MM912－S812小型摩托车引擎ECU参考设计（特性_系统框图_电路图_pcb元件布局）

　　Freescale公司的MM912_S812是S12XS MCU和多功能点火和喷油器驱动系统，SiP集成了MCU（S12XS）和模拟控制芯片（MC33812），专门设计用于摩托车和其它单/双缸小引擎控制应用。工作范围4.7 V ≤ VPWR ≤ 36 V，继电器/点火/油泵驱动器电流4A，灯驱动电流1.5A， ISO-9141 K线收发器用于通信诊断信息。本文介绍了MM912_S812主要特性， MC9S12XS系列框图和33812简化内部框图， MM912_S812详细应用框图以及小型引擎参考设计KIT912S812ECUEVM主要特性和系统建立图， 小型摩托车引擎控制系统框图， 参考设计板KIT912S812ECUEVM系统框图，电路图，材料清单和PCB元件布局图。

　　The MM912_S812 is an engine control IC combining an MCU （S12XS） and analog control die （MC33812） intended for motorcycle and other single/dual cylinders small engine control applications. The MCU S12XS has 8.0 KB or 12 KB RAM， and flash memory size of 128 KB or 256 KB. The S12XS family retains many of the features of the S12XE family including error correction code （ECC） on flash memory， a separate data-flash module for code or data storage， a frequency modulated locked loop （IPLL） that improves the EMC performance and a fast ATD converter.

　　MM912_S812主要特性：

　　•Designed to operate over the range of ~4.7 V ≤ VPWR ≤ 36 V

　　•Relay/injector/fuel pump driver – current limit – 4.0 A， typical

　　•Lamp driver – current limit – 1.5 A， typical

　　•All external outputs protected against short to battery and overcurrent

　　•VCC voltage pre-regulator provides +5.0 V power for the MCU

　　• MCU watchdog timer circuit with parallel refresh/time setting line

　　• ISO-9141 K-Line transceiver for communicating diagnostic messages

图1. MC9S12XS系列框图

图2.33812简化内部框图

图3. MM912_S812简化应用框图

　　图4. MM912_S812详细应用框图

　　小型引擎参考设计KIT912S812ECUEVM

　　Welcome to the Freescale Small Engine Reference Design Kit. This product was designed to be a complete solution for the electronic control of a small engine. Small engines are defined as a one or two cylinder engine for use in anything from a motorbike to a lawn mower to a generator. While the decision was made to address a one-cylinder engine specifically， this design is extremely useful for a two-cylinder engine with little or no modification. Freescale’s concept of creating an engine control kit is intended to enable a market ranging from garage hobbyist to seasoned Tier 1 Powertrain Engineer using Freescale products.

　　Through the use of this kit， you can create an engine controller specific to a small engine application. Engine control is a discipline that requires intimate knowledge and experience in Chemical， Mechanical， and Electrical Engineering. For those familiar with mechanical control of an engine through a carburetor， the use of this reference design kit can help to advance your knowledge in the electrical area and provide a jump-start for a successful adoption of electrical engine controls to meet new emissions standards. Providing a kit such as this is intended to make semiconductor products from Freescale easier to use. The user is responsible for providing all input signals， output loads as well as the completed system design and development. This kit should serve as a starting point for the development of an application specific engine controller for a small engine. Example software and documentation are provided to assist in successful design and implementation. It is recommended to have the following skills and experience： embedded C-language programming， analog and digital circuit design and schematic analysis， microcontroller programming， fuel injection system debugging and calibration， and engine test environment experience. Additionally， there is further benefit to experiencing the CodeWarrior Development Studio and the Freescale S12X microcontroller Units （MCUs）。 The User Reference Manual provides exercises and references to additional information to reduce the learning curve for inexperienced users.

　　Freescale’s goal is to enable the small engine market. To clarify this point， the hardware included in this kit can readily be configured and reprogrammed to run an engine. However， it lacks the application specific hardening （EMC， ESD， and environmental areas for example） and implementation optimization that make it a production ready module for any specific application. Further， the free example application software provided is a starting point capable of running an engine. It does not apply any advanced control strategy capable of addressing the pollution concerns and regulations facing the small engine industry. To do this would become application specific to an engine and could not be and should not be implemented by a semiconductor supplier as it is deeply outside their area of expertise. The example application software does show how to use the key functionality in the Freescale products that the kit is based on， which speeds up the development process by showing a working example.

　　The contents of this kit will save many months of work， even for experienced powertrain engineers just looking to evaluate Freescale products. A system has been created based on a one-cylinder closed-loop engine controller using integrated technology while being cost-effective for the small engine market. Example software is provided that can be customized to run an actual engine that has electronic fuel injection. Documentation is provided to aid in going through the process of developing an application. Finally， information on modifying the design to support the adaptation of the small engine reference design to your application goals.

　　图5.参考设计板KIT912S812ECUEVM外形图

　　参考设计KIT912S812ECUEVM包括：

　　•Assembled and tested KIT912S812ECUEVM board in anti-static bag.

　　•ECU wire harness

　　•USB BDM Tool

　　•6-pin ribbon cable

　　•A-to-B USB cable

　　•Warranty card

图6.参考设计板KIT912S812ECUEVM建立图

图7.小型摩托车引擎控制系统框图

图8.参考设计板KIT912S812ECUEVM系统框图和系统负载

图9.参考设计板KIT912S812ECUEVM电路图(1)

图10.参考设计板KIT912S812ECUEVM电路图(2)

图11.参考设计板KIT912S812ECUEVM电路图(3)

图12.参考设计板KIT912S812ECUEVM电路图(4)

图13.参考设计板KIT912S812ECUEVM电路图(5)

图14.参考设计板KIT912S812ECUEVM PCB元件布局图:顶层

图15.参考设计板KIT912S812ECUEVM PCB元件布局图:底层

参考设计板KIT912S812ECUEVM材料清单: