(完整版)_毕业设计英文文献51单片机中英文文献翻译_

AT89C51的概况The General Situation of AT89C51Chapter 1 The application of AT89C51Microcontrollers are used in a multitude of commercial applications such as modems, motor-control systems, air conditioner control systems, automotive engine and among others. The domains also require that these microcontrollers are be ensured by a robust testing process and a proper tools environment for the validation of these microcontrollers both at the component and at the system level. Intel Plaform Engineering department developed anobject-oriented multi-threaded test environment for the validation of its AT89C51 automotive microcontrollers. The goals of thisenvironment was not only to provide a robust testing environment for the AT89C51 automotive microcontrollers, but to develop an environment which can be easily extended and reused for the validation of several other future microcontrollers. The environment was developed in conjunction with Microsoft Foundation Classes (AT89C51). The paper describes the design and mechanism of this test environment, its interactions with variousThe 8-bit AT89C51 CHMOS microcontrollers are designed to engine-control systems, airbags, suspension systems, and antilock braking systems (ABS). The AT89C51 is especially well suited to applications that benefit from its processing speed and enhancedon-chip peripheral functions set, such as automotive power-train control, vehicle dynamic suspension, antilock braking, and stability control applications. Because of these critical applications, the market requires a reliable cost-effective controller with a low interrupt latency response, ability to service the integrated peripherals needed in real time applications, and a CPU with above average processing power in a single package. The financial and legal risk of the market, particularly in mission criticalapplications such as an autopilot or anti-lock braking system, mistakes are financiallyprohibitive. Redesign costs can run as flaw. In addition, field replacements of components is extremely expensive, as the devices are typically sealed in modules with a total value several times that of the component. To mitigate these problems, it is essential that comprehensive testing of the controllers be carried out at both the component level and system level under worst case environmental and voltage conditions.This complete and thorough validation necessitates not only a well-defined process but also a proper environment and tools to facilitate and execute the mission successfully.Intel Chandler Platform Engineering group provides post silicon system validation (SV) of various micro-controllers and processors. The system validation process can be broken into three major parts.The type of the device and its application requirements determine which types of testing are performed on the device.1.2 The AT89C51 provides the following standard features:4Kbytes of Flash, 128 bytes of RAM, 32 IO lines, two 16-bittimercounters, a five vector two-level interrupt architecture,a full duple ser -ial port, on-chip oscillator and clock circuitry.In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timercounters,serial port and interrupt sys -tem to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscil –lator disabling all other chip functions until the next DescriptionVCC Supply voltage.GND Ground.Port 0：Port 0 is an 8-bit open-drain bi-directional IO port. As an output port, each pin cansink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as this mode P0 . External pullups are required during programverification.Port 1：Port 1 is an 8-bit bi-directional IO port with internal pullups.The Port 1 output buffers can sinkso -urce four TTL inputs.When 1s are written to Port 1 pins they are pulled be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2：Port 2 is an 8-bit bi-directional IO port with internal pullups.The Port 2 outputbuffers can sinksource four TTL inputs.When 1s are written to Port 2 pins they arepulled be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups. Port 2 emits the this application, it uses strong internal pull-ups 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 Flash programming and verification.Port 3：Port 3 is an 8-bit bi-directional IO port with internal pullups.The Port 3 outputbuffers can sinksou -rce four TTL inputs.When 1s are written to Port 3 pins they are pulled 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 AT89C51 as listed below:RST：Reset input. A this pin for two machine cycles while the oscillator is running resets the device.ALEPROG：Address Latch Enable output pulse for latching the low byte of the address duringaccesses to external memory.This pin is also the program pulse input (PROG) during Flash programming.In normal operation ALE is emitted at a constant rate of 16 the oscillator frequency,and may be used for external timing or clocking purposes. Note, be disabled by setting bit 0 of SFR location 8EH.With the bit set, ALE is active onlyduring a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled external execution mode.PSEN：Program Store Enable is the read strobe to external 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 access toexternal data memory.EAVPP：External Access Enable. EA must be strapped to GND in order to enable the deviceto fetch code from external program memory locations starting at 0000H up to FFFFH.Note, alsreceives the 12-volt programming enable voltage (VPP) during Flash programming, forparts that require 12-volt VPP.XTAL1：Input to the inverting oscillator amplifier and input to the internal clock operatingcircuit.XTAL2：Output from the inverting oscillator amplifier.Oscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifierwhich can be configured for use as an on-chip oscillator, as shown in Figure 1. Either aquartz crystal or ceramic resonator may be used. To drive the device from an externalclock source, XTAL2 should be left 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 idle mode, the CPU puts itself to sleep while all the onchip peripherals remainactive. