DS1318 Maxim, DS1318 Datasheet - Page 12

• Manufacturer Part Number: DS1318
• Description: The DS1318 parallel-interface elapsed time counter (ETC) is a 44-bit counter that maintains the amount of time that the device operates from main and/or backup power or during an external event
• Manufacturer: Maxim

Bits 7 to 4: Periodic Rate Select (PRS3–PRS0). When
the oscillator is enabled (ENOSC = 1) the PF flag is set
at the rates determined by the following table:
Parallel-Interface Elapsed Time Counter
Periodic Flag Frequency When ENOSC = 1
12
PRS3 PRS2 PRS1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
BIT 7
PRS3
____________________________________________________________________
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
BIT 6
PRS2
PRS0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
(Once per 1.067 Minutes)
(Once per 0.8669 Weeks)
(Once per 1.138 Hours)
(Once per 1.318 Days)
(Once per 24.27 Days)
Periodic Flag Not Set
BIT 5
PRS1
PERIODIC FLAG
FREQUENCY
1/2097152Hz
1/524288Hz
1/65536Hz
1/4096Hz
4096Hz
2048Hz
1024Hz
1/64Hz
512Hz
256Hz
128Hz
8Hz
4Hz
2Hz
1Hz
BIT 4
PRS0
Bits 3 to 0: Square-Wave Rate Select (SRS3–SRS0).
When the oscillator is enabled (ENOSC = 1) and run-
ning, and the square-wave pin is enabled (SQWE = 1),
the SQW pin outputs a square-wave signal determined
by the SRS bits according to the following table:
Square-Wave Output Frequency When SQWE = 1,
ENOSC = 1
SRS3 SRS2 SRS1
BIT 3
SRS3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
BIT 2
SRS2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
SRS0
Control Register B (0Bh)
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
SQUARE-WAVE OUTPUT
BIT 1
SRS1
FREQUENCY (Hz)
32,768
8192
4096
2048
1024
512
256
128
0.5
64
32
16
8
4
2
1
BIT 0
SRS0