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Most people do not understand the knowledge points of this article "what are the advantages and disadvantages of single-chip microcomputer", so the editor summarizes the following contents, detailed contents, clear steps, and has a certain reference value. I hope you can get something after reading this article, let's take a look at this "what are the advantages and disadvantages of single-chip microcomputer" article.

Advantages and disadvantages of 51 single chip microcomputer

51 series is the most widely used single-chip microcomputer. due to the reasonable hardware structure, standard instruction system and "long production history", it has the advantage of preconception. Many famous chip companies in the world have purchased the core patented technology of 51 chip, and expanded its performance on the basis of it, so that the chip has been further improved and formed a huge system, which is still being renovated up to now. stir up the world of single-chip computers.

Excellent point one

One of the advantages of the 51 series is that it has a complete bitwise operating system from internal hardware to software, called bit processor, or Boolean processor.

Its processing object is not words or bytes but bits. It can not only deal with some bits of some special function registers in the chip, such as transmission, setting, zero clearing, testing, etc., but also carry out bit logic operation. Its function is very complete and easy to use. Although other kinds of single-chip computers also have the function of bit processing, it is rare to be able to perform bit logic operations.

Series 51 specially opens up a dual-function address range in the on-chip RAM area, 16 bytes, unit address 20H~2FH, which can be used for either byte processing or bit processing (128bits, corresponding bit address is OOH~7FH), which is extremely flexible to use. There is no doubt that this function provides great convenience to users. Because a more complex program will encounter many branches in the process of running, so many flag bits need to be established. In the process of running, the relevant flag bits need to be set, cleared or detected in order to determine the running direction of the program. To implement this process (including all the previous bit functions), you only need to use one bit operation instruction.

Advantage two

Another advantage of the 51 series is the multiplication and division instructions, which also brings convenience to programming. The division instruction of eight bits divided by eight bits has a quotient of eight digits, but the precision is not enough and it is not used much. And the multiplication instruction of eight bits multiplying eight bits, its product is sixteen bits, the precision can still meet the requirements, and it is used more. When multiplying, only one instruction is needed. Many eight-bit single-chip computers do not have the function of multiplication, and it is very inconvenient to make a subroutine call when multiplying.

Advantage three

The setting and use of the 51 series IWeiO pin is very simple, but the high power usually has no output capacity, which has both advantages and disadvantages. Therefore, other series of single-chip computers (such as PIC series, AVR series, etc.) have improved the I _ paw O port and added a direction register to determine the input or output, but the use has also become complicated.

Missing point

The original 51 series also has many aspects worth improving, such as running too slowly and so on. When the crystal frequency is 12MHz, the cycle of the machine reaches 1 μ s, which obviously can not meet the needs of modern high-speed operation.

Advantages and disadvantages of PIC single chip microcomputer

PIC single-chip microcomputer CPU adopts RISC structure, which has 33, 35 and 58 instructions respectively, depending on the level of single-chip microcomputer, and belongs to reduced instruction set. The 51 series has 111instructions and the AVR single chip microcomputer has 118instructions, all of which are more complex than the former.

Excellent point one

Using Haryard dual-bus structure, the running speed is fast, and the instruction cycle is about 160~200ns. It can make program memory access and data memory access parallel processing. This instruction pipeline structure completes two parts of work in one cycle, one is to execute the instruction, and the other is to fetch the next instruction from the program memory. Generally speaking, each instruction needs only one cycle (except individually), which is one of the reasons for efficient operation. In addition, it also has the characteristics of low working voltage, low power consumption, strong driving ability and so on.

Advantage two

The output circuit of PIC series MCU is CMOS complementary push-pull output circuit, which is bi-directional. The direction register used to set the input or output state is added to the 51 series Icano pin, which solves the problem that the 51 series Ithumb O pin is in the state of both input and output at high power level.

When setting 1 is the input state, and no matter whether the foot is high or low, it is in high resistance state; when setting 0, it is output state, no matter what level the foot is, it is low resistance state and has considerable driving ability, the low level suction current can reach 25mA, and the high level output current can reach 20mA.

Compared with the 51 series, this is a great advantage, it can directly drive the digital tube display and the external circuit is simple. Its Amax D is 10 bits, which can meet the precision requirement. It has the function of online debugging and programming.

Missing point

Unlike series 51, the special registers of this series of single-chip computers are not concentrated in a fixed address range (80~FFH), but are scattered in four address ranges, namely, Bank0:00-7FH, Bankl:80-FFH, Bank2:100-17FH and Bank3:180-1FFH. Only five special registers PCL, STATUS, FSR, PCLATH and INTCON appear in the four memory bodies at the same time.

In the process of programming, you have to deal with special registers, and you have to repeatedly select the corresponding memory bank, that is, to set or clear bits 6 (RPl) and 5 (RPO) of the status register STATUS. This brings some trouble to programming.

For the single-chip microcomputer mentioned above, its bit instruction operation is usually limited to the memory bank 0 interval (00~7FH). Data transmission and logical operations are basically carried out through the working register w (equivalent to 5l series accumulator A), and 51 series can also be transferred directly between registers (for example: MOV30H,20H; transmits the contents of register 20H directly to register 30H), so the bottleneck phenomenon of PIC single chip microcomputer is even more serious than 51 series, which is felt very much in programming.

Advantages and disadvantages of AVR single chip microcomputer

AVR single chip microcomputer is characterized by high performance, high speed and low power consumption. It cancels the machine cycle, takes the clock cycle as the instruction cycle, and carries out the flow operation. AVR MCU instructions are in word units, and most of the instructions are single-cycle instructions. In a single cycle, the function of this instruction can be executed and the next instruction can be read at the same time.

There are 32 general-purpose registers (RO-R31), and none of the first 16 registers (R0~R15) can directly deal with immediate numbers, so the versatility has decreased. In the 5l series, all of its general-purpose registers (address 00-7FH) can deal directly with immediate numbers, which is obviously better than the former.

Excellent point one

AVR series does not have the structure similar to accumulator A, it mainly realizes the function of A through R16~R31 register. In AVR, there is no data pointer DPTR like 5l series, but three 16-bit registers X (composed of R26, R27), Y (composed of R28\ R29) and z (composed of R30 and R31) complete the function of data pointer (equivalent to three sets of DPTR), and it can also run after increment or decrement.

In series 51, all logic operations must be performed in A, while AVR can be performed between any two registers, eliminating the hassle of going back and forth in A, which is better than 51 series.

Advantage two

The special register of AVR is concentrated in the address range of $00room3F, which does not need to go through the process of selecting memory like PIC, and is more convenient to use than PIC. The address ranges of AVR's on-chip RAM are $0060~$00DF (AT90S23131) and $0060 memory 025F (AT90S85l5, AT90S8535). They occupy the address of data space. These on-chip RAM are only used to store data and usually do not have the function of general register. When the program is complex, the general register R0-R31 appears to be insufficient, while the 51 series of general registers as many as 128s (4 times that of AVR) will not feel this way when programming.

Missing point

Like PIC, AVR has a direction register to control input or output. In the output state, the high-level output current is about 10mA, and the low-level suction current is 20mA. Not as good as PIC, but better than 51 series.

The above is about the content of this article on "what are the advantages and disadvantages of single-chip microcomputer". I believe we all have a certain understanding. I hope the content shared by the editor will be helpful to you. If you want to know more related knowledge, please pay attention to the industry information channel.

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