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SCM also be known as micro-controller (Microcontroler), SCM only by the CPU chip, developed from a dedicated processor. The first design concept is by and large number of peripheral devices integrated in a CPU chip, the computer system is smaller, more easily integrated.
Early SCM are eight or the four. One of the most successful is the 8031 INTEL, because simple and reliable and good performance was praised. Since then in 8031 on the development of a series MCS51 SCM system. Based on this system until now the SCM system is still widely used. As the field of industrial control requirements of the increase, began to appear in 16-bit microcontrollers. As the 1990s after the big consumer electronics product development, SCM technology got a huge raise. With the emergence of INTEL i960 series, especially the later ARM wide range of applications, 32-bit microcontroller quickly replaced by 16 high-end MCU status and enter the mainstream market. And the traditional 8-bit microcontrollers performance has been improving rapidly, the capacity increase compared with the 1980s a few hundred times. At present, high-speed 32-bit microcontroller has exceeded 300 MHz, catching up performance of the mid-1990s, dedicated processors.
Contemporary SCM system is no longer only barebone environment in the development and use of a large number of dedicated embedded operating system is widely used in the SCM. As handheld computers and mobile phones with high-end microcontroller core can even direct the use of a dedicated Windows and Linux operating systems. SCM processor for more than suitable for embedded systems. In fact SCM is the world's largest number of computers. Modern human life used in almost every electronic and machinery products will integrate a microcontroller. Cell phone, telephone, calculator, household appliances, electronic toys, handheld computers and computer accessories such as a mouse with a 1-2 in both the Department of SCM. And personal computers will also have a large number of SCM at work. General vehicle equipped with more than 40 of the microcontroller, complex industrial control systems may have even hundreds of SCM at the same time work! SCM is not only far exceeded the number of PC and other integrated computing, or even than the number of human beings more. In SCM applications, the MCU anti-jamming system software debugging and MCU programming has been troubled for beginners. This article brief introduction of these two issues.
SCM system software interference methods
In improving the ability of anti-jamming system hardware, software interference with its flexible design, save hardware resources, more and more attention to reliability. Below the MCS-51 SCM system as an example, the computer system software interference methods for research.
In engineering practice, anti-jamming software on the content of the main ones being: 1, analog input signal to eliminate the noise (such as digital filter technology); two, is running the program when the chaos back to the right track approach. In this paper, which made several effective methods of anti-jamming software.
1. redundant directives
CPU process is to take instructions from operating code, and then take a few operators. When the PC interference errors, procedures will be from the normal track "flying", when flying to a double-byte instructions, if the instructions for a few moments landed on the operation, as the number-up operation operation code, procedural error will be . If the "fly" to the three-byte instructions, a greater probability of error.
In some key areas were inserted into single-byte instructions, or to be effective single-byte command rewrite directive known as redundancy. Is usually double-byte instructions and orders three bytes inserted after more than two bytes of the NOP. This flew to operate even if the number of flying procedures, the air operations of NOP because of the existence of the directive to avoid being behind the operation as a number of implementation, automatically into the right track.
In addition, the system flows to play an important role in the directive such as RET, RETI, LCALL, LJMP, JC, and other instructions inserted before the two NOP, also could be flying into the right track procedures to ensure that the implementation of these important directives.
2. interception technology
The so-called blocking, is flying the procedure will lead the specified location and then an error handling. Traps are usually software used to block flying procedures. Therefore must be reasonably designed trap, trap in the second to the appropriate location.
1) The design software trap
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