Datasheet

MC68HC908GR8 — Rev 4.0 Technical Data
MOTOROLA Monitor ROM (MON) 189
Technical Data — MC68HC908GR8
Section 15. Monitor ROM (MON)
15.1 Contents
15.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
15.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189
15.4 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
15.5 Security. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202
15.2 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, V
TST
, as long as
vector addresses $FFFE and $FFFF are blank, thus reducing the
hardware requirements for in-circuit programming.
15.3 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
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
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