pcf8564a NXP Semiconductors, pcf8564a Datasheet - Page 14

• Manufacturer Part Number: pcf8564a
• Description: Real Time Clock And Calendar
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF8564A_1
Product data sheet
8.6.2 Register Hour_alarm
8.6.3 Register Day_alarm
8.6.4 Register Weekday_alarm
8.6.5 Alarm flag
Table 19.
[1]
Table 20.
[1]
Table 21.
[1]
By clearing the MSB of one or more of the alarm registers AE_x (Alarm Enable), the
corresponding alarm condition(s) are active. When an alarm occurs, AF is set to logic 1.
The asserted AF can be used to generate an interrupt (INT). The AF is cleared using the
interface.
The registers at addresses 09h through 0Ch contain alarm information. When one or
more of these registers is loaded with a valid minute, hour, day or weekday and its
corresponding Alarm Enable bit (AE_x) is logic 0, then that information is compared with
the current minute, hour, day and weekday. When all enabled comparisons first match, the
Alarm Flag (AF in register Control_2) is set to logic 1.
Bit
7
6
5 to 4 HOUR_ALARM
3 to 0
Bit
7
6
5 to 4 DAY_ALARM
3 to 0
Bit
7
6 to 3 -
2 to 0 WEEKDAY_ALARM 0 to 6
Default value.
Default value.
Default value.
Symbol
AE_H
-
Symbol
AE_D
-
Symbol
AE_W
Hour_alarm - hour alarm register (address 0Ah) bit description
Day_alarm - day alarm register (address 0Bh) bit description
Weekday_alarm - weekday alarm register (address 0Ch) bit description
Rev. 1 — 8 October 2009
Value
0
1
-
Value
0
1
-
0 to 2
0 to 9
Value
0
1
-
0 to 3
0 to 9
[1]
[1]
[1]
Place value Description
-
-
-
ten’s place
unit place
Place value Description
-
-
-
ten’s place
unit place
Description
weekday alarm is enabled
weekday alarm is disabled
unused
weekday alarm information coded in BCD format
hour alarm is enabled
hour alarm is disabled
unused
hour alarm information coded in BCD
format
day alarm is enabled
day alarm is disabled
unused
day alarm information coded in BCD
format
Real time clock and calendar
PCF8564A
© NXP B.V. 2009. All rights reserved.
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