AT89C51外文翻译 外文文献 英文文献.docx

《AT89C51外文翻译 外文文献 英文文献.docx》由会员分享，可在线阅读，更多相关《AT89C51外文翻译 外文文献 英文文献.docx（26页珍藏版）》请在第一文库网上搜索。

1、AT89C51外文翻译DescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4Kbytes of Flash Programmable and Erasable Read Only Memory (PEROM). Thedevice is manufactured using Atmcs high density nonvolatile memory technologyand is compatible with the industry standard MCS-51 in

2、struction-set and pinout.The on-chip Flash allows the program memory to be reprogrammed in-system or by aconventional nonvolatile memory programmer. By combining a versatile 8-bit CPUwith Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputerwhich provides a highly flexible and co

3、st effective solution to many embeddedcontrol applications.Features Compatible with MCS-51 Products 4K Bytes of In-System Reprogrammable Flash Memory Endurance: 1,000 Write/Erase Cycles Fully Static Operation: 0 Hz to 24 MHz Three-Level Program Memory Lock 128 x 8-Bit Internal RAM 32 Programmable I/

4、O Lines Two 16-Bit Timer/Counters Six Interrupt Sources Programmable Serial Channel Low Power Idle and Power Down ModesThe AT89C51 provides the following standard features: 4K bytes of Flash J 28 bytesPort 0Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin cansink ei

5、ght TTL inputs. When Is are written to port 0 pins, the pins can be used ashigh-impedance inputs.Port 0 may also be configured to be the multiplexed low-order address/data bus duringaccesses to external program and data memory. In this mode P0 has internal pullupsPort 0 also receives the code bytes

6、during Flash programming, and outputs the codebytes during program verification. External pullups are required during programverification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output bufferscan sink/source four TTL inputs.When Is are written to Port 1 pins

7、 they are pulledhigh by the internal pullups and can be used as inputs. As inputs,Port 1 pins that areexternally being pulled low will source current (11L) because of the internalpullups.Port 1 also receives the low-order address bytes during Flash programmingand verification.Port 2Port 2 is an 8-bi

8、t bi-directional I/O port with internal pullupsThe Port 2 output bufferscan sink/source four TTL inputs.When Is are written to Port 2 pins they are pulledhigh by the internal pullups and can be used as inputs. As inputs,Port 2 pins that areexternally being pulled low will source current (IIL) becaus

9、e of the internal pullups.Port 2 emits the high-order address byte during fetches from external programmemory and during accesses to external data memory that use 16-bit addresses(MOVX DPTR). In this application, it uses strong internal pullups when emitting Is.Port PinAlternate FunctionsP3.0RXD (se

10、rial input port)P3.1TXD (serial output port)P3.2INTO (external interrupt 0)P3.3INT1 (external interrupt 1)P3.4TO (timer 0 external input)P3.5T1 (timer 1 external input)P3.6WR (external data memor, write strobe)P3.7RD (external data memory read strobe)Port 3 also receives some control signals for Fla

11、sh programming and verification.RSTReset input. A high on this pin for two machine cycles while the oscillator is runningresets the device.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address duringaccesses to external memory. This pin is also the program pulse input (P

12、ROG) duringFlash programming. In normal operation ALE is emitted at a constant rate of 1/6 theoscillator frequency, and may be used for external timing or clocking purposes. Note,however, that one ALE pulse is skipped during each access to external DataMemory.If desired, ALE operation can be disable

13、d by setting bit 0 of SFR location 8EH. Withthe bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, thepin is weakly pulled high. Setting the ALE-disable bit has no effect if themicrocontroller is in external execution mode.PSENProgram Store Enable is the read strobe to externa

14、l program memory. When theAT89C51 is executing code from external program memory, PSEN is activated twiceeach machine cycle, except that two PSEN activations are skipped during each accessto external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device t

15、ofetch code from external program memory locations starting at ()()00H up toFFFFH.Note5 however, that if lock bit 1 is programmed, EA will be internally latchedon reset. EA should be strapped to VCC for internal program executions.This pin alsoreceives the 12-volt programming enable voltage (VPP) during Flash programming,for parts that require 12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operatingcircuit.XTAL2Output from the inverting oscillator amplifienOscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respe