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a idle is terminated by a ,from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip 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 writes to a port pin or to external memory.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. The only exit from power-down is a -chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be either programming mode. To program any nonblank byte in the on-chip Flash Memory, the entire memory must be erased using the Chip Erase Mode.2 Programming AlgorithmBefore programming the AT89C51, the address, data and control signals should be set up according to the Flash programming mode table and Figure 3 and Figure 4. To program the AT89C51, take the following steps.1. Input the desired memory location on the addresslines.2. Input the appropriate data byte on the data lines. 3. Activate the correct combination of control signals. 4. Raise EAVPP to 12V for the the Flash array or the lock bits. The byte-write cycle is self-timed and typically takes no more than 1.5 ms. Repeat steps 1 through 5, changing the address and data for the entire array or until the end of the object file is reached. Data Polling: The AT89C51 features Data Polling to indicate the end of a write cycle. During a write cycle, an attempted read of the last byte written will result in the complement of the written datum on PO.7. Once the write cycle completed, true data are valid on all outputs, and the next cycle may begin. Data Polling may begin any time after a write cycle initiated.2.1ReadyBusy:The progress of byte programming can also be monitored by the RDYBSY output signal. P3.4 is pulled low after ALE goes when programming is done to indicate READY.Program Verify:If lock bits LB1 and LB2 programmed, the programmed code data can be read back via the address and data lines for verification. The lock bits cannot be verified directly. Verification of the lock bits is achieved by observing that their features are enabled.Figure 2-1-1 Programming the Flash Figure 2-2-2 Verifying the Flash2.2 Chip Erase:The entire Flash array is erased electrically by using the proper combination of control signals and by with all “1”s. The chip erase operation must be executed before the code memory can be re-programmed.2.3 Reading the Signature Bytes:The signature bytes are read by the same procedure as a normal verification of locations 030H, 031H, and 032H, except that P3.6 and P3.7 must be pulled to a logic low. The values returned areas follows.(030H) = 1EH indicates manufactured by Atmel(031H) = 51H indicates 89C51(032H) = FFH indicates 12V programming(032H) = 05H indicates 5V programming2.4 Programming InterfaceEvery code byte in the Flash array can be written and the entire array can be erased by using the appropriate combination of control signals. The write operation cycle is selftimed and once initiated, will automatically time itself to completion. A microcomputer interface converts information between two forms. Outside the microcomputer the information electronic system exists as a physical signal, but within the program, it is represented numerically. The function of any interface can be broken down into a number of operations which modify the data in some way, so that the process of conversion between the external and internal forms is carried out in a number of steps. An analog-to-digital converter(ADC) is used to convert a continuously variable signal to a corresponding digital form which can take any one of a fixed number of possible binary values. If the output of the transducer does not vary continuously, no ADC is necessary. In this case the signal conditioning section must convert the incoming signal to a form which can be connected directly to the next part of the interface, the inputoutput section of the microcomputer itself. Output interfaces take a similar form, the obvious difference being that is in the opposite direction; it is passed from the program to the outside world. In this case the program may call an output subroutine which supervises the operation of the interface andperforms the scaling numbers which may be needed for digital-to-analog converter(DAC). This subroutine passesinformation in turn to an output device which produces a corresponding electrical signal, which could be converted into analog form using a DAC. Finally the signal is conditioned(usually amplified) to a form suitable for operating an actuator.The signals used within microcomputer circuits are almost always too small to be connected directly to the outside world” and some kind of interface must be used to translate them to a more appropriate form. The design of section of interface circuits is one of the most important tasks facing the engineer wishing to apply microcomputers. We that in microcomputers information is represented as discrete patterns of bits; this digital form is most useful when the microcomputer is to be connected to equipment which can only be switched on or off, where each bit might represent the state of a switch or actuator. To solve real-world problems, a microcontroller must just a CPU, a program, and a data memory. In addition, it must contain from the outside world. Once the CPU gathers information and processes the data, it must also be able to effect change on some portion of the outside world. These microcontrollers is the general purpose I70 port. Each of the IO pins can be used as either an input or an output. The function of each pin is determined by setting or clearing corresponding bits in a corresponding data direction register during the initialization stage of a program. Each output pin may be driven to either a logic one or a logic zeroby using CPU instructions to pin may be viewed (or read.) by the CPU using program instructions. Some type of serial unit is included on microcontrollers to allow the CPU to communicate bit-serially with external devices. Using a bit serial format instead of bit-parallel format requires fewer IO pins to perform the communication function, which makes it less expensive, but slower.Serial transmissions are performed either synchronously orasynchronously.翻译AT89C51的概况1 AT89C51应用单片机广泛应用于商业：诸如调制解调器，电动机控制系统，空调控制系统，汽车发动机和其他一些领域。