Motorola MVME187 User Manual

Page of 173
5-10
Using the 187Bug Debugger
5
Preserving the Debugger Operating 
Environment
This section explains how to avoid contaminating the operating 
environment of the debugger. Topics covered include:
187Bug Vector Table and workspace
Hardware functions
Exception vectors used by 187Bug
CPU/MPU registers
187Bug uses certain of the MVME187 onboard resources and may 
also use offboard system memory to contain temporary variables, 
exception vectors, etc. If you disturb resources upon which 187Bug 
depends, then the debugger may function unreliably or not at all. 
If your application enables translation through the Memory 
Management Units (MMUs), and utilizes resources of the debugger 
(e.g., system calls), your application must create the necessary 
translation tables for the debugger to have access to its various 
resources. The debugger honors the enabling of the MMUs; it does 
not disable translation. 
187Bug Vector Table and Workspace
The debugger and diagnostic firmware resides in the EPROMs. The 
first 64KB of RAM are also used by the debugger for storage of the 
Vector Table, executable code, variables, and stack.