The 8031/8051/8751 is an early product of Intel Corporation.
1, the characteristics of 8031
The 8031 ​​does not have a program memory ROM. When used, the user needs to connect an external program memory and a logic circuit 373. The external program memory is mostly the 2764 series of EPROM. If the user wants to modify the program written to the EPROM, he must first wipe it with a special UV lamp and then write it. There is no confidentiality in the program code written to the add-in memory.
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2, the characteristics of 8051
There are 4k ROM in the 8051 chip, no need for external external memory and 373, which can better reflect the "single piece" concise. But the program you edited can't be written into its ROM. Only the program is sent to the chip factory for you to write it, and it is a one-off. You and the chip factory can't rewrite its contents in the future.
3, the characteristics of 8751
The 8751 is basically the same as the 8051, but there are 4k EPROMs in the 8751. Users can write their own programs into the EPROM of the MCU for field experiments and applications. The EPROM rewrite also needs to be irradiated with UV light for a certain period of time and then burned. write.
Due to the early application of the above types of single-chip microcomputers, the impact has become very large and has become the de facto industry standard. Later, many chip manufacturers cooperated with Intel in various ways, and also introduced the same type of single-chip microcomputer. Like many versions of a single-chip microcomputer, although the manufacturing process is constantly changing, the kernel is the same, that is to say, this type The MCU instruction system is fully compatible, and most of the pins are also compatible; they can be directly interchanged in use. People collectively refer to these same single-chip microcomputers as the "51 series single-chip microcomputer", and learn one of them, then all 51 series.
4, AT89C51, AT89S51 features
Among the many 51 series MCUs, it is more practical to use ATMEL's AT89C51 and AT89S51, because it is not only fully compatible with 8051 instructions and pins, but also its on-chip 4K program memory is FLASH process. It can be erased and rewritten instantaneously by means of electricity. These functions are generally available to programmers specially designed for ATMEL AT89xx. Obviously, this kind of single-chip computer has low requirements for development equipment and the development time is also greatly shortened. Programs written into the microcontroller can also be encrypted, which in turn protects your work. Then, the current price of AT89C51 and AT89S51 is lower than that of the 8031, and the market supply is also sufficient.
The AT89S51 and 52 are new models introduced by ATMEL in 2003. In addition to being fully compatible with the 8051, there are more ISP programming and watchdog functions. We also designed a programming, learning, and experiment board specifically for this new film.
5, AT89C2051, AT89C1051 and other characteristics
ATMEL's 51 series also has AT89C2051, AT89C1051 and other varieties, these chips are based on the AT89C51 based on some features to streamline the formation of a streamlined version. AT89C2051 removed the P0 port and P2 port, the internal program FLASH memory is also as small as 2K, the package form is also changed from 51 P40 foot to 20 feet, the corresponding price is also lower, especially suitable for some smart toys, handheld instruments, etc. The program is not used in the circuit environment; AT89C1051 on the basis of 2051, once again streamlined the serial port function, etc., the program memory is reduced to 1k again, of course, the price is lower.
For 2051 and 1051, although some resources have been lost, they have integrated a precision comparator on the chip. Don't underestimate this small comparator. It provides great convenience for us to measure some analog signals. With the addition of several resistors and capacitors, we can measure the amount of voltage, temperature, etc. we need daily. This is a valuable resource for the design of many household appliances.
ATMEL's 51, 2051, and 1051 are available in a variety of packages, such as the AT89C(S)51 with PDIP, PLCC, and PQFP/TQFP packages; the 2051/1051 has PDIP and SOIC packages. The figure below is a partial package of the object.
Since the cores of the 51 series MCUs are the same, the books of the Intel MCS 8051 MCU are still used in the 51 MCU teaching materials. The development software and tools are the same. We collectively refer to the 8051 development system, environment, and so on. For example, the assembler ASM51, Keil C51, MedWin, etc. introduced on our website are all development software for the 8051 core microcontroller.
