PT7C4339 Datasheet, PDF (13/22 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

PT7C4339/4339C
Real-time Clock Module
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4.7. Alarm Function
Related register
Addr.
(hex)
Function
Bit 7
Bit 6
Bit 5
Register definition
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00 Seconds
0
S40
S20
S10
S8
S4
S2
S1
01 Minutes
02 Hours
03 Days of the week
0
M40
M20
M10
M8
M4
M2
M1
H20 or
0
12, /24
H10
H8
H4
H2
H1
A, /P
0
0
0
0
0
W4
W2
W1
04 Dates
0
0
D20
D10
D8
D4
D2
D1
07 Alarm 1: Seconds
A1M1
S40
S20
S10
S8
S4
S2
S1
08 Alarm 1: Minutes
09 Alarm 1: Hours
0A Alarm 1: Day, Date
0B Alarm 2: Minutes
0C Alarm 2: Hours
0D Alarm 2: Day, Date
0E Control
A1M2
M40
M20
M10
H20 or
A1M3 12, /24
H10
A, /P
Day,
0,
0,
A1M4
/Date
D20
D10
A2M2
M40
M20
M10
H20 or
A2M3 12, /24
H10
A, /P
Day,
0,
0,
A2M4
/Date
D20
D10
/EOSC
0
BBSQI RS2
M8
M4
M2
H8
H4
H2
0,
W4,
W2,
D8
D4
D2
M8
M4
M2
H8
H4
H2
0,
W4,
W2,
D8
D4
D2
RS1 INTCN A2IE
M1
H1
W1,
D1
M1
H1
W1,
D1
A1IE
0F Status
OSF
0
0
0
0
0
Note: Alarm function does not support different hour system adopted in time and alarm register.
A2F
A1F
The PT7C4339 contains two time-of-day/date alarms. The alarms can be programmed (by the INTCN bit of the control
register) to operate in two different modes - each alarm can drive a common interrupt output. Bit 7 of each of the time-of-day/date
alarm registers are mask bits.
When all of the mask bits for each alarm are logic 0, an alarm only occurs when the values in the timekeeping registers 00h ~
04h match the values stored in the time-of-day/date alarm registers. The alarms can also be programmed to repeat every second,
minute, hour, day, or date. Table3 and Table4 show the possible settings.
The Day, /Date bits (bit 6 of the alarm day/date registers) control whether the alarm value stored in bits 0 ~ 5 of that register
reflects the day of the week or the date of the month. If the bit is written to logic 0, the alarm is the result of a match with date of
the month. If the bit is written to logic 1, the alarm is the result of a match with day of the week.
When the PT7C4339 register values match alarm register settings, the corresponding alarm flag (A1F or A2F) bit is set to
logic 1. If the corresponding alarm interrupt enable (A1IE or A2IE) is also set to logic 1, the alarm condition activates one of the
interrupt output (SQW/INT) signals. The match is tested on the once-per-second update of the time and date registers.
2015-08-0008
PT0508-1 08/24/15
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