Programming Model

Table 29-3. BDM/Breakpoint Registers

DRc[4–0]

Register Name

Abbreviation

Initial State

Page

 

 

 

 

 

0x00

Configuration/status register

CSR

0x00010_0000

p. 29-10

 

 

 

 

 

0x01–0x05

Reserved

 

 

 

 

 

0x06

Address attribute trigger register

AATR

0x0000_0005

p. 29-8

 

 

 

 

 

0x07

Trigger definition register

TDR

0x0000_0000

p. 29-14

 

 

 

 

 

0x08

Program counter breakpoint register

PBR

p. 29-13

 

 

 

 

 

0x09

Program counter breakpoint mask register

PBMR

p. 29-13

 

 

 

 

 

0x0A–0x0B

Reserved

 

 

 

 

 

0x0C

Address breakpoint high register

ABHR

p. 29-9

 

 

 

 

 

0x0D

Address breakpoint low register

ABLR

p. 29-9

 

 

 

 

 

0x0E

Data breakpoint register

DBR

p. 29-12

 

 

 

 

 

0x0F

Data breakpoint mask register

DBMR

p. 29-12

 

 

 

 

 

NOTE:

Debug control registers can be written by the external development system or the CPU through the WDEBUG instruction.

CSR is write-only from the programming model. It can be read or written through the BDM port using the RDMREG and WDMREG commands.

29.4.1 Revision A Shared Debug Resources

In the Revision A implementation of the debug module, certain hardware structures are shared between BDM and breakpoint functionality as shown in Table 29-4.

Table 29-4. Rev. A Shared BDM/Breakpoint Hardware

Register

BDM Function

Breakpoint Function

 

 

 

AATR

Bus attributes for all memory commands

Attributes for address breakpoint

 

 

 

ABHR

Address for all memory commands

Address for address breakpoint

 

 

 

DBR

Data for all BDM write commands

Data for data breakpoint

 

 

 

Thus, loading a register to perform a specific function that shares hardware resources is destructive to the shared function. For example, a BDM command to access memory overwrites an address breakpoint in ABHR. A BDM write command overwrites the data breakpoint in DBR.

MOTOROLA

Chapter 29. Debug Support

29-7

Page 679
Image 679
Motorola MCF5281 Revision a Shared Debug Resources, BDM/Breakpoint Registers, Rev. a Shared BDM/Breakpoint Hardware