Single pair AT89C51, AT89S51, in the actual circuit can be directly interchanged 8051\\8751, replace 8031 ​​is only the 31st foot is different, 8031 ​​because there is no internal ROM, 31 feet need to be grounded (GND), the microcontroller will be after the start The external program memory reads the instruction; while the 8051/8751/89c51 has a program memory internally, the 31 pin is connected to the high level (VCC), and the instruction is directly read internally after the microcontroller is started. That is, the 31 pin of the 51 chip controls whether the single-chip program reads from the internal or external, the 31-pin is connected to the power supply, the program reads from the inside, the 31-pin is grounded, and the program is read from the outside. No other changes are required. In addition, after replacing 8031 ​​with AT89C51 and AT89s51, since there is no need for external memory, it is not necessary to install the external memory of the original circuit and the 373 chip.
6, the difference between 89S51 and 89C51
MCS-51 MCU is a product launched by INTE in the United States in 1980. The typical product is 8031 ​​(there is no program memory inside, the actual use has been eliminated by the market), 8051 (chip adopts HMOS, the power consumption is 630mW, which is 5 times that of 89C51). , the actual use has been eliminated by the market) and 8751 and other general-purpose products, until now, MCS-51 core series compatible microcontroller is still the mainstream application of applications (such as the current popular 89S51, 89C51, etc.), colleges and professional schools The training materials are still based on the theoretical basis of the MCS-51 microcontroller. Some documents even refer to the MCS-51 series of single-chip microcomputers. The 8051 is the most typical representative of the early days. The MCS-51 core has actually become the standard of an 8-bit microcontroller.
Other companies' 51 MCU products are compatible with the MCS-51 core. The same piece of program, the results run on the hardware of each microcontroller manufacturer are the same, such as ATMEL 89C51 (has been discontinued), 89S51, PHILIPS (Philips), and WINBOND (Huabang), etc., we often say The discontinued 89C51 refers to ATMEL's AT89C51 single-chip microcomputer. At the same time, it has enhanced many features, such as clocks. It is better to use Flash (the program memory can be rewritten at least 1000 times). The memory is taken with the original ROM. (Write once), the performance of the AT89C51 is already very good compared to the 8051.
However, in terms of marketization, the 89C51 has been challenged by the PIC microcontroller camp. The most fatal flaw of the 89C51 is that it does not support the ISP (Online Update Program) function. It must add new features such as the ISP function to better extend the legend of the MCS-51. 89S51 is to replace 89C51 in this background. Now, 89S51 has become a new darling in the practical application market. Atmel, which is the market share first, has discontinued AT89C51 and will replace it with AT89S51. The 89S51 has been improved in terms of technology. The 89S51 uses a new 0.35 process, which reduces costs and increases functionality and competitiveness. The 89SXX can be compatible with 51 series chips such as 89CXX. At the same time, Atmel no longer accepts orders from 89CXX. The 89C51 that everyone sees on the market is actually a huge inventory of Atmel's pre-production. If the market needs it, Atmel can of course resume production of the AT89C51.
7, 89S51 new features added to the 89C51 include:
1) The performance has been greatly improved, the price is basically unchanged, even lower than the 89C51!
2) ISP online programming function, the advantage of this function is that the program in the MCU memory does not need to be stripped from the working environment. It is a powerful and easy to use feature.
3) The maximum operating frequency is 33MHz. Everyone knows that the extreme working frequency of the 89C51 is 24M, which means that the S51 has a higher operating frequency and thus has a faster calculation speed.
4) Has a duplex UART serial channel.
5) The internal integrated watchdog timer eliminates the need for an external watchdog timer unit circuit like the 89C51.
6) Double data indicator.
7) Power off indicator.
8) A new encryption algorithm, which makes the ** of the 89S51 impossible, and the confidentiality of the program is greatly enhanced, so that the intellectual property can be effectively protected from being invaded.
9) Compatibility: Fully compatible with 51 full-word series products. For example, 8051, 89C51 and other early MCS-51 compatible products.
