Dealing With Keep-Alive Circuitry By Using The Custom Foreground Monitor - HP HP8648A Instruction Manual

Chapter 4: Connecting the Emulator to a Target System
Installing Emulator Features
If you get a "w>" prompt for a monitor address, you may have incorrectly
interlocked the monitor to the target system. If the monitor was correctly
interlocked, check to see if there is a timing problem with the target terminations
for the monitor address range.
If you get the "b>" prompt or something other than the "M>" prompt, suspect a
failure in monitor operation. These prompts may indicate problems with the clock
or reset signals. If the monitor is interlocked, it may also indicate that the target
system responded with a bus error for a monitor access.
Dealing with keep-alive circuitry by using the
custom foreground monitor
The foreground monitor will periodically service the internal 6833x watchdog
timer if it is enabled via the SIM registers, but you may have problems with other
keep-alive circuitry located in the target system. Because the foreground monitor
cycles are shown to the target system, bus cycle activity monitors should not be a
problem. Also, because interrupts can be serviced within a reasonable period of
time, any keep-alive circuits that depend on interrupts should not be a problem.
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3 Set up a trace to capture all MC6833x cycles. You must trace background
cycles in order to see foreground monitor operation.
tg any
tsto any
tck -ub
t
4 Execute the command: rst -m
This tells the emulator to release reset, but enter the monitor.
5 Verify that the emulator is in the monitor.
The prompt should be "M>", indicating correct operation in the monitor.
There is not much that can go wrong up to this point because everything
required has already been verified.