Datasheet

Background Debug Module
MC9S12DP256 — Revision 1.1
Background Debug Module (BDM)
BDM Internal
Register Position
Register (BDMINR)
(
Read: All modes
Write: Never
REG15–REG11 — Internal register map position
These five bits show the state of the upper five bits of the base
address for the system’s relocatable register block. BDMINR is a
shadow of the INITRG register which maps the register block to any
2K byte space within the first 32K bytes of the 64K byte address
space.
Operation
The BDM receives and executes commands from a host via a single wire
serial interface. There are two types of BDM commands, namely,
hardware commands and firmware commands.
Hardware commands are used to read and write target system memory
locations and to enter active background debug mode (see BDM
Hardware Commands). Target system memory includes all memory that
is accessible by the CPU.
Firmware commands are used to read and write CPU resources and to
exit from active background debug mode (see Standard BDM Firmware
Commands). The CPU resources referred to are the accumulator (D), X
index register (X), Y index register (Y), stack pointer (SP), and program
counter (PC).
Address: $FF07
Bit 7 654321Bit 0
Read: REG15 REG14 REG13 REG12 REG11 0 0 0
Write:
Reset: 00000000
= Unimplemented
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
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