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1、电子与信息工程学院 本科毕业论文(设计)外 文 文 献 翻 译译文题目： 8-bit Microcontroller With 8K Bytes Flash AT89C52 学生姓名： 吴远超 专 业： 电气工程及其自动化 指导教师： 倪 浩 2012年11月 外文资料8-bit Microcontroller With 8K Bytes Flash AT89C52FeaturesCompatible with MCS-51 Products8K Bytes of In-System Reprogrammable Flash MemoryEndurance: 1,000 Write/Erase
2、 CyclesFully Static Operation: 0 Hz to 24 MHzThree-level Program Memory Lock256 x 8-bit Internal RAM32 Programmable I/O LinesThree 16-bit Timer/CountersEight Interrupt SourcesProgrammable Serial ChannelLow-power Idle and Power-down ModesDescriptionThe AT89C52 is a low-power, high-performance CMOS 8-
3、bit microcomputer with 8K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmels high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pin out. The on-chip Flash allows the progr
4、am memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C52 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applicati
5、ons.Pin ConfigurationsBlock DiagramPin DescriptionVCCSupply voltage.GNDGround.Port 0Port 0 is an 8-bit open drain bi-directional 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 high-impedance inputs. Port 0 can also be conf
6、igured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull-ups are required dur
7、ing program verification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are ex
8、ternally being pulled low will source current (IIL) because of the internal pull-ups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the following table. Port 1 also re
9、ceives the low-order address bytes during Flash programming and verification. Port 2Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull-ups and can
10、be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memories that use 16-bit addresses (MOV
11、X DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memories 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
12、during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. 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 pull-ups and can be used as inputs. As inputs, Port 3
13、 pins that are externally being pulled low will source current (IIL) because of the pull-ups.Port 3 also serves the functions of various special features of the AT89C51, as shown in the following table. Port 3 also receives some control signals for Flash programming and verification.RSTReset input.
14、A high on this pin for two machine cycles while the oscillator is running resets the device.ALE/Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input () during Flash programming. In normal operati
15、on, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.Program
