Engineering Project Management(2) Course paperTitle:Specialty：Taxi meterClass：H1303Name：Han TongLi XinhaoStudent ID：CATALOGCATALOG一、一、INTRODUCTIONINTRODUCTION.1 1二、二、OVERALLOVERALL DESIGNDESIGN SCHEMESCHEME.1 1（一）（一） 、S SOFTWAREOFTWARE ANDAND HARDWAREHARDWARE FLOWFLOW CHARTCHART.2 2（二）（二） 、S SOURCEOURCE PROGRAMPROGRAM DESIGNDESIGN ANDAND HARDWAREHARDWARE INTRODUCTIONINTRODUCTION.5 52.12.1 80868086 minimumminimum systemsystem modulemodule .5 52.22.2 ChipChip 8255A8255A .6 62.32.3 ChipChip 82538253 .7 72.4Programmable2.4Programmable controlcontrol chipchip 8259A8259A .8 8（三）（三） 、P PROBLEMSROBLEMS ENCOUNTEREDENCOUNTERED.9 9三、三、SUMMARYSUMMARY ANDAND EXPERIENCEEXPERIENCE.1010四、四、REFERENCEREFERENCE：.1010APPENDIXAPPENDIX.11110一、IntroductionTaximeter is both passengers and drivers of the trade standards, it is an important symbol of the development of the taxi industry, is in a taxi is the most important tool. It is related to the interests of the parties to the transaction. With good performance of the meter whether is very necessary for the majority of taxi drivers or passengers. Therefore, the automobile valuation of is an application value.Our country in the 1970s began to taxi, but then the billing system mostly imported not only accurate, price is also very expensive. With the deepening of reform and opening up, the development momentum of the taxi industry has been very prominent, the domestic machinery manufacturers have launched domestic meter. Taxi valuation functions from at the beginning of the show only away (the driver himself pricing, calculated after four homes in five), to independent billing, and now can play an invoice and a voice prompt, according to time independent changes in price function. With the development of urban tourism, the taxi industry has become the citys window, a symbol of the civilization of a city Degree.With the development of the taxi industry, the taxi is an important 1part of urban traffic, starting from strengthening the industry management and reduce disputes of driver and passenger, with good performance meter to taxi drivers and passengers are very necessary. We design the 8086 based controller, to a44e Hall sensor location, on the taxi multifunctional pricing design, the output of the 8 digital tube display.二、Overall design schemeBy 8253 as timer / counter, motor speed and measurement of motor speed control; 8255 as input and output interface, control digital tube display after the start mileage (after the decimal point from two effective value).Hardware connection description:Based on the DC motor controller, a motor speed measurement circuit is added.B the 8255 port as digital tube stroke code driven; the low four bits of a C port as the segment code control, showing the actual mileage. At the same time, also for the keyboard output column scan code; PC6 and PC7 input line scan code for the key identification, procedure using only the PC6 four buttons, which is defined as follows:2X1: start / stop button; X2: accelerator key, and X3, X4 key combination to use; X3: “+“ button; X4: “-“ key.A mouth only uses the PA0, the output PWM pulse signal, by driving the motor, the output voltage is proportional to the duty cycle of the PWM pulse.The number of revolutions of the motor, through the hall element transformation for pulse number, into the 8253 passage 2, counting, speed is converted to mileage, the smallest unit is 0.01 km, send the recorded CPU. The results by the digital tube display.3（一）（一） 、Software and hardware flow chartad7ad0ad4 ad5ad1 ad2 ad3ad6D034D133D232D331D430D529D628D727RD5WR36A09A18RESET35CS6PA04PA13PA22PA31PA440PA539PA638PA737PB018PB119PB220PB321PB422PB523PB624PB725PC014PC115PC216PC317PC413PC512PC611PC710U28255AAD0.15 READY22INTR18NMI17RESET21CLK19MN/MX33HOLD/GT131HLDA/GT030A16.19M/IO/S028ALE/QS025DT/R/S127INTA/QS124TEST23BHE34DEN/S226RD32WR/LOCK29U18086IR018IR119IR220IR321IR422IR523IR624IR725INT17INTA26CS1WR2RD3A027SP/EN16D0.