Explain the static clock method?

ATMEL51 microcontroller ATMEL 89 series 51 microcontroller features 1. Internal Flash memory is included Therefore, it can be very easy to carry out program modification during the development of the system, which greatly shortens the development cycle of the system. At the same time, in the process of system operation, can effectively save some data information, even if the external power supply damage does not affect the preservation of information.　　2. and 80C51 socket compatible 89 series microcontroller pin is the same as 80C51, so when the 89 series of microcontrollers to replace the 80C51, can be directly replaced. At this time, regardless of the use of 40-pin or 44-pin products, as long as the same pin 89 series microcontroller to replace the 80C51 microcontroller can be.　　3. Static clock 89 series microcontroller using a static clock, so you can save power, which is very useful for reducing the power consumption of portable products.　　4. Wrong programming and no scrap production General OTP products, once the wrong programming will become scrap. And 89 series microcontroller internal Flash memory, so, after the error programming can still be reprogrammed until the correct, so there is no scrap.　　5. Repeatable system test The system designed with 89 series microcontroller can be repeated system test; each test can be programmed into a different program, so as to ensure that the user's system design to reach the optimum. And with the user's needs and development, but also can be modified, so that the system can constantly follow the user's latest requirements.　　Internal structure of ATMEL 89 series 51 microcontroller 1. 8031CPU 2. oscillator circuit 3. bus control component 4. interrupt control component 5. on-chip Flash memory 6. on-chip RAM 7. parallel I/O interface 8. timer 9. serial I/O interface ATMEL 89 series 51 microcontroller application area At present, ATMEL 51 has been widely used for: - Printer control board - Smart meter - Smart meter - Smart meter - Smart meter Printer control boards - Smart meters - LED control panels - Medical devices 89s51 Microcontroller The AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller manufactured by ATMEL, with 4k bytes of system-programmable Flash Read-Only Program Memory on board. The device is produced using ATMEL's high-density, non-volatile memory technology and is compatible with the standard 8051 instruction system and pinout. The device is produced using ATMEL's high-density, non-volatile memory technology and is compatible with the standard 8051 instruction system and pinout. It is a set of Flash program memory can be both online programming (ISP) can also be) IJ traditional method of programming and general-purpose 8-bit microprocessor in a single chip, ATMEL's powerful, low-cost AT89S51 microcontroller can provide you with many cost-effective applications, can be flexibly applied to a variety of control areas.　　Key Performance Parameters: -Fully compatible with MCS-51 product instruction system -4k bytes of In-System Programming (ISP) Flash memory -1000 erase/write cycles -4. 0-5. 5V operating voltage range -Full static mode: OHz-33MHz -Three levels of program encryption locking -128X8 bytes of internal RAM -32 programmable I/0 lines -2 16-bit timers/counters -2 16-bit timer/counters -3 level of program locking -128X8 bytes of internal RAM -32 programmable I/0 lines -2 programmable I/O lines -16-bit timers/counters 16-bit timer/counter -6 interrupt sources -Full duplex serial Lh1RT channel -Low power idle and power-down modes . Interrupt can wake up the system from idle mode -Watchdog (WDT) and dual data pointers -Power-down identification and fast programming features -Flexible in-system programming (iSP one-byte or page-write modes) Functionality Overview: The AT89S51 provides the following standard features: 4k bytes of Flash memory, 128 bytes of internal RAM, 32 I/O lines, watchdog (WDT), two data pointers, two 16-bit timer/counters, and two 16-bit timer/counters. data pointer, two 16-bit timers/counters, a 5-vector two-level interrupt structure, a full-duplex serial communication port, an on-chip oscillator and clock circuit. Meanwhile, the AT89S51 can drop down to OHz static logic operation and supports two software-selectable power-saving modes of operation. The idle mode stops cPu operation but allows the RAM, timer/counter, serial communication port and, interrupt system to continue working. Power-down mode saves the contents of RAM, but stops the oscillator and disables all other components until the next hardware reset.