[single chip microcomputer] 2.1 hardware composition of AT89S52 single chip microcomputer

Learning resources ： Hardware structure of single chip microcomputer

2.1 AT89S52 Hardware composition of single chip microcomputer

（1）8 Bit microprocessor （CPU）;
（2） Data storage （256B RAM）;
（3） Program memory （8KB Flash ROM）;
（4）4 individual 8 Bit programmable parallel I/O mouth （P0 mouth 、P1 mouth 、P2 Mouth and P3 mouth ）;
（5）1 A full duplex asynchronous serial port ;
（6）3 A programmable 16 Bit timer / Counter （T0、T1 and T2）;
（7）1 A watchdog timer ;
（8） The interrupt system has 6 Broken source 、6 Interrupt vectors ;
（9） special function register （SFR）32 individual ;
（10） Low power consumption modes include idle mode and power down mode , And it has interrupt recovery mode under power failure mode ;
（11）3 Program encryption lock location .

   All functional components in the chip are connected by a single bus , The basic structure Is still CPU The traditional microcomputer structure with peripheral chips .

  CPU Special function registers are used to control various functional components （SFR,Special Function Register） Centralized control mode .
   The following is an introduction to figure 2-1 All functional parts in the middle piece :

（1）CPU（ Microprocessor ）

  8 Bit CPU, And general CPU Basically the same , It also includes Arithmetic unit and controller Two major parts , also Control oriented bit processing function .

（2） Data storage （RAM）

   Intraslice For the purpose of 256B, Off slice Up to 64KB. Intraslice 256B Of RAM At high speed RAM Formal integration of , It can speed up the operation of single chip microcomputer and reduce power consumption .

（3） Program memory （Flash ROM）

   Used to store programs .AT89S52 Intraslice Yes 8KB Of Flash Memory ; If the on-chip program memory capacity is insufficient , Off slice It can be expanded to 64KB Program memory , namely “ Intraslice + Off slice ” The program memory of The total capacity does not exceed 64KB.

（4） Timer / Counter

   In the film 3 individual 16 Bit timer / Counter , have 4 Ways of working .

（5） Interrupt the system

   have 6 individual Interrupt source ,2 level Interrupt priority .

（6） Serial port

   1 individual full duplex Asynchronous serial port ,4 Ways of working . Serial communication is possible , Extended parallelism I/O mouth , It can form a multi computer system with multiple single-chip computers .

（7）P0 mouth 、P1 mouth 、P2 Mouth and P3 mouth

   4 individual 8 Bit parallel I/O mouth .

（8） special function register （SFR）

   share 32 individual special function register , be used for CPU Manage the peripherals in the chip 、 Control and monitor . The special function register is actually the control register and status register of each peripheral component in the chip , These special function registers Map on-chip RAM District Of 80H～FFH Within the address range of .

（9）1 A watchdog timer WDT

   When the single-chip microcomputer makes the program fall into a dead cycle or fly state due to interference , Can cause MCU reset , Return the program to normal operation .

   AT89S52 Fully compatible with AT89C51/AT89S51 Single chip microcomputer , Use AT89C51/AT89S51 SCM system , On the basis of retaining the original software and hardware , You can use AT89S52 Direct substitution .