MOTOROLA J, K series low-cost microcontroller principles and applications

Author: Yu Yongquan / et al
Publisher:
Publish Date: 1998-12-01
Features: Introduction Microcontrollers are widely used in industries such as industrial control, automotive, instruments, household appliances, toys, computer peripherals, aerospace, transportation, and communications. Among various types of microcontrollers, low-cost microcontrollers are the most widely used. They are primarily used in products and scenarios with simple control tasks, small size, simple functions, and good cost-effectiveness, particularly effective in household appliances, toys, communication products, and certain instruments and equipment. The microcontrollers introduced in this book, the MOTOROLA J and K series, are the simplest in structure, have the fewest pins, and are inexpensive. The book explains the structural principles of these two series and provides various practical examples. This book is suitable for engineers and technicians involved in microcontroller applications and intelligent product development, as a reference for microcontroller control, household appliance or equipment design personnel, and as a textbook for relevant professional students. Excerpt: (4) Sound alarm; (5) Display, including LED and LCD displays; (6) A/D or D/A converters; (7) Other devices or functional components. If the application system includes the above devices or I/O methods, it is necessary to consider whether the microcontroller has circuit components that can meet these I/O methods or external devices. If the microcontroller does not contain the required electrical components or does not meet the required I/O methods, it cannot meet the system's needs. If the microcontroller has more components or I/O methods than needed, then the microcontroller exceeds the requirements. 3. Does the microcontroller's CPU have an appropriate throughput This is a question related to the computational capabilities of the microcontroller. For the needs of the application system, it must be carefully considered whether the microcontroller has sufficient processing power when performing control tasks for the system. If the microcontroller's processing power is too strong, it wastes the microcontroller's resources; if the processing power is insufficient, it cannot function normally. The processing power of the microcontroller is mainly reflected in the operating speed of the CPU, the functionality of the instructions, the length of the instruction cycle, interrupt capabilities, stack size, and other indicators. 4. Can the microcontroller's extreme performance meet the requirements An application system has a specific application environment, power consumption, and voltage conditions. The extreme performance of a microcontroller generally includes the highest operating temperature, the lowest operating temperature, the highest operating voltage, the lowest operating voltage, high power consumption, and high current, etc. For example, a microcontroller may have the following extreme parameters: - Highest temperature range: -55℃ to +125℃; - Highest voltage range: 2.7V to 6V; - Highest current: 150mA; - Highest power consumption: 1W. Clearly, it must be considered whether the application system's operating temperature is within the microcontroller's highest temperature range, and whether the operating voltage, current, and power consumption are within the microcontroller's extreme specifications. If not, the microcontroller cannot meet the needs of the application system. In this case, another microcontroller model that meets the application system's requirements should be selected.
II. Microcontroller Availability When a microcontroller is suitable for the application system, it is also necessary to consider the availability of this model. Availability includes the following points. 1. Can the microcontroller be purchased directly This refers to whether the microcontroller can be purchased directly from the manufacturer or its distributors. Whether the purchasing channels are smooth. 2. Does the microcontroller have sufficient supply as a product component Generally, microcontrollers are used as controllers in products, so the demand for microcontrollers is consistent with the number of products. At this time, it is required that enough microcontrollers can be purchased. Only in this way can the selected microcontroller meet the production needs of the product. 3. Is the microcontroller still in production When selecting a microcontroller, it should be chosen from models that are still in production. Microcontrollers that have been discontinued cannot be used because they have no subsequent supply capabilities, directly affecting the continued production and vitality of the product; at the same time, they also give a sense of obsolescence, thus affecting the novelty of the product. 4. Is the microcontroller being improved This mainly looks at whether a certain model of microcontroller has a new version introduced or is about to be introduced, which is beneficial for product upgrades and replacements. In other words, this microcontroller still has strong vitality and can be upgraded with new versions in a certain period, achieving twice the result with half the effort. Clearly, for microcontrollers that are about to be launched or have new versions, selecting them for application systems or products has strong potential.
III. Microcontroller Development Capability This is a very important factor. Whether the selected microcontroller has sufficient development tools directly affects whether the microcontroller can be developed smoothly and applied to the controlled object more quickly. If there are not enough development tools, the corresponding microcontroller model is not suitable for selection for relevant application systems. For the selected microcontroller, the following development tools should be considered. 1. Assembler 2. Compiler 3. Debugging tools (1) Evaluation Module (EVM); (2) In-circuit Emulator; (3) Logic Analyzer; (4) Debug Monitor; (5) Source-level Debug Monitor. 4. Online Demonstration Board Service (BBS) (1) Real-time Execution; (2) Application Examples; (3) Bug and Fault Reports; (4) Practical Software, including Free Assembler; (5) Sample Source Code. 5. Application Support (1) Consider whether there are dedicated application support organizations; (2) Consider whether there is support from application engineers, application technicians, or application sales personnel; (3) Consider the academic level of the support personnel and whether they are truly interested in solving related development issues; (4) Consider whether the support personnel and organizations have convenient communication tools and can receive support in a timely manner.
IV. Microcontroller Manufacturer History For microcontroller manufacturers, the following points should be primarily considered. (1) Evidence of competence in microcontroller design; (2) Advantages and reliability in production; (3) On-time delivery; (4) Long-term marketing performance; (5) Financial reports. Based on the above four principles for selecting microcontrollers, the most suitable microcontroller for the application system can be selected, ensuring that the application system has the highest reliability, the best performance-price ratio, the longest service life, and the best upgradeability.