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3.2.1.1. Reset by a Power On Reset Circuit (without using a RESET_N pin)
After a supply voltage exceeds the release voltage of a Power On Reset (POR), internal reset is deasserted after
"Internal initialization time" is elapsed. Please increase a supply voltage goes up into an operating voltage range
before "Internal initialization time" is elapsed. The CPU operates after internal reset is released.
After a supply voltage exceeds the release voltage of a Power On Reset (POR), LVD continues to output reset
signal until supply voltage exceeds the LVD release voltage.
And internal reset has priority during the time of "Internal initialization time". When rising time of a supply
voltage beyond "Internal initialization time", please refer to "3.2.1.3. Continuation of reset by LVD".
For example, if the operating voltage of a circuit board is more than 2.7V, after Power On Reset released, increase
a supply voltage to 2.7V before "Internal initialization time" is elapsed. And if the operating voltage of a circuit
board is more than 4.5V, after Power On Reset released, increase a supply voltage to 4.5V before "Internal
initialization time" is elapsed.
Operating voltage range
LVD release
Voltage
(V
)
LVL0
PORF release
Voltage
(V
)
PREL
POR release
Voltage
(V
)
PREL
0V
RESET_N pin
LVD reset
Internal reset
Note: When you use only a Power On Reset Circuit without RESET_N pin, the RESET_N pin should
input "High" level or opened.
LVD detection release time(t
Internal initialization time(
Figure 3.1 The reset operation by a Power On Reset Circuit
Clock Control and Operation Mode
Power slope
(V
)
PON
)
VDDT2
t
)
IINIT
57 / 68
TXZ+ Family
TMPM4K Group(2)
DVDD5=DVDD5A=DVDD5B=AVDD5
DVDD5
CPU Operation start
2023-12-25
Rev. 3.0
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