Motorola M68LC302CAF20VCT User Manual page 67

M68ICS08RK In-Circuit Simulator — Rev. 1
MOTOROLA
10. Make sure that the MCU can enter and remain in monitor mode. For this
to happen, the following conditions must occur:
a. At the rising edge of RST, the target MCU's IRQ pin must be at
V (+7.5 Vdc). Using a dual-trace oscilloscope, trigger channel 1
TST
on the rising edge of the MCU's RST pin and read the IRQ pin with
channel 2. Start the ICS08RKZ software as described in 2.4
Installing the Hardware and verify that the IRQ signal is
approximately +7.5 Vdc when RST rises.
b. At the rising edge of RST, PTA0, PTB0, PTB2, and PTB3 must be
held at logic values 1, 1, 0, and 0, respectively. The logic levels are
+3.3-volt CMOS logic levels (with the factory default setting of
+3.3 V on jumper J4). Using a dual-trace oscilloscope, trigger
channel 1 on the rising edge of RST and read the corresponding
MCU pin with channel 2. PTA0 is the serial data pin to and from
the host PC and should be around +3.3 Vdc at the rising edge of
RST. PTB0, PTB2, and PTB3 are controlled by analog switch U2
on the RKICS and should be approximately +3.3 V, 0 V, and 0 V,
respectively, at the rising edge of RST. After the rising edge of
RST, the MCU pins PTB0, PTB2, and PTB3 are connected (by the
RKICS) to the MON08 connector pins TGT-PTB0, TGT-PTB2,
and TGT-PTB3, respectively. The MCU's PTA0 pin is never
connected to the target pins because it is used for host
communication.
c. Either RST or IRQ must remain at +7.5 Vdc to hold the MCU in
monitor mode. The RKICS board has an IRQ lockout feature to
keep IRQ at 7.5 Vdc when the RST or RST-IN signal is asserted
(low) and to 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.
11. Make sure that the target circuitry does not interfere with the monitor
mode communications. When connecting target circuitry to the MCU, be
sure to connect the circuits through the RKICS by connecting to the
RST-OUT, RST-IN, TGT-IRQ, TGT-PTA0, TGT-PTB0, TGT-PTB2,
and TGT-PTB3 pins of the MON08 connector. These signals will be
connected by the RKICS to the corresponding pins of the MCU through
the corresponding MON08 connector pins — RST, IRQ, PTB0, PTB2,
Technical Reference and Troubleshooting
Technical Reference and Troubleshooting
Troubleshooting MON08 Mode
User's Manual
67