Motorola M68LC302CAF20VCT User Manual page 63

CAUTION:
M68ICS08RK In-Circuit Simulator — Rev. 1
MOTOROLA
(low) and keep it at +7.5 Vdc until after RST goes high. The
TGT-IRQ signal is allowed to control the IRQ signal when RST is
not asserted.
8. Make sure that external circuitry does not interfere with the monitor
mode communications. When connecting external circuitry to the
RKICS board, use only the target system connectors J1 and J3. This
ensures that the target system will not interfere with the communications
and setup of the MCU's monitor mode by allowing the RKICS to
disconnect some target system components during monitor mode entry.
9. Make sure that W2 (bus clock divisor) is jumpered correctly. W2 is
provided to allow the user to select whether the MCU bus clock is equal
to CGMXCLK/2 (W2 pins 2 and 3 jumpered, default setting) or
CGMXCLK/4 (W2 pins 1 and 2 jumpered). This jumper affects the
power-on baud rate in monitor mode. Currently, only 9600-baud serial
communications rate is supported for monitor mode by the simulation
and debugging software.
10. When connecting to a target system, observe the setting of W3 (target
RST direction). W3 is provided to allow the user to select whether the
target system can reset the MCU on the RKICS (jumper between pins 2
and 3) or whether the target system receives a reset signal from the
RKICS (jumper between pins 1 and 2). RST is not a bidirectional,
open-drain signal at the target connectors. Removing the jumper leaves
the RST-IN signal pulled up to +3.3 V (or the current MCU V
setting).
11. When connecting to a target system, observe the setting of W1 (target
V disconnect). W1 is provided to allow the user to select whether the
DD
RKICS powers the target system's MCU and external circuitry (W1
jumper on) or whether the target provides the power for its MCU and
circuitry (W1 jumper off). The target system V
RKICS operating voltage in either case.
Before powering up, remove the W1 jumper if the target system is powered by
a source other than the RKICS. Failure to remove the jumper in this case will
cause the two power supply outputs to be connected together, possibly causing
large currents to flow over the target cable. If the RKICS is to provide power to
the target system, ensure that the current drain on the target connector's V
pins is kept under 100 mA.
Technical Reference and Troubleshooting
Technical Reference and Troubleshooting
Troubleshooting the Start Up
must match the
DD
voltage
DD
DD
User's Manual
63