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Fix:
Use the foreground monitor and include the necessary
modifications. Refer to "Step 7. If you use the 68302 built-in
DRAM refresh" for details on how to ensure proper DRAM
refresh.
PROBLEM: The emulator status line shows "M68302--Halted"
Cause:
A double-bus fault has occurred, or the target system has
asserted the HLT pin. This is almost always caused by a
double-bus fault. Most often a bus error or address error
exception fails to complete correctly because of an invalid stack
or vector table entry.
Fix:
Make sure you have a valid stack and valid vector table entries.
Refer to "Step 9. If emulator status shows HALTED" for
troubleshooting information.
PROBLEM: Incorrect data is read from target RAM or ROM.
Cause:
This is most often caused by a slow rising DTACK signal. The
DTACK signal is usually pulled high with a resistor. Any
resistor value above 1K ohms will usually result in some target
memory cycles that are terminated with 0 wait states regardless
of how the chip-select registers are programmed.
Fix:
Make sure that the pullup resistor on DTACK is no higher than
1K ohms. Refer to "Step 11. Check your DTACK pullup
resistor!" for more information.
Chapter 5: Plugging into a Target System
Configuring the Emulator for In-Circuit Operation
177
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