, instruction cycle duration, interrupt capability, stack size, etc.
From a technical perspective, what are the extreme performance characteristics of microcontrollers?
Answer: Microcontrollers have specific application environments, so each model has extreme performance indicators. The extreme performance of microcontrollers generally includes: maximum operating temperature, minimum operating temperature, maximum operating voltage, minimum operating voltage, maximum power consumption, maximum current, etc.
From a practical perspective, what aspects does the practicality of microcontrollers include?
Answer: The practicality of microcontrollers includes: purchasing channels for chips, supply volume, production volume, and trends in updates and replacements.
What stages does a microcontroller application system generally go through from preparation to operation?
Answer: The implementation of a microcontroller application system generally involves several stages: demand research for the control object, selection of control schemes, overall conception, hardware design, software design, board production, component installation, program compilation, software and hardware simulation debugging, solidifying application programs, microcomputer operation, and overall debugging.
Why is it necessary to use development tools during the debugging process of a microcontroller?
Answer: The microcontroller application system must go through a debugging phase; only through debugging can problems be identified, errors corrected, and ultimately applications achieved. However, since the microcontroller cannot be controlled manually during program execution, it is necessary to use some development tools to allow debugging personnel to grasp and control it, observe the program’s operation process without altering existing data, performance, and results, and simulate real debugging on-site.
What characteristics should a microcontroller online simulator have to be considered complete?
Answer: (1) It should not occupy any resources of the microcontroller;
(2) It should provide users with sufficient simulation RAM space starting from address zero for use as the data storage of the user’s program memory;
(3) For user programs in simulation RAM or prototype EPROM, as well as interrupt control instructions and interrupt service programs, it should allow single-step, breakpoint, full-speed breakpoint, and continuous operation modes;
(4) It should have comprehensive software development tools, including:
Equipped with cross-assembly software to generate executable target files from user-written assembly language applications;
Having a rich library of subroutines that, during assembly, compiles along with user-designed programs into target programs, loaded into simulation RAM for debugging and solidification;
Having a high-level language compilation system that allows users to program conveniently in these high-level languages;
Having disassembly functions that can print or save the results of disassembling target programs.
What types of microcontroller development systems are there?
Answer: Microcontroller development systems can be divided into four categories: general-purpose development systems, practical development systems, general machine development systems, and simulation development systems.
What is the basic configuration of a general-purpose microcontroller development system?
Answer: A general-purpose microcontroller development system is equipped with an EPROM read/write device, simulation plug, and other peripherals as its basic configuration.
What are the characteristics of practical development systems?
Answer: The characteristics of practical microcontroller development systems are that the hardware of the development system is configured according to typical application systems of microcontrollers, and the system is equipped with monitoring programs and has self-development capabilities.
What are the advantages and disadvantages of practical microcontroller development systems?
Answer: The advantages are: it reduces the hardware workload during system development, shortens the development cycle, improves development efficiency, and has secondary development capabilities. The disadvantages are: when not optimally configured, there is significant waste of software and hardware resources, and the application scenarios are also limited.
What is a general machine development system?
Answer: A development system that adds a development template to a general-purpose computer is called a general machine development system.
What components make up the development template in a general machine development system? How is it used?
Answer: The hardware structure of the development template includes irreplaceable parts of the computer, such as the EPROM writing system, simulation head, and the microcontroller system necessary for CPU simulation. The development template can be inserted into the computer’s expansion slot or connected externally via a bus.
What are the advantages of a general machine development system?
Answer: Its advantages include the ability to fully utilize the software and hardware resources of the computer, leading to high development efficiency.
What is a simulation development system?
Answer: Generally, a system composed of a computer and simulation development software that relies entirely on software means for development is called a simulation development system.
What is the working principle of a simulation development system?
Answer: Its working principle is to use simulation development software on a computer to achieve hardware simulation, instruction simulation, and operational state simulation of the microcontroller, thus completing the entire process of application software development.
What are the advantages and disadvantages of simulation development systems?
Taking the SIM8051 simulation development system as an example, its simulation debugging functions are strong, efficient, and cost-effective. The simulation development system generally includes online simulator functions such as single-step, tracking, checking, and modifying, and can also simulate various interrupts and I/O response processes. Users only need to equip simulation/debugging software to turn their microcomputer into a general-purpose simulation development system. Its disadvantage is that it cannot diagnose hardware systems or perform timely simulations.
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