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1、-可以编辑的精品文档，你值得拥有，下载后想怎么改就怎么改-=AT89S52Features Compatible with MCS-51 Products 8K Bytes of In-System Programmable (ISP) Flash Memory 1000 Write/Erase Cycles Fully Static Operation: 0 Hz to 33 MHz Three-level Program Memory Lock 256 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Cou
2、nters Eight Interrupt Sources Full Duplex UART Serial Channel Low-power Idle and Power-down Modes Interrupt Recovery from Power-down Mode Watchdog Timer Dual Data Pointer Power-off FlagDescriptionThe AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system progr
3、ammable Flash memory. The device is manufactured using Atmels high-density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. The on-chip Flash allows the programmemory to be reprogrammed in-system or by a conventional nonvolatile memory prog
4、rammer.By combining a versatile 8-bit CPU with in system programmable Flash on a monolithicchip, the Atmel AT89S52 is a powerful icrocontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.The AT89S52 provides the following tandard features: 8K b
5、ytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator,and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down t
6、o zero frequency and supports two software selectable power saving modes.The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip func
7、tions until the next interrupt or hardware reset.Pin ConfigurationsBlock DiagramPin DescriptionVCCSupply voltage.GNDGround.Port 0Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as hi
8、gh- impedance Inputs.Port 0 can also be configured to be the multiplexed loworder address/data bus during ccesses to external program and data memory. In this mode, P0 has int -ernal pullups.Port 0 also receives the code bytes during Flash programming and outputs the code bytes dur -ing program veri
9、fication.External pullups are required during program veri- fication.Port 1Port 1 is an 8-bit bidirectional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins, they are pulled high bythe internal pullups and can be used as inpu
10、ts. As inputs,Port 1 pins that are externally being pulled low will sourcecurrent (IIL) because of the internal pullups.In addition, P1.0 and P1.1 can be configured to be the ti -mer/counter 2 exte- rnal count input (P1.0/T2) and the timer/counter 2 trigger input(P1.1/T2EX), respectively, as shown i
11、n the following table.Port 1 also receives the low-order address bytes during Flash programming and verification.Port PinAlternate FunctionsP1.0T2 (external count input to Timer/Counter 2),clock-outP1.1T2EX (Timer/Counter 2 capture/reload trigger and direction control)P1.5MOSI (used for In-System Pr
12、ogramming)P1.6MISO (used for In-System Programming)P1.7SCK (used for In-System Programming)Port 2Port 2 is an 8-bit bidirectional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins, they are pulled high bythe internal pullups a
13、nd can be used as inputs. As inputs,Port 2 pins that are externally being pulled low will sourcecurrent (IIL) because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses toexternal data memory that use 16-bit ddresses (MOVX
14、 DPTR). In this application, Port 2 uses strong internal pullups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX RI), Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-order address bits and some control signals durin
15、g Flash programming and verification.Port 3Port 3 is an 8-bit bidirectional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins,they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups. Port 3 also serves the functions of various special featuresof the AT89S52, as shown in the following table.Port 3 also receives some control signals for Flash progra
