APPENDIX B LIST OF CAUTIONS
User’s Manual U18432EJ5V0UD
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(25/35)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
Because the interrupt request signal is used to clear the standby mode, if there is an
interrupt source with the interrupt request flag set and the interrupt mask flag reset,
the standby mode is immediately cleared if set. Thus, the STOP mode is reset to the
HALT mode immediately after execution of the STOP instruction and the system
returns to the operating mode as soon as the wait time set using the oscillation
stabilization time select register (OSTS) has elapsed.
p.688
To use the peripheral hardware that stops operation in the STOP mode, and the
peripheral hardware for which the clock that stops oscillating in the STOP mode after
the STOP mode is released, restart the peripheral hardware.
p.690
To stop the internal low-speed oscillation clock in the STOP mode, use an option
byte to stop the watchdog timer operation in the HALT/STOP mode (bit 0
(WDSTBYON) of 000C0H = 0), and then execute the STOP instruction.
p.690
Chapter
1
9
Soft
Standby
function
STOP mode
To shorten oscillation stabilization time after the STOP mode is released when the
CPU operates with the high-speed system clock (X1 oscillation), temporarily switch
the CPU clock to the internal high-speed oscillation clock before the execution of the
STOP instruction. Before changing the CPU clock from the internal high-speed
oscillation clock to the high-speed system clock (X1 oscillation) after the STOP mode
is released, check the oscillation stabilization time with the oscillation stabilization
time counter status register (OSTC).
p.690
For an external reset, input a low level for 10
μs or more to the RESET pin.
(If an external reset is effected upon power application, the period during which the
supply voltage is outside the operating range (VDD < 1.8 V) is not counted in the 10
μs. However, the low-level input may be continued before POC is released.)
p.695
During reset input, the X1 clock, XT1 clock, internal high-speed oscillation clock, and
internal low-speed oscillation clock stop oscillating. External main system clock input
becomes invalid.
p.695
Hard
When the STOP mode is released by a reset, the RAM contents in the STOP mode
are held during reset input. However, because SFR and 2nd SFR are initialized, the
port pins become high-impedance, except for P130, which is set to low-level output.
p.695
Block diagram of
reset function
An LVI circuit internal reset does not reset the LVI circuit.
p.696
Watchdog timer
overflow
A watchdog timer internal reset resets the watchdog timer.
p.697
Do not read data by a 1-bit memory manipulation instruction.
p.703
Chapter
2
0
Soft
Reset
function
RESF: Reset
control flag
register
When the LVI default start function (bit 0 (LVIOFF) of 000C1H = 0) is used, LVIRF
flag may become 1 from the beginning depending on the power-on waveform.
p.703
If the low-voltage detector (LVI) is set to ON by an option byte by default, the reset
signal is not released until the supply voltage (VDD) exceeds 2.07 V
±0.2 V.
pp.704,
705
If an internal reset signal is generated in the POC circuit, the reset control flag
register (RESF) is cleared to 00H.
p.704
Timing of
generation of
internal reset
signal (LVIOFF =
1)
Set the low-voltage detector by software after the reset status is released (see
CHAPTER 22 LOW-VOLTAGE DETECTOR).
p.706
Chapter
2
1
Soft
Power-on-
clear
circuit
Timing of
generation of
internal reset
signal (LVIOFF =
0)
Set the low-voltage detector by software after the reset status is released (see
CHAPTER 22 LOW-VOLTAGE DETECTOR).
p.707