Motorola 700/800-Series User Manual

4-12

Using the 162Bug Debugger

As described in the Memory Requirements section of Chapter 3, the 
162Bug firmware needs 64KB of read/write memory to operate. 

With the exception of the first 1024-byte vector table area, you must 
be extremely careful not to use the above-mentioned memory areas 
for other purposes. 

Refer to the Memory Requirements section of Chapter 3 to determine 
how to dictate the location of the reserved memory areas. 

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If, for example, your program inadvertently wrote over the 
static variable area containing the serial communication 
parameters, these parameters would be lost, resulting in a 
loss of communication with the system console terminal. 

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If your program corrupts the system stack, then an incorrect 
value may be loaded into the processor Program Counter 
(PC), causing a system crash. 

1024-byte area 

A user program vector table area

1024-byte area 

An exception vector table for the debugger itself to use

Space for static variables, and initializes these static variables to 
predeÞned default values.

Space for the system stack, and initializes the system stack pointer to 
the top of this area.