MC68HC908AP16CFB datasheet(153/440 Pages) MOTOROLA

153 / 440 page

MC68HC908AP Family — Rev. 2.5

Data Sheet

MOTOROLA

153

Data Sheet – MC68HC908AP Family

Section 10. Monitor ROM (MON)

10.1 Introduction

This section describes the monitor ROM (MON) and the monitor mode

entry methods. The monitor ROM allows complete testing of the MCU

through a single-wire interface with a host computer. Monitor mode entry

can be achieved without use of the higher test voltage, VTST, as long as

vector addresses $FFFE and $FFFF are blank, thus reducing the

hardware requirements for in-circuit programming.

In addition, to simplify user coding, routines are also stored in the

monitor ROM area for FLASH memory program /erase and EEPROM

emulation.

10.2 Features

Features of the monitor ROM include:

•

Normal user-mode pin functionality

•

One pin dedicated to serial communication between monitor ROM

and host computer

•

Standard mark/space non-return-to-zero (NRZ) communication

with host computer

•

Execution of code in RAM or FLASH

•

FLASH memory security feature1

•

FLASH memory programming interface

•

Enhanced PLL (phase-locked loop) option to allow use of external

32.768-kHz crystal to generate internal frequency of 2.4576 MHz

1. No security feature is absolutely secure. However, Motorola’s strategy is to make reading or

copying the FLASH difficult for unauthorized users.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MC68HC908AP16CFB Datasheet(PDF) 153 Page - Motorola, Inc