1、附录 A 原文： FreescaleSingle-chip Microcomputer s in automobile control application Freescale has the rich micro processing unit (MCU), but widely uses in the automobile electrically controlled engine, the automobile body, the crew member safety, the vehicle door and the chair, the glass, ventilation an
2、d air conditioning, skylightand light control, automobile local area networks gateway, communication facility, global positioning system and in other automobile control unit. Its product mainly includes 8/16 bit micro controller (including HC08/HCS08, HC12/HCS12 and so on), 32 bit micro controllers
3、(including PowerPC, ColdFire, ARM and so on) 1. 8 bit Single-chip Microcomputer MC68HC11F1 and application 1.1 Characteristicsof MC68HC11F1 8 bit micro controllerMC68HC11F1 is high performance flash memory technology low cost chip based on the CPU of 8 bit HC08 the CPU . Its dozens of kind of differ
4、ent specifications product may cause the user to make a choice conveniently, the superior price performance ratio may cause the cost of the automobile electronic products to be more inexpensive. Chief feature of MC68HC11F1 : Two kind of power saving mode, stop and waiting； working normal in 3.0-5.0V
5、 voltage ； 0, 256b, 512b or 768b in on-chip RAM, Data of RAM will be retained in standby； 0, 12kb or 20kb inon-chip RAM or EPROM； Serical Communication InterfaceSCI,8 channel, 8 bit A/D transducer ； 16 bit timer systems； 8 bit pulse accumulators, real-time interrupt electric circuit and so on. 1.2 M
6、C68HC11F1is employed inin automobile electronic control system Since Marelli simple point electronic fuel injectionn engine management system is promoted based on MC68HC11F1,our country Shenyang gold cup sea lion passenger car , the gold cup China passenger vehicle, AnhuiChery passenger vehicle, the
7、 Tianjin Xiali passenger vehicle and so on has used this kind of engine management system . Below to take gold cup simple point Marelli logic circuit for an example, I introducesMC68HC11F1 employed inin automobile electronic control system. 1.2.1 Compositions of system As shown in Figure 1, gold cup
8、 simple point Marelli logic circuit is mainly composed of the below part: 1. Electric circuits control core MC68HC11F1 (CPU), is Freescale 8 bit MCU of automobile special-purpose ； 2. Tristate bus driver 74HC244 with enable, is the switch of status information input for air conditioning, oil pump, E
9、VAP solenoid valve, idling motor and so on ； 3. 8 groups rises along D trigger74HC273 with reset , isdriving signaltake-off valves for idling motor, host relay, trouble lamp, air conditioning relay power and so on； 4. 512kb 8 bit read-only memory M27C512, uses for to save computers master routine. R
10、eset Date Bus Figure 1 gold cup simple point Marelli logic circui 1.2.2 principles of work Puting through the power source, power source chip L9710 starts to provide the work power source and sensors reference voltage, the 8th foot output the low electric potential reset signal and delivers to reset
11、 end of the CPU, simultaneously delivers to zero clearing end of 74HC273 to makeits output end reset , CPU to enter launching state. First carries on the replacement to the internal hardware, establishes corresponding register, then starts Boot loader procedure, carries on the procedure loading. Rea
12、ds master routineintheM27C512 in internal RAM , and enters run condition of the programthrough the skipping instruction. The master routine outputs logic “1” (high electric potential) through data bus D2 , after this signal is locked by the 74HC273 outputingthe high electric potential control signal
13、 from the 6th foot,makes the main relay go through， Adds the 12V power source to the external instrumentation such as the fuel injector the ignition coil and so on . Then readin rotational speed signal and the exterior sensor signal through PA, PE, to judgethe vehicles current operating condition, a
14、nd according to the current operating mode outputs the corresponding driving signalfrom PD, PG mouth and the data bus ( locked by the 74HC273 )to make the equipment enter the running status . Again reads in the corresponding equipments status messagesthrough PA, PD, PG and the data bus (drived by th
15、e 74HC244 ), carries on the comparison withcontrol rule chart of the M27C512 , tooptimizate and adjustignition timing and spurts oil systems control. The logic circuit, the sensor and the implementing agency constitutionmake up of closed-loop control system to make the engine be at the optimum condi
16、tion. PortAPortD CPU PortGPortE PortB.FPortC driver driver Little fire oil injection logic Diagnosis interface A/D Signal adjustment M27C512 74HC244 74HC273 L9170 Device state information Automobile active status sensor signal driver air conditioning, breakdown lights, host relay, idling regime Signal adjustment
