RX8804CE
Page - 22
ETM59E-05
3) AF (Alarm Flag) bit
When this flag bit value is already set to “0”, occurrence of an alarm interrupt event changes it to “1”. When this
flag bit value is “1”, its value is retained until a “0” is written to it.
Table 40 AF bit AF bit
AF
Data
Description
Write
0
The AF bit is cleared to zero to prepare for the next status detection
Clearing this bit to zero enables /INT low output to be canceled (/INT remains Hi-Z) when an
alarm interrupt event has occurred
1
AF bit is retained even AF is 0 or 1.
To retain AF bit, user can write 1.
Read
0
Alarm interrupt events are not detected.
1
Alarm interrupt events are detected.
(Result is retained until this bit is cleared to 0)
4) AIE (Alarm Interrupt Enable) bit
When an
alarm interrupt event occurs (when the AF bit value changes from “0”
to “1”), this bit's value specifies
whether an interrupt signal is generated (/INT status changes from Hi-Z to low) or is not generated (/INT status
remains Hi-Z).
Table 41 AIE bit
AIE
Data
Description
Write / Read
0
1) When an alarm interrupt event
occurs, an interrupt signal is not generated
or is canceled (/INT status remains Hi-Z).
2) When an alarm interrupt event occurs, the interrupt signal is canceled
(/INT status changes from low to Hi-Z).
Even when the AIE bit value is “0” another interrupt event may change the /INT
status to low (or may hold /INT =
”L”)
1
When an alarm interrupt event
occurs, an interrupt signal is generated (/INT
status changes from Hi-Z to low
).
When an alarm interrupt event occurs, low-level output from the /INT pin occurs
only when the AIE bit value is “1”. This value is retained (not automatically cleared)
until the AF bit is cleared to zero
8.5.3. Examples of Alarm Settings
1) Example of alarm settings when Day has been specified (and WADA bit
=
0)
Table 42 Alarm Setting ex.1
Day is specified
WADA bit = 0
Reg – A
Reg - 9
Reg - 8
bit
7
AE
bit
6
S
bit
5
F
bit
4
T
bit
3
W
bit
2
T
bit
1
M
bit
0
S
HOUR
Alarm
MIN
Alarm
Monday through Friday, at 7:00 AM
Minute value is ignored
0 0 1 1 1 1 1 0
07h
AE = 1
Every Saturday and Sunday, for 30 minutes
each hour
Hour value is ignored
0 1 0 0 0 0 0 1
AE = 1
30h
Every day, at 6:59 AM
0 1 1 1 1 1 1 1
18h
59h
1 X X X X X X X
X: Don't care