Compared with S51, C51 is inferior, and the advancement of technology in the practical application market is always forward.
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PIC series microcontroller
The PIC microcontroller series introduced by Microchip Corporation of the United States first adopts the embedded microcontroller of RISC structure. Its high speed, low voltage, low power consumption, high current LCD driving capability and low-cost OTP technology all reflect the microcontroller industry. New trend.
Now PIC series single-chip microcomputer has risen year by year in the world single-chip market share ranking, especially in the 8-bit single-chip market, it is said to have risen from the 20th place in 1990 to the current second place. PIC microcontrollers have come out of the coverage market, and there are three (also known as three-level) series of various models of products, so you can see PIC microcontrollers from computer peripherals, home appliance control, telecommunications, smart instruments, automotive electronics. Widely used in various fields of financial electronics. Today's PIC microcontrollers are already one of the most influential embedded microcontrollers in the world.
1 PIC 8-bit microcontroller classification
There are three series of PIC 8-bit microcontroller products, namely basic, intermediate and advanced.
a Basic Series This class features low price, such as PIC16C5X, which is suitable for a variety of cost-sensitive home appliances. Another example is the PIC12C5XX, the world's first 8-pin low-cost single-chip microcomputer. Because of its small size, it can be used in the space of home appliances that could not be used before.
b Intermediate Series This class is the most versatile series of PIC. It has been improved on basic products and maintains high compatibility. The external structure is also available in a variety of packages from 8-pin to 68-pin, such as the PIC12C6XX. This class of products has high performance, such as internal A / D converter, E2PROM data memory, comparator output, PWM output, I2C and SPI interfaces. The PIC mid-range range is suitable for the design of a wide range of high, medium and low gear electronics.
c Advanced Series This series of products, such as PIC17CXX, is characterized by high speed, so it is suitable for high-speed digital computing applications, and it can complete 8&TImes; 8 (bit) binary multiplication capability in one instruction cycle (160 ns), so Can replace some DSP products. In addition, PIC17CXX has rich I/O control functions, and can be extended with EPROM and RAM, making it one of the highest performance models in 8-bit MCUs. Therefore, it is very suitable for use in high and mid-range electronic equipment.
The above three-level (level) PIC 8-bit microcontrollers also have high code compatibility, making it easy for users to convert code from one model to another. The PIC 8-bit MCU has the advantages of less instructions and faster execution. The main reason is that the PIC series MCUs are different in structure from other MCUs. This series of single-chip microcomputers introduces a dual-bus and two-stage instruction pipeline structure originally used for small computers. This structure is structurally different from a microcontroller that generally uses a CISC (Complex Instruction Set Computer).
Dual bus structure
A single-chip microcomputer with a CISC structure fetches instructions and data in the same memory space, and there is only one bus in the chip. This bus has both instructions and data to be transferred (as shown in Figure 1-a). Therefore, it is not possible to access both program memory and data memory at the same time. Because there is only one kind of bus directly connected to the CPU, it is required to pass data and instructions at the same time. Obviously, it is a "bottleneck". The data and instructions in the bottle are poured out together, and the bottleneck is often stuck. Therefore, a single-chip microcomputer having such a structure can only take out an instruction first, and then execute the instruction (in the process, it is often necessary to take a number), and then, after the execution of the instruction is completed, another instruction is taken out, and the next one is continued. This structure is often called Feng? The Neumann structure, also known as the Princeton structure.
Here PIC series MCU uses a dual bus structure, the so-called Harvard structure. This structure has two types of buses, a program bus and a data bus. These two buses can use different word lengths. For example, the PIC series MCU is an eight-bit machine, so its data bus is of course eight bits. However, the low-end, mid-range, and high-end PIC series machines have 12-bit, 14-bit, and 16-bit instruction buses, respectively. In this way, when the instruction is fetched, the instruction bus is used, and when the data is fetched, the data bus does not conflict with each other.
