1 foreword
Because,the real reason that car happening traces remaining part is around car " brake is different pace " . When slam the brakes on, hind car driver from beginning to end lag at before car, to the speed of 120km ／ H, need develops 17 meters more ahead. Even if develop 1 meter less ahead, produce an accident that trace remaining part less perhaps. Rate of respond of LED car lamps and lanterns is rapid, differentiate the effect is good, be able to bear or endure shake sex is strong wait for character. System of light of intelligent LED scram is to be when car scram, use the character with LED exceedingly good light to illume quickly brake lamp, the car after caution, avoid accident happening thereby. The article with ATmega8L sheet piece machine give out for core the design program of lamp of brake of LED of a kind of intelligence, this system design uses acceleration sensor to get the change of car acceleration quickly, transmit the result to ATmega8L sheet piece machine, ATmega8L is odd the information that receives to receiving again has an opportunity judgement, processing, whether to illume according to result decision scram lamp.
Type selecting of 2 parts of an apparatus
2. 1ATmega8L brief introduction
This systematic design chooses the AT-mega8L parts of an apparatus that American Atmel company rolls out, it is the low power comsumption that is based on buildup AVRRISC structure 8 CMOS small controller, increase model what Flash carries inside RISC is odd a machine, piece on Flash memory is added in user product, but at any time process designing, easily user products plan, facilitating product is newer. AT-mega8L has advanced instruction collect and instruction of odd clock cycle to execute time, its data takes in and send out in large quantities rate be as high as 1MIPS ／ MHz, alleviate thereby the systematic contradiction between power comsumption and processing speed. In the meantime, ATmega8L interior is compositive have enhance RISC8 CPU and online system process designing and the Flash memory that use process designing, make its make the sheet with powerful function piece machine, for a lot of embedded control application was offerred agile and the solution of low cost.
Inside the system of ATmega8L embedded 8KB but process designing Flash(is had read written capability at the same time, namely RWW) , 512 byte EEPROM, 1KBSRAM, line of port of O of ／ of 32 general I, register of 32 current jobs, 3 have the quick timer ／ tally that compares pattern (T ／ C) , piece inside interrupt outside ／ , but process designing is serial USART, the two lines that face byte are serial interface, 10 6 (8 are enclosed for TQFP and MLF) converter of A ／ D, have piece inside of the oscillator but timer of process designing watchdog, serial port of a SPI, and 5 kinds of mode omiting report that can choose through software.
2. 2MMA1260D brief introduction
This systematic design chooses MMA1260D to regard acceleration as sensor. MMA1260D is 1. The sensor of Z axial acceleration of 5g, it recuperates ASIC circuit by G- unit and signal two parts composition. Among them, g- unit is rigid structure, use semiconductor to make a technology, make by material of polycrystalline silicon semiconductor, and sealed. And circuit of signature manage ASIC is compensate by wave of integral, enlarge, filter, temperature, control logic and EEPROM are relevant builder of circuit, oscillator, clock, and the circuit composition such as self check, be worth the changeover that outputs to voltage with the electric capacity that gauges at completing G- unit.
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