Datasheet

Table Of Contents
MC9S12DP256 — Revision 1.1
Background Debug Module (BDM)
Background Debug Module (BDM)
Background Debug Module (BDM)
Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
Interface Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692
Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 698
Modes of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
Low-Power Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711
Interrupt Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711
Overview
The Background Debug Mode (BDM) sub-block is a single-wire,
background debug system implemented in on-chip hardware for minimal
CPU intervention. All interfacing with the BDM is done via the BKGD pin.
Features Single-wire communication with host development system
Active out of reset in special single-chip mode
Nine hardware commands using free cycles, if available, for
minimal CPU intervention
Hardware commands not requiring active BDM
15 firmware commands execute from the standard BDM firmware
lookup table
Instruction tagging capability
Software control of BDM operation during wait mode
Software selectable clocks
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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