MC9RS08KB12/8/4/2（RS08KB）是Freescale 公司的超低成本的入门级8位MCU,具有容易使用，设计灵活性和性能。RS08KB集成了多种外设和高效的RS08内核，支持中断，改善系统性能和节省其它元件成本。 RS08KB有多达12KB闪存，256B RAM,高分辨率12路10位ADC,TPM,模块定时器和ACMP,以提供块速精密的检测和控制。目标应用在小家电，照明控制，低档热控制BLDC风扇，手持设备，电池充电器和玩具。本文介绍了MC9RS08KB12主要特性，方框图，以及DEMO9RS08KB12演示板主要特性和电路图。

    The MC9RS08KB12/8/4/2 （RS08KB） family includes ultra-low-cost, entry-level 8-bit MCUs that balance ease of use with design flexibility and performance. The RS08KB family has an integrated peripheral set which includes a highly efficient RS08 core that supports interrupt capability, helping to improve system performance and save additional components costs. The RS08KB family eases migration by offering multiple package and flash size options, along with pin compatibility with other 5V families as well as the CodeWarrior development tool to support other 8-bit families. The family is available in 20, 16 or 8-pin packages, and features up to 12 KB flash and 254B RAM, high-resolution 12-ch., 10-bit ADC, TPM, modulo timers and ACMP to provide fast, precise sensing and control.

    MC9RS08KB12主要特性：

    o 8-Bit RS08 Central Processor Unit （CPU）

    – Up to 20 MHz CPU at 1.8 V to 5.5 V across temperature range of –40℃ to 85℃

    – Subset of HC08 instruction set with added BGND instruction

    – Single Global interrupt vector

    o On-Chip Memory

    – Up to 12 KB flash read/program/erase over full operating voltage and temperature,12 KB/8 KB/4 KB/2 KB flash are optional

    – Up to 254-byte random-access memory （RAM）， 254-byte/126-byte RAM are optional

    – Security circuitry to prevent unauthorized access to flash contents

    o Power-Saving Modes

    – Wait mode — CPU shuts down; system clocks continue to run; full voltage regulation

    – Stop mode — CPU shuts down; system clocks are stopped; voltage regulator in standby

    – Wakeup from power-saving modes using RTI, KBI, ADC, ACMP, SCI and LVD

    o Clock Source Options

    – Oscillator （XOSC） — Loop-control Pierce oscillator; crystal or ceramic resonator range of 31.25 kHz to 39.0625 kHz or 1 MHz to 16 MHz

    – Internal Clock Source （ICS） — Internal clock source module containing a frequency-locked-loop （FLL） controlled by internal or external reference; precision trimming of internal reference allows 0.2% resolution and 2% deviation over temperature and voltage; supporting bus frequencies up to 10 MHz

    o System Protection

    – Watchdog computer operating properly （COP） reset with option to run from dedicated 1 kHz internal low power oscillator

    – Low-voltage detection with reset or interrupt

    – Illegal opcode detection with reset

    – Illegal address detection with reset

    – Flash-block protection

    o Development Support

    – Single-wire background debug interface

    – Breakpoint capability to allow single breakpoint setting during in-circuit debugging