Two-stage instruction pipeline structure
Since the PIC series microcontrollers use a Harvard architecture with separate instruction space and data space, two buses with different numbers of bits are used. Therefore, it is possible to fetch and fetch data at the same time, so the fetch and execute instructions in the PIC family of microcontrollers use the instruction pipeline structure. When the first instruction is fetched, it enters the execution phase. At this time, it may be taken from one register and sent to another register, or transferred from a port to a register, but the data does not flow through the program bus. It only flows in the data bus, so during this time, the program bus is empty and the second instruction can be fetched at the same time. When the first instruction is executed, the second instruction can be executed, and the third instruction can be taken out, ... and so on. Thus, in addition to the fetching of the first instruction, the execution of the remaining instructions and the fetching of the next instruction are performed simultaneously, so that the highest efficiency can be obtained in each clock cycle.
In most microcontrollers, fetch and instruction execution are sequential, but in the PIC microcontroller instruction pipeline structure, fetch and execute instructions overlap in time, so PIC series MCUs can achieve single cycle. instruction.
Only two cycles are required for program branch instructions (such as GOTO, CALL) that involve changing the PC value of the program counter.
In addition, the structural characteristics of the PIC are also reflected in the register set. For example, the register I/O port, timer and program register are all in the form of RAM structure, and only one cycle is required to complete the access and operation. Other microcontrollers often require two or more cycles to change the contents of the register. The above items are the important reasons why the PIC series MCU can achieve a small number of instructions and most of them are single-cycle instructions.
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AVR series MCU
The AVR MCU is an enhanced RISC (Reduced InstrucTIon Set CPU) RISC high-speed 8-bit MCU developed by ATMEL in 1997. AVR's single-chip microcomputer can be widely used in computer external equipment, industrial real-time control, instrumentation, communication equipment, household appliances and other fields.
1 AVR microcontroller advantages and features
a AVR microcontroller is easy to start, easy to upgrade, and low cost. The beginner of the MCU only needs an ISP download line, and the software program that is edited and debugged is directly written into the AVR MCU, which can develop various packaged devices in the AVR MCU series. AVR microcontrollers are therefore known in the industry as "the first line of the world." The AVR program is written directly on the board for program modification, burning, etc., which is convenient for product upgrades. AVR MCU can use ISP to download the programming mode online (that is, write the program compiled on the PC to the program memory of the MCU), and you can perform all AVR MCU without purchasing emulator, programmer, wiper and chip adapter. Development applications, which can save a lot of development costs. The program memory can be erased up to 10,000 times without scrapping.
b High speed, low consumption and confidentiality. First, the AVR MCU is a high-speed embedded MCU: The AVR MCU has a prefetch instruction function, that is, when an instruction is executed, the next instruction is fetched in advance, so that the instruction can be executed in one clock cycle. Multi-accumulator type, data processing speed. The AVR microcontroller has 32 general-purpose working registers, which is equivalent to 32 overpasses and can be quickly passed. Interrupt response is fast. The AVR microcontroller has multiple fixed interrupt vector entry addresses for fast response to interrupts. AVR microcontrollers consume low energy. For typical power consumption, the WDT is 100nA when turned off, making it ideal for battery-powered applications. Some devices can work with a minimum of 1.8 V. AVR microcontroller has good security performance. It has an unbreakable bit-locked lock Bit technology, and the security bit unit is hidden inside the chip and cannot be seen with an electron microscope.
c I / O port is powerful, with A / D conversion and other circuits. The I/O port of the AVR MCU is a true I/O port that correctly reflects the true I/O port input/output. Industrial grade products with high current (sink current) 10mA ~ 40mA, can directly drive thyristor SSR or relay, saving peripheral drive devices. The AVR microcontroller has an analog comparator, and the I/O port can be used as an A/D converter to form an inexpensive A/D converter. Devices such as the ATmega48/8/16 have eight 10-bit A/Ds. Some AVR single-chip microcomputers can form a single-chip microcomputer system with zero peripheral components, so that the single-chip microcomputer can work without additional components, which is simple and convenient, and has low cost. The AVR microcontroller can reset the startup reset to improve the reliability of the microcontroller. The watchdog timer implements safety protection to prevent the program from being chaotic (flying) and improve the anti-interference ability of the product.
