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5. Precautions to be Taken When Debugging5.1 Reset
The M34570T-MCU uses a 74AC14 for its RESET signal input buffer, so that its electrical
characteristics differ from those of the actual chip. Table 5.1 lists the RESET signal input
characteristics of the M34570T-MCU.
Table 5.1 RESET signal input characteristics
5.2 System Clock
Depending on the supply voltage and operation mode, use one of the following frequencies for the
system clock:
• Supply voltage 5V: 4.2MHz or less (medium-speed mode)
1.0MHz or less (high-speed mode)
• Supply voltage 3V: 4.2MHz or less (medium-speed mode)
2.0MHz or less (high-speed mode)
To change this clock frequency to suit that of the target system, use the oscillator circuit board OSC-2
(included) with the necessary parts attached.
For details about the oscillation circuit constants, consult your oscillator manufacturer.
5.3 Real-time Capability of Timer
The PC4504 and M34570T-MCU have their internal clock operating even during emulation, so that
the timer values keep changing.
Example: (1) When single-stepping the program
(2) When registers or internal RAM are referenced or modified
H-level threshold voltage
L-level threshold voltage
Hysteresis voltage
Item Symbol
VP
VN
VH
Voltage
VCC=3.0V
VCC=4.5V
VCC=5.5V
VCC=3.0V
VCC=4.5V
VCC=5.5V
VCC=3.0V
VCC=4.5V
VCC=5.5V
Maximum
2.2V
3.2V
3.9V
-
-
-
1.2V
1.4V
1.6V
Minimum
-
-
-
0.5V
0.9V
1.1V
0.3V
0.4V
0.5V