RA8804 CE
Page - 12
ETM60E-02
4) VLF (Voltage Low Flag) bit
This flag bit indicates the retained status of clock operations or internal data. Its value change from
“0” to “1”
indicates a possible data loss or time data error due to a supply voltage drop. Once this flag bit's value is
“1”, its
value is retained until a
“0” is written to it.
After powering up from 0 V, make sure to set this bit's value to
“1”. Please confirm table in 8.11. Backup and
Recovery.
VLF
Data
Description
Write
0
The VLF bit is cleared to zero to prepare for the next status detection.
1
Invalid (writing a 1 will be ignored)!
Read
0
No supply voltage drops occurred.
1
Low voltage has been detected, so data loss might have occurred and time
information might be compromised.
All registers must be initialized.
(This setting is retained until a
“” is written to this bit.)
5) VDET (Voltage Detection Flag) bit
This flag bit indicates the status of temperature compensation. Its value changes from
“0” to “1” when the
temperature compensation function has stopped operation due to a supply voltage drop. Once this flag bit's value
is 1, its value is retained until a 0 is written to it.
After powering up from 0 V, make sure to set this bit's value to
“1”. Please confirm table in 8.11. Backup and
Recovery.
VDET
Data
Description
Write
0
The VDET bit is cleared to zero to prepare for the next low voltage detection.
1
Invalid (writing a 1 will be ignored)!
Read
0
Temperature compensation is normal.
1
Temperature compensation has been stopped.