d has powerful timer/counter and communication interface. The Timer/Event Counter T/C has 8 bits and 16 bits and can be used as a comparator. The counter external interrupt and PWM (also used as D/A) are used to control the output. Some models of AVR microcontrollers have 3 to 4 PWMs, which is an ideal device for stepless speed regulation of the motor. The AVR MCU has a serial asynchronous communication UART interface, which does not occupy the timer and SPI synchronous transmission function. Because of its high speed characteristics, it can work under the standard standard integer frequency, and the baud rate can reach 576K.
2 AVR 8-Bit MCU's biggest features
Compared with other 8-Bit MCUs, the biggest features of the AVR 8-Bit MCU are:
? Harvard architecture with 1MIPS / MHz high-speed processing capability;
? The Super Function Reduced Instruction Set (RISC), with 32 general purpose working registers, overcomes bottlenecks caused by the 8051 MCU processing with a single ACC;
? Fast access register group and single-cycle instruction system greatly optimize the size and execution efficiency of the target code. Some models have very large FLASH, which is especially suitable for development using high-level languages.
? The output is the same as the HI's HI/LOW, which can output 40mA (single output). It can be set as a three-state high-impedance input or a pull-up resistor input for input, and has the capability of sinking current of 10mA-20mA.
? On-chip integration of multiple frequency RC oscillator, power-on automatic reset, watchdog, start delay and other functions, the peripheral circuit is simpler, the system is more stable and reliable;
? Most AVRs are rich in resources: E2PROM, PWM, RTC, SPI, UART, TWI, ISP, AD, Analog Comparator, WDT, etc.
? In addition to the ISP function, most AVRs also have an IAP function to facilitate upgrading or destroying applications.
(3) 16-BIT microcontroller
The 16-bit microcontroller was developed after 1983. The characteristics of this type of MCU are: CPU is 16-bit, the operation speed is generally higher than 8-bit machine, and some MCUs have an addressability of up to 1MB. The chip contains A/D and D/A conversion circuits and supports high-level languages. These types of microcontrollers are mainly used for process control, smart meters, household appliances, and controllers as external devices for computers. Typical products include Intel's MCS-96/98 series, Motorola's M68HC16 series, NS's 783&TImes; &TImes; series, TI's MSP430 series, and more.
Among them, the MSP430 series is the most prominent. It uses a reduced instruction set (RISC) architecture with rich addressing modes (7 source operand addressing, 4 destination operand addressing), a compact 27 core instructions, and a large number of analog instructions; a large number of registers As well as on-chip data memory can participate in a variety of operations; there are efficient table lookup processing instructions; higher processing speed, the instruction cycle is 125 ns under 8MHz crystal drive. These features ensure that highly efficient source programs can be programmed.
In terms of computing speed, the MSP430 series of microcontrollers can achieve a 125ns instruction cycle driven by an 8MHz crystal. A 16-bit data width, 125ns instruction cycle, and a versatile hardware multiplier (which enables multiply-accumulate) can implement some algorithms for digital signal processing (such as FFT).
MSP430 series MCUs have many interrupt sources and can be nested arbitrarily, which is flexible and convenient to use. When the system is in a power-saving standby state, wake it up with an interrupt request using only 6us.
The ultra-low-power MSP430 microcontroller has ultra-low power consumption because of its uniqueness in reducing the chip's power supply voltage and its flexible and controllable operating clock.
First, the power supply voltage of the MSP430 series MCU is 1.8~3.6V. Therefore, when the clock is running at 1MHz, the current of the chip will be around 200~400uA, and the minimum power consumption of the clock off mode is only 0.1uA.
