基于51单片机信号发生器的设计——外文翻译

1、.西安交通大学城市学院本科生毕业设计（外文翻译） 本 科 毕 业 设 计 论 文 题 目 The SCM and Vision2 所在系 电气与信息工程系 学生姓名 冉乾乾 专 业 电子信息工程 班 级 电信002 学号 10010085 指导教师 金印彬 2014 年 5 月 The SCM and µVision2一、 Principle of MCUSingle-chip is an integrated on a single chip a complete computer system. Even though most of his features in a smal

2、l chip, but it has a need to complete the majority of computer components: CPU, memory, internal and external bus system, most will have the Core. At the same time, such as integrated communication interfaces, timers, real-time clock and other peripheral equipment. And now the most powerful single-c

3、hip microcomputer system can even voice, image, networking, input and output complex system integration on a single chip. Also known as single-chip MCU (Microcontroller), because it was first used in the field of industrial control. Only by the single-chip CPU chip developed from the dedicated proce

4、ssor. The design concept is the first by a large number of peripherals and CPU in a single chip, the computer system so that smaller, more easily integrated into the complex and demanding on the volume control devices. INTEL the Z80 is one of the first design in accordance with the idea of the proce

5、ssor, From then on, the MCU and the development of a dedicated processor parted ways. Early single-chip 8-bit or all of the four. One of the most successful is INTEL's 8031, because the performance of a simple and reliable access to a lot of good praise. Since then in 8031 to develop a single-ch

6、ip microcomputer system MCS51 series. Based on single-chip microcomputer system of the system is still widely used until now. As the field of industrial control requirements increase in the beginning of a 16-bit single-chip, but not ideal because the price has not been very widely used. After the 90

7、's with the big consumer electronics product development, single-chip technology is a huge improvement. INTEL i960 Series with subsequent ARM in particular, a broad range of applications, quickly replaced by 32-bit single-chip 16-bit single-chip high-end status, and enter the mainstream market.

8、Traditional 8-bit single-chip performance has been the rapid increase in processing power compared to the 80's to raise a few hundred times. At present, the high-end 32-bit single-chip frequency over 300MHz, the performance of the mid-90's close on the heels of a special processor, while the

9、 ordinary price of the model dropped to one U.S. dollars, the most high-end models, only 10 U.S. dollars. Contemporary single-chip microcomputer system is no longer only the bare-metal environment in the development and use of a large number of dedicated embedded operating system is widely used in t

10、he full range of single-chip microcomputer. In PDAs and cell phones as the core processing of high-end single-chip or even a dedicated direct access to Windows and Linux operating systems. More than a dedicated single-chip processor suitable for embedded systems, so it was up to the application. In

11、fact the number of single-chip is the world's largest computer. Modern human life used in almost every piece of electronic and mechanical products will have a single-chip integration. Phone, telephone, calculator, home appliances, electronic toys, handheld computers and computer accessories such

12、 as a mouse in the Department are equipped with 1-2 single chip. And personal computers also have a large number of single-chip microcomputer in the workplace. Vehicles equipped with more than 40 Department of the general single-chip, complex industrial control systems and even single-chip may have

13、hundreds of work at the same time! SCM is not only far exceeds the number of PC and other integrated computing, even more than the number of human beings.Hardwave introductionThe 8051 family of micro controllers is based on an architecture which is highly optimized for embedded control systems. It i

14、s used in a wide variety of applications from military equipment to automobiles to the keyboard on your PC. Second only to the Motorola 68HC11 in eight bit processors sales, the 8051 family of microcontrollers is available in a wide array of variations from manufacturers such as Intel, Philips, and

15、Siemens. These manufacturers have added numerous features and peripherals to the 8051 such as I2C interfaces, analog to digital converters, watchdog timers, and pulse width modulated outputs. Variations of the 8051 with clock speeds up to 40MHz and voltage requirements down to 1.5 volts are availabl

16、e. This wide range of parts based on one core makes the 8051 family an excellent choice as the base architecture for a company's entire line of products since it can perform many functions and developers will only have to learn this one platform. The basic architecture consists of the following

17、features: an eight bit ALU 32 descrete I/O pins (4 groups of 8) which can be individually accessed two 16 bit timer/counters full duplex UART 6 interrupt sources with 2 priority levels 128 bytes of on board RAM separate 64K byte address spaces for DATA and CODE memoryOne 8051 processor cycle consist

18、s of twelve oscillator periods. Each of the twelve oscillator periods is used for a special function by the 8051 core such as op code fetches and samples of the interrupt daisy chain for pending interrupts. The time required for any 8051 instruction can be computed by dividing the clock frequency by

19、 12, inverting that result and multiplying it by the number of processor cycles required by the instruction in question. Therefore, if you have a system which is using an 11.059MHz clock, you can compute the number of instructions per second by dividing this value by 12. This gives an instruction fr

20、equency of 921583 instructions per second. Inverting this will provide the amount of time taken by each instruction cycle (1.085 microseconds).二、 The Introduction of AT89C511 DescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and eras

21、able read only memory (PEROM). The device is manufactured using Atmels high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory prog

22、rammer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.2 Function characteristicThe AT89C51 provides the following standard features:

23、4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, one 5 vector two-level interrupt architecture, a full duplex serial port, one-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports tw

24、o 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 functions until the next hardware res

25、et.Pin DescriptionVCC：Supply voltage.GND：Ground.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 may also be configured to be the multiplexed a

26、ddress/data bus during accesses to external program and data memory. In this mode P0 has internal Pull-up resistor. Port 0 also receives the code bytes during Flash programming, and outputs the code bytes during Program verification. External Pull-up resistors are required during Program verificatio

