CHAPTER 20 RESET FUNCTION
User’s Manual U16896EJ2V0UD
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20.3 Register to Check Reset Source
(1) Reset source flag register (RESF)
The RESF register is a special register that can be written only by a combination of specific sequences (refer
to
3.4.7 Special registers
).
The RESF register indicates the source from which a reset signal is generated.
This register can be read or written in 8-bit or 1-bit units (however, only “0” can be written to this register).
RESET pin input or reset by the POC circuit (POCRES) clears this register to 00H. The default value differs if
reset is effected from a source other than the RESET pin.
WDT1RF
WDT2RF
0
1
Not generated
Generated
RESF
0
0
WDT2RF
0
0
CLMRF
LVIRF
After reset:
00H
Note
R/W Address: FFFFF888H
Reset signal from watchdog timer 2 (WDTRES2)
WDT1RF
0
1
Not generated
Generated
Reset signal from watchdog timer 1 (WDTRES1)
LVIRF
0
1
Not generated
Generated
Reset signal from low-voltage detector (LVIRES)
CLMRF
0
1
Not generated
Generated
Reset signal from clock monitor (CLMRES)
Note
This register is cleared to 00H when a reset is executed via the RESET pin or POC circuit.
When a reset is executed by the WDTRES1 signal, WDTRES2 signal, low-voltage detector (LVI), or
clock monitor (CLM), the reset flags of this register (WDT1RF, WDT2RF, CLMRF, and LVIRF bits) are
set (with the other sources retained).
Caution Only “0” can be written to each bit of this register. If writing “0” conflicts with setting the flag
(occurrence of reset), setting the flag takes precedence.