Second, the unique clock system design. There are two different system clock systems in the MSP430 family: the basic clock system and the frequency-locked loop (FLL and FLL+) clock system or the DCO digital oscillator clock system. Some use a crystal oscillator (32768Hz), and some use two crystal oscillators). The clock required by the CPU and functions is generated by the system clock system. And these clocks can be turned on and off under the control of the instructions to achieve control of the overall power consumption.
Since the functional modules that are turned on during system operation are different, that is, different operating modes are used, the power consumption of the chips is significantly different. There is one active mode (AM) and five low power modes (LPM0~LPM4) in the system. In the standby mode, the power consumption is 0.7uA, and in the power-saving mode, the minimum is 0.1uA.
After the system works stably after power-on reset, the CPU is first started by DCOCLK to ensure that the program starts from the correct position to ensure sufficient oscillation and stabilization time of the crystal oscillator. The software can then set the control bits of the appropriate registers to determine the final system clock frequency. If the crystal oscillator fails when used as the CPU clock MCLK, the DCO will automatically start to ensure that the system works properly; if the program runs away, it can be reset by the watchdog.
A wide range of on-chip peripheral modules MSP430 series microcontrollers integrate a wide range of on-chip peripherals. They are Watchdog (WDT), Analog Comparator A, Timer A (Timer_A), Timer B (Timer_B), Serial 0, 1 (USART0, 1), Hardware Multiplier, LCD Driver, 10 Bit/12 Different combinations of bit ADC, I 2 C bus direct data access (DMA), port O (P0), ports 1~6 (P1~P6), basic timer (Basic Timer). Among them, the watchdog can quickly reset the program when it is out of control; the analog comparator compares the analog voltage, and the timer can be used to design the A/D converter; the 16-bit timer (Timer_A and Timer_B) has the capture/compare function. A large number of capture/compare registers can be used for event counting, timing generation, PWM, etc. Some devices have applications that can realize asynchronous, synchronous and multiple access serial communication interfaces to facilitate multi-machine communication and other applications; I/O port, up to 6*8 I/O lines; P0, P1, P2 ports can receive external rising or falling edge interrupt inputs; 12/14-bit hardware A/D converters have higher conversion Rate up to 200kbps for most data acquisition applications; direct drive of up to 160 segments of liquid crystal; 2-way 12-bit D/A conversion; hardware I 2 C serial bus interface for memory serial expansion; In order to increase the data transmission speed, a direct data transmission (DMA) module is adopted. These on-chip peripherals of the MSP430 family of microcontrollers provide great convenience for the system's single-chip solution.
Convenient and efficient development environment Currently, the MSP430 series has three types of devices: OPT type, FLASH type and ROM type. These devices are developed in different ways. For OPT type and ROM type devices, the device is programmed or masked after successful development using the emulator; for the FLASH type, there is a very convenient development and debugging environment, because the device has a JTAG debug interface, and there is an erasable write The FLASH memory is therefore developed by first downloading the program into the FLASH and then running the software control program in the device through the JTAG interface to read the on-chip information for the designer to debug. This method requires only one PC and one JTAG debugger, without the need for an emulator and programmer. The development languages ​​are assembly language and C language.
The MSP430 MCU is mainly based on the FLASH type.
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16-BIT microcontroller
The 16-bit microcontroller was developed after 1983. The characteristics of this type of MCU are: CPU is 16-bit, the operation speed is generally higher than 8-bit machine, and some MCUs have an addressability of up to 1MB. The chip contains A/D and D/A conversion circuits and supports high-level languages. These types of microcontrollers are mainly used for process control, smart meters, household appliances, and controllers as external devices for computers. Typical products include Intel's MCS-96/98 series, Motorola's M68HC16 series, NS's 783×× series, and TI's MSP430 series.
Among them, the MSP430 series is the most prominent. It uses a reduced instruction set (RISC) architecture with rich addressing modes (7 source operand addressing, 4 destination operand addressing), a compact 27 core instructions, and a large number of analog instructions; a large number of registers As well as on-chip data memory can participate in a variety of operations; there are efficient table lookup processing instructions; higher processing speed, the instruction cycle is 125 ns under 8MHz crystal drive. These features ensure that highly efficient source programs can be programmed.
