Datasheet

MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
MOTOROLA Monitor ROM (MON) 113
NON-DISCLOSURE AGREEMENT REQUIRED
Data Sheet — MC68HC908QY4
Section 9. Monitor ROM (MON)
9.1 Contents
9.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
9.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
9.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
9.4.1 Forced Monitor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
9.4.2 V
TST
Monitor Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120
9.4.3 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
9.4.4 Break Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
9.4.5 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
9.4.6 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
9.5 Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
9.2 Introduction
This section describes the monitor read-only memory (MON) and the
monitor mode entry methods. The monitor ROM allows complete testing
of the microcontroller unit (MCU) through a single-wire interface with a
host computer. Monitor mode entry can be achieved without use of the
higher test voltage, V
TST
, as long as vector addresses $FFFE and
$FFFF are blank, thus reducing the hardware requirements for in-circuit
programming.