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Chapter 4: Connecting the Emulator to a Target System
Plugging The Emulator Into A Target System
Selecting a clock source
The emulator is designed to support the two clock modes of MC6833x processors.
If your target system provides a system frequency oscillator, select external clock
in the emulator configuration. If your target system has a cyrstal and uses the clock
synthesizer inside the MC6833x processor, select internal emulation clock.
When the emulator is configured for external clock, the target system clock is
received on the EXTAL input to the MC6833x processor. The XTAL output from
the MC6833x is not connected to the target system because it is specified to be a no
connect in this mode. While /RESET is low, the MC6833x processor is
disconnected from the target system MODCK line and MODCK is pulled low at
the MC6833x processor. This instructs the MC6833x to use the oscillator signal as
CLKOUT. The V
power supply line from the target system is connected to
DDSYN
the MC6833x processor through an LC filter on the emulator board.
When the emulator is configured for internal clock, the MC6833x is connected to a
crystal oscillator circuit on the emulator board. The crystal frequency is 32.768
kHz for the MC68332 and others that use a crystal in the lower frequence range,
and 4.194304 MHz for the MC68336 and others that use a crystal in the higher
frequence range. While /RESET is low, the MC6833x processor is disconnected
from the target system MODCK line and MODCK is pulled high at the MC6833x
processor. This instructs the MC6833x to use its on-chip clock synthesizer to
generate CLKOUT.
Running the emulator configured like the
processor
To determine whether the loading and timing changes of the emulator impact your
target system, configure the emulator to work like the target system processor.
This procedure uses no emulation monitor and no emulation memory. For this test,
the only emulation feature that is operating is the emulation-bus analyzer. The
emulation-bus analyzer is passive, like a preprocessor.
This plug-in procedure uses the built-in terminal interface. Once your target
system is operating with the emulator, you should begin using one of the graphical
user interfaces.
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