In terms of computing speed, the MSP430 series of microcontrollers can achieve a 125ns instruction cycle driven by an 8MHz crystal. A 16-bit data width, 125ns instruction cycle, and a versatile hardware multiplier (which enables multiply-accumulate) can implement some algorithms for digital signal processing (such as FFT).
MSP430 series MCUs have many interrupt sources and can be nested arbitrarily, which is flexible and convenient to use. When the system is in a power-saving standby state, wake it up with an interrupt request using only 6us.
The ultra-low-power MSP430 microcontroller has ultra-low power consumption because of its uniqueness in reducing the chip's power supply voltage and its flexible and controllable operating clock.
First, the power supply voltage of the MSP430 series MCU is 1.8~3.6V. Therefore, when the clock is running at 1MHz, the current of the chip will be around 200~400uA, and the minimum power consumption of the clock off mode is only 0.1uA.
Second, the unique clock system design. There are two different system clock systems in the MSP430 family: the basic clock system and the frequency-locked loop (FLL and FLL+) clock system or the DCO digital oscillator clock system. Some use a crystal oscillator (32768Hz), and some use two crystal oscillators). The clock required by the CPU and functions is generated by the system clock system. And these clocks can be turned on and off under the control of the instructions to achieve control of the overall power consumption.
Since the functional modules that are turned on during system operation are different, that is, different operating modes are used, the power consumption of the chips is significantly different. There is one active mode (AM) and five low power modes (LPM0~LPM4) in the system. In the standby mode, the power consumption is 0.7uA, and in the power-saving mode, the minimum is 0.1uA.
After the system works stably after power-on reset, the CPU is first started by DCOCLK to ensure that the program starts from the correct position to ensure sufficient oscillation and stabilization time of the crystal oscillator. The software can then set the control bits of the appropriate registers to determine the final system clock frequency. If the crystal oscillator fails when used as the CPU clock MCLK, the DCO will automatically start to ensure that the system works properly; if the program runs away, it can be reset by the watchdog.
A wide range of on-chip peripheral modules MSP430 series microcontrollers integrate a wide range of on-chip peripherals. They are Watchdog (WDT), Analog Comparator A, Timer A (Timer_A), Timer B (Timer_B), Serial 0, 1 (USART0, 1), Hardware Multiplier, LCD Driver, 10 Bit/12 Different combinations of bit ADC, I 2 C bus direct data access (DMA), port O (P0), ports 1~6 (P1~P6), basic timer (Basic Timer). Among them, the watchdog can quickly reset the program when it is out of control; the analog comparator compares the analog voltage, and the timer can be used to design the A/D converter; the 16-bit timer (Timer_A and Timer_B) has the capture/compare function. A large number of capture/compare registers can be used for event counting, timing generation, PWM, etc. Some devices have applications that can realize asynchronous, synchronous and multiple access serial communication interfaces to facilitate multi-machine communication and other applications; I/O port, up to 6*8 I/O lines; P0, P1, P2 ports can receive external rising or falling edge interrupt inputs; 12/14-bit hardware A/D converters have higher conversion Rate up to 200kbps for most data acquisition applications; direct drive of up to 160 segments of liquid crystal; 2-way 12-bit D/A conversion; hardware I 2 C serial bus interface for memory serial expansion; In order to increase the data transmission speed, a direct data transmission (DMA) module is adopted. These on-chip peripherals of the MSP430 family of microcontrollers provide great convenience for the system's single-chip solution.
Convenient and efficient development environment Currently, the MSP430 series has three types of devices: OPT type, FLASH type and ROM type. These devices are developed in different ways. For OPT type and ROM type devices, the device is programmed or masked after successful development using the emulator; for the FLASH type, there is a very convenient development and debugging environment, because the device has a JTAG debug interface, and there is an erasable write The FLASH memory is therefore developed by first downloading the program into the FLASH and then running the software control program in the device through the JTAG interface to read the on-chip information for the designer to debug. This method requires only one PC and one JTAG debugger, without the need for an emulator and programmer. The development languages ​​are assembly language and C language.
