Freescale 公司的MC9S12XHY系列是16位微控制器，具有高性能的32位特性， CPU12XV1 CPU內核具有高達40MHz總線頻率，支持CAN和LIN/J2602通信，并提供多達4個步進馬達控制以及40x4 LCD驅動器，帶ECC特性的多達245KB片上閃存和8KB數據閃存，12KB片上SRAM等功能。目標用在低端儀表盤，汽車HVAC步進馬達以及汽車音頻系統。本文介紹了MC9S12XHY256主要特性，方框圖，以及DEMO9S12XHY256演示板主要特性和電路圖。
　　The MC9S12XHY family is an optimized， automotive， 16-bit microcontroller product line focused on low-cost and high-performance. This family is intended to bridge from low-end 16-bit microcontrollers， such as MC9S12HY family， to high performance 32-bit solutions. The MC9S12XHY family is targeted at the lower end of automotive instrument cluster applications， it includes support for CAN and LIN/J2602 communication and delivers typical cluster requirements such as stepper motor control with stepper stall detection （SSD） and LCD Driver.
　　The MC9S12XHY family delivers all the advantages and efficiencies of a 16-bit MCU while retaining the low cost， power consumption， EMC， and code-size efficiency advantages currently enjoyed by users of Freescale’s existing 8-bit and 16-bit MCU families. Like the MC9S12HY family， the MC9S12XHY family will run 16-bit wide accesses without wait states for all peripherals and memories. The MC9S12XHY family will be available in 100-pin LQFP and 112-pin LQFP package options and aims to maximize pin compatibility with the MC9S12HY family in the 100 LQFP. In addition to the I/O ports available in each module， further I/O ports are available with interrupt capability allowing wake-up from stop or wait modes.
　　MC9S12XHY256主要特性：
　　CPU12XV1 CPU core， with up to 40Mhz bus frequency
　　Up to 256 Kbyte on-chip flash with ECC and 8Kbyte data flash with ECC.
　　Up to 12Kbyte on-chip SRAM
　　Up to 40x4 LCD driver
　　Stepper Motor Controller with up to drivers for up to 4 motors， plus four Stepper Stall Detector modules （one for each motor）
　　Phase locked loop （IPLL） frequency multiplier with internal filter， supporting 4–16 MHz amplitude controlled Pierce oscillator
　　Pulse width modulation （PWM） module and Two timer modules （TIM0 and TIM1）
　　Up to 12-channel， 10-bit resolution successive approximation analog-to-digital converter （ATD）
　　serial peripheral interface （SPI） module and Inter-IC bus interface （IIC） module
　　Two serial communication interface （SCI） module supporting LIN communications
　　Two multi-scalable controller area network （MSCAN） module （supporting CAN protocol 2.0A/B）
　　On-chip voltage regulator （VREG） for regulation of input supply and all internal voltages
　　Autonomous periodic interrupt （API） and up to 25 key wakup inputs
　　MC9S12XHY256目標應用：
　　Low end instrument cluster
　　Automotive HVAC stepper motor based actuator control
　　Automotive Audio system
　　
　　圖1. MC9S12XHY系列方框圖