27、n.Port 1Port 1 is an 8-bit bi-directional I/O port with internal Pull-up resistors. 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-up resistors and can be used as inputs. As inputs, Port 1 pins that are external

28、ly being pulled low will source current (IIL) because of the internal Pull-up resistors. Port 1 also receives 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-up resistor. The Port 2 output buffers can sink/sour

29、ce four TTL inputs. When 1s are written to Port 2 pins they are pulled high by the internal Pull-up resistor and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current, because of the internal Pull-up resistor. Port 2 emits the high-order address byte

30、during fetches from external program memory and during accesses to external data memory that use 16-bit addresses. In this application, it uses strong internal Pull-up resistor when emitting 1s. During accesses to external data memory that use 8-bit addresses, Port 2 emits the contents of the P2 Spe

31、cial Function Register. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal Pull-up resistor. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written

32、to Port 3 pins they are pulled high by the internal Pull-up resistor and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the Pull-up resistor. Port 3 also serves the functions of various special features of the AT89C51 as listed

33、 below:Port 3 also receives some control signals for Flash programming and verification.RSTReset input. A high on this pin for two machine cycles while the oscillator is running resets the device.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address during accesses to ex

34、ternal memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation 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

35、 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 exec

36、ution mode.PSENProgram Store Enable is the read strobe to external program memory. When the AT89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Acces

37、s Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions

38、. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming, for parts that require12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit.XTAL2Output from the inverting oscillator amplifier.3 Oscillator Charac

39、teristicsXTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1.Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left

40、unconnected while XTAL1 is driven as shown in Figure 2.There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.

41、Figure 1. Oscillator Connections Configuration Figure2. External Clock Drive4 Idle ModeIn idle mode, the CPU puts itself to sleep while all the on chip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged

42、during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset. It should be noted that when idle is terminated by a hard ware reset, the device normally resumes program execution, from where it left off, up to two machine cycles before the internal reset algorithm

43、 takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when Idle is terminated by reset, the instruction following the one that invokes Idle should not be one that

44、 writes to a port pin or to external memory.5 Power-down ModeIn the power-down mode, the oscillator is stopped, and the instruction that invokes power-down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power-down mode is terminated. Th

45、e only exit from power-down is a hardware reset. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize.6 Program Memory

46、Lock BitsOn the chip are three lock bits which can be left unprogrammed (U) or can be programmed (P) to obtain the additional features listed in the table below.When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset. If the device is powered up without a res

47、et, the latch initializes to a random value, and holds that value until reset is activated. It is necessary that the latched value of EA be in agreement with the current logic level at that pin in order for the device to function properly.三、 Getting Started with µVision2The Keil Software 8051 d

48、evelopment tools listed below are programs you use to compile your C code, assemble your assembly source files, link and locate object modules and libraries, create HEX files, and debug your target program.µVision2 for Windows is an Integrated Development Environment that combines project manag

49、ement, source code editing, and program debugging in one single, powerful environment.The C51 ANSI Optimizing C Cross Compiler creates relocatable object modules from your C source code.The A51 Macro Assembler creates relocatable object modules from your 8051 assembly source code.The BL51 Linker/Loc

50、ator combines relocatable object modules created by the C51 Compiler and the A51 Assembler into absolute object modules.The LIB51 Library Manager combines object modules into libraries that may be used by the linker.The OH51 Object-HEX Converter creates Intel HEX files from absolute object modules.T

51、he RTX-51 Real-time Operating System simplifies the design of complex, time-critical software projects.Software Development CycleWhen you use the Keil Software tools, the project development cycle is roughly the same as it is for any other software development project. 1. Create a project, select th

52、e target chip from the device database, and configure the tool settings.2. Create source files in C or assembly.3. Build your application with the project manager.4. Correct errors in source files.5. Test the linked application.µVision2 IDEThe µVision2 IDE combines project management, a ri

53、ch-featured editor with interactive error correction, option setup, make facility, and on-line help. Use µVision2 to create your source files and organize them into a project that defines your target application. µVision2 automatically compiles, assembles, and links your embedded applicati

54、on and provides a single focal point for your development efforts.LIB51 Library ManagerThe LIB51 library manager allows you to create object library from the object files created by the compiler and assembler. Libraries are specially formatted, ordered program collections of object modules that may

55、be used by the linker at a later time. When the linker processes a library, only those object modules in the library that are necessary to create the program are used.BL51 Linker/LocatorThe BL51 linker creates an absolute object module using the object modules extracted from libraries and those crea

56、ted by the compiler and assembler. An absolute object file or module contains no relocatable code or data. All code and data reside at fixed memory locations. The absolute object file may be used: To program an EPROM or other memory devices, With the µVision2 Debugger for simulation and target

57、debugging, With an in-circuit emulator for the program testing.µVision2 DebuggerThe µVision2 symbolic, source-level debugger is ideally suited for fast, reliable program debugging. The debugger includes a high-speed simulator that let you simulate an entire 8051 system including on-chip pe

58、ripherals and external hardware. The attributes of the chip you use are automatically configured when you select the device from the Device Database.The µVision2 Debugger provides several ways for you to test your programs onreal target hardware: Install the MON51 Target Monitor on your target

59、system and download your program using the Monitor-51 interface built-in to the µVision2 Debugger.Ø Use the Advanced GDI interface to attach use the µVision2 Debugger front end with your target system.Monitor-51The µVision2 Debugger supports target debugging using Monitor-51. The monitor program resides in the memory of your ta