mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 167

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 5
Background Debug Module (S12XBDMV2)
5.1
This section describes the functionality of the background debug module (BDM) sub-block of the
HCS12X core platform.
The background debug module (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.
The BDM has enhanced capability for maintaining synchronization between the target and host while
allowing more flexibility in clock rates. This includes a sync signal to determine the communication rate
and a handshake signal to indicate when an operation is complete. The system is backwards compatible to
the BDM of the S12 family with the following exceptions:
5.1.1
The BDM includes these distinctive features:
Freescale Semiconductor
Revision
Number
V02.00
V02.01
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•
•
•
•
•
•
•
•
•
•
•
TAGGO command no longer supported by BDM
External instruction tagging feature now part of DBG module
BDM register map and register content extended/modified
Global page access functionality
Enabled but not active out of reset in emulation modes (if modes available)
CLKSW bit set out of reset in emulation modes (if modes available).
Family ID readable from firmware ROM at global address 0x7FFF0F (value for HCS12X devices
is 0xC1)
Single-wire communication with host development system
Enhanced capability for allowing more flexibility in clock rates
SYNC command to determine communication rate
GO_UNTIL command
Hardware handshake protocol to increase the performance of the serial communication
Introduction
Revision Date
Features
14 May 2008
07 Mar 2006
Sections
Affected
S12XS Family Reference Manual, Rev. 1.10
Table 5-1. Revision History
- First version of S12XBDMV2
- Introduced standardized Revision History Table
Description of Changes
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