PT7C4337_13 Datasheet, PDF (8/23 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

PT7C4337
Real-time Clock Module (I²C Bus)
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Function Description
Overview of Functions
Clock function
CPU can read or write data including the year (last two digits), month, date, day, hour, minute, and second. Any (two-digit) year
that is a multiple of 4 is treated as a leap year and calculated automatically as such until the year 2100.
Alarm function
This device has two alarm system (Alarm 1 and Alarm 2) that outputs interrupt signals from INTA or INTB to CPU when the date,
day of the week, hour, minute or second correspond to the setting. Each of