PT7C4372A Datasheet, PDF (18/30 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

PT7C4372A/4372C
Real-time Clock Module (I²C Bus)
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Periodic Interrupt Function
Periodic interrupt output can be obtained via PT7C4372A/C: /INTA or /INTB pin. Select among five periodic-cycle settings: 2 Hz
(once per 0.5 seconds), 1 Hz (once per second), 1/60 Hz (once per minute), 1/3600 Hz (once per hour), or monthly (on the 1 st of
each month).
Select between two output waveforms for periodic interrupts: an ordinary pulse waveform (2 Hz or 1 Hz) or a waveform (every
second, minute, hour, or month) for CPU-level interrupts that can support CPU interrupts.
A polling function is also provided to enable monitoring of pin states via registers.
Related registers
Period interrupts output via PT7C4372A/C: /INTA, /INTB
Addr.
Function
Bit 7
Bit 6
Bit 5
E Control 1
AALE BALE
SL2
F Control 2
-
-
/12, 24
Bit 4
SL1
ADJ or
XSTP
Bit 3
TEST
/CLEN
Bit 2
Bit 1
CT2
CT1
CTFG ^AAFG
Bit 0
CT0
BAFG
 SL2, SL1
Interrupt output select bits. Two alarm pulses (Alarm_A and alarm_B), periodic interrupt output (INT), 32kHz clock pulses may
be output to the /INTA or /INTB pins selectively by SL1 and SL2.
SL2 SL1
Description
0
0 Output Alarm_A, Alarm_B, INT to the /INTA. Output 32kHz clock pulses to /INTB.
Default
0
1 Output Alarm_A, INT to the /INTA. Output 32kHz clock pulses, Alarm_B to /INTB.
1
0 Output Alarm_A, Alarm_B to the /INTA. Output 32kHz clock pulses, INT to /INTB.
1
1 Output Alarm_A to the /INTA. Output 32kHz clock pulses, Alarm_B, INT to /INTB.
 CTFG:
During a read operation, this bit indicates the /INTA or /INTB pin's periodic interrupt output status. This status can be set as OFF
by writing a "0" to this bit when /INTA or /INTB = "H".
CTFG Data
Description
Read
0 Periodic interrupt output OFF status; /INTA or /INTB= OFF (Hi-z) Read
1 Periodic interrupt output ON status; /INTA or /INTB= "L"
Default
Write
A "0" can be written only when the periodic interrupt is in level mode, at which time the
0 /INTA or /INTB pin is set to OFF (“H”) status. After a "0" is written, the value still becomes
"1" again at the next cycle.
Default
1 Setting prohibited
12-07-0001
PT0150-8 07/04/12
18