PIC single chip microcomputer, as one of the work contents of many people, plays an important role. But most people do not know why to use PIC MCU. In order to solve this problem, we must start with several advantages of PIC MCU. Through this article on the advantages of PIC single chip microcomputer, I hope relevant people can have a certain grasp of PIC single chip microcomputer, and fully understand why to use PIC single chip microcomputer and the use scene.
Advantage 1: the biggest feature of PIC is that it does not engage in simple function accumulation, but starts from reality, pays attention to the performance and price ratio of products, and relies on the development of multiple models to meet the application requirements of different levels. In practice, different applications have different requirements for MCU functions and resources. For example, the igniter of a motorcycle needs a small single chip microcomputer with less I / O, little ram and program storage space and high reliability. If a 40 pin and powerful single chip microcomputer is used, the investment is large and it is inconvenient to use. Pic series has dozens of models from low to high, which can meet various needs. Among them, PIC12C508 single chip microcomputer has only 8 pins, which is the smallest single chip microcomputer in the world.
The model has 512 byte ROM, 25 byte ram, an 8-bit timer, an input line and 5 I / O lines. The market price is 3-6 yuan. Such a single chip microcomputer is undoubtedly very suitable for applications such as motorcycle igniters. The high-grade model of PIC, such as PIC16C74 (not yet the highest grade model), has 40 pins. Its internal resources are 4K ROM, 192 byte ram, 8-way A / D, 3 8-bit timers, 2 * modules, 3 serial ports, 1 parallel port, 11 interrupt sources and 33 I / O pins. Such a model can be comparable to the high-end models of other brands.
Advantage 2: streamlining instructions greatly improves its execution efficiency. Pic series 8-bit CMOS single chip microcomputer has a unique RISC structure. The Harvard bus structure with the separation of data bus and instruction bus makes the instruction have the characteristics of single word length, and allows the number of bits of instruction code to be more than 8 data bits. Compared with the traditional 8-bit single chip microcomputer with CISC structure, it can achieve 2:1 code compression and increase the speed by 4 times.
Advantage 3: zero time to market. Using PIC’s low-cost OTP chip can make the single chip microcomputer put the product on the market immediately after its application program is developed.
Advantage 4: pic has a superior development environment. The real-time performance of OTP single chip microcomputer development system is an important index. Like the ordinary 51 single chip microcomputer development system, most of them use high-grade models to simulate low-grade models, and the real-time performance is not ideal. Pic launches a new model and the corresponding simulation chip at the same time. All development systems are supported by special simulation chips, and the real-time performance is very good. From my personal experience, there is no case that the simulation results are different from the actual operation results.
Advantage 5: its pin has anti transient ability. It can be connected to 220V AC power supply through current limiting resistance, and can be directly connected to relay control circuit without optocoupler isolation, which brings great convenience to application.
Advantage 6: complete confidentiality. Pic uses a secret fuse to protect the code. After the user burns the code, the fuse will be blown, and others can no longer read it unless the fuse is restored. At present, PIC adopts fuse deep burial process, and the possibility of restoring fuse is very small.
Advantage 7: it has its own watchdog timer, which can be used to improve the reliability of program operation.
Advantage 8: sleep and low power mode. Although pic can not be compared with the new ti-msp430 in this regard, it can still meet the needs in most applications.