HP 68302 User Manual page 108

Chapter 4: Plugging the Emulator into Target Systems
Configuring the Emulator for In-Circuit Operation
this is not necessary. The 68302 SCR register contains a bit, which when set
will suspend the watchdog timer whenever the FRZ pin is asserted. This bit
is called "FRZW". You can simply modify your code to set that bit on startup
and the watchdog timer will automatically be suspended when you are in the
background monitor.
If you do choose to use the foreground monitor, you cannot take advantage of
the FRZW feature since the FRZ pin is only asserted in the background
monitor. Note that the FRZ1 and FRZ2 bits of the SCR can likewise be used
to suspend timer1 and timer2 during background operation.
Step 6. Set up the emulator for the foreground monitor
Skip this step if you have decided not to use the foreground monitor.
Here are the steps you should follow if you choose to use the foreground
monitor:
Choose an address for the monitor. Unlike the background monitor,
1
the foreground monitor resides in the same memory space as your
program (hence the term "foreground"). You must first select the
address where the monitor will reside. Here are some considerations:
- The monitor MUST reside in emulation memory. Note that when you
configure the emulator and answer the questions regarding the foreground
monitor the memory map will automatically be modified to include a block of
emulation RAM for the monitor.
- All monitor cycles ( both reads and writes ) WILL be seen by your target
system, therefore, you must choose an address that your target system will
"tolerate". For example, if your target has a range of memory that is decoded
for read-only accesses you should not locate the monitor there.
- You should not locate the monitor in area that your program may overwrite.
The monitor must be mapped to emulation RAM, so you must be careful to
not allow it to get overwritten.
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