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Chapter 21 Background Debug Module (S12XBDMV2)
MC9S12XHZ512 Data Sheet, Rev. 1.03
758
Freescale Semiconductor
21.2
External Signal Description
A single-wire interface pin called the background debug interface (BKGD) pin is used to communicate
with the BDM system. During reset, this pin is a mode select input which selects between normal and
special modes of operation. After reset, this pin becomes the dedicated serial interface pin for the
background debug mode.
21.3
Memory Map and Register Definition
21.3.1
Module Memory Map
Table 21-1
shows the BDM memory map when BDM is active.
Table 21-1. BDM Memory Map
Global Address
Module
Size
(Bytes)
0x7FFF00–0x7FFF0B
BDM registers
12
0x7FFF0C–0x7FFF0E
BDM firmware ROM
3
0x7FFF0F
Family ID (part of BDM firmware ROM)
1
0x7FFF10–0x7FFFFF
BDM firmware ROM
240