The MSP430 MCU is mainly based on the FLASH type.
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32-BIT microcontroller
The 32-bit microcontroller has a 32-bit word length and is a top-of-the-line microcontroller with extremely high computational speed. In recent years, with the new development of home electronic systems, the market prospects of 32-bit microcontrollers are promising.
Shortly after the emergence of 16-bit microcontrollers, several major companies have introduced 32-bit single-chip microcomputer series that represent the highest performance and technology level. The 32-bit MCU has a very high level of integration. The internal RISC (Reduced Instruction System Computer) structure is adopted. The CPU can be compatible with other microcontrollers. The main frequency can be up to 33MHz. The instruction system is further optimized and the operation speed can be dynamically changed. With a high-level language compiler, powerful interrupt control system, timing / event control system, synchronous / asynchronous communication control system. Representative products include Intel's MCS-80960 series, Motorola's M68300 series, Hitachi's Super H (short for SH) series, and so on.
These types of microcontrollers are mainly used in automotive, aerospace, advanced robots, military equipment and other aspects. It represents the difference and characteristics of 51, PIC, AVR, 16, 32-BIT series MCU
The high and new technology level in the development of single chip microcomputer.
ARM's mainstream position in 32-bit MCUs is unquestionable. ARM was founded in 1991 in Cambridge, England, and is primarily licensed to sell chip design technology. At present, the ARM technology intelligent property (IP) core processor, which we call the ARM processor, has been used in various product markets such as industrial control, consumer electronics, communication systems, network systems, and wireless systems. The processor application of ARM technology accounts for more than 75% of the market of 32-bit RISC microprocessors. ARM technology not only gradually penetrates into all aspects of our lives, we can even say that ARM is not in the human living environment. A missing link.
At present, the common ARM processor architecture on the market can be divided into ARM7, ARM9 and ARM11. The newly launched Cortex series is still under development and verification, and there are no related products on the market. ARM is also the first vendor to introduce a multi-core architecture in embedded processors.
ARM's first multi-core architecture is ARM11 MPCore, which is built on top of the original ARM11 processor core. The ARM11 core was released in October 2002. In order to further improve the performance, the pipeline length is extended to 8th order, and the processing unit is added to prefetch, decode, send, convert/MAC1, execute/MAC2, memory access/MAC3 and Write eight units, etc., which belongs to the ARM V6 instruction set architecture. The ARM11 uses the most advanced 0.13μm manufacturing process at the time, operating at frequencies up to 500 to 700MHz. If you use the 90nm process, the ARM11 core's operating frequency can easily reach more than 1GHz - for embedded processors, this is obviously quite amazing, but obviously 1GHz is not a balanced setting in the ARM11 system, so there is almost no The manufacturer introduced an ARM11 architecture processor up to 1GHz.
The logic core of ARM11 has also undergone a lot of improvements, the most important of which is "predictive function of static/dynamic combined conversion". The ARM11 execution unit contains a 64-bit, four-state address translation buffer that is used to store the most recently used translation address. When the dynamic conversion prediction mechanism is used and the correct address cannot be found in the addressing buffer, the static conversion prediction function will immediately take over its position. In the actual test, the accuracy of using dynamic prediction alone is 88%, and the accuracy of using static prediction mechanism is only 77%, while the static/dynamic prediction combination mechanism of ARM11 can achieve high accuracy of 92%. In response to the increased power consumption of high clock speeds, ARM11 uses an intelligent power management technology called "IEM (Intelligent Energy Manager)", which dynamically adjusts the voltage of the processor according to the task load, thereby effectively reducing Its own power consumption. This series of improvements allows the ARM11's power-performance ratio to continue to increase, averaging 0.6mW per MHz (0.8mW with cache), and the processor's maximum performance can reach 660 Dhrystone MIPS, far more than the previous generation. product.
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