RA8900 SA / CE
Page - 12
ETM44E-01
VLF
Data Description
Write
0
The VLF bit is cleared to zero to prepare for the next status detection.
1
This bit is invalid after a "1" has been written to it.
Read
0
Data loss is not detected.
1
Data loss is detected. All registers must be initialized.
( This setting is retained until a "zero" 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 stop the
temperature compensation, such as 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.
When after powering up from 0 V this bit's value is "1".
VDET
Data Description
Write
0
The VDET bit is cleared to zero to prepare for the next low voltage detection.
1
The write access of "1" to this bit is invalid.
Read
0
Temperature compensation is normal.
1
Temperature compensation is stop detected.
8.2.7. Control register
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0F, 1F
Control Register
CSEL1
CSEL0
UIE
TIE
AIE
RESET
(Default)
(0)
(1)
(
)
(
)
(
)
(0)
(0)
(
)
1)
The default value is the value that is read (or is set internally) after powering up from 0 V.
2)
"o" indicates write-protected bits. A zero is always read from these bits.
3)
"
" indicates no default value has been defined.
This register is used to control interrupt event output from the /INT pin and the stop/start status of clock and
calendar operations.
1) CSEL0,1 ( Compensation interval Select 0, 1 ) bits
The combination of these two bits is used to set the temperature compensation interval.
CSEL0,1
CSEL1
(bit 7)
CSEL0
(bit 6)
Compensation interval
Write/Read
0 0 0.5
s
0 1 2.0
s
Default
1 0 10
s
1 1 30
s
2) UIE ( Update Interrupt Enable ) bit
When a time update interrupt event is generated (when the UF bit value changes from "0" to "1"), this bit's value
specifies if an interrupt signal is generated (/INT status changes from Hi-Z to low) or is not generated (/INT status
remains Hi-Z).
When a "1"
is written to this bit, an interrupt signal is generated (/INT status changes from Hi-Z to low) when an
interrupt event is generated.
When a "0"
is written to this bit, no interrupt signal is generated when an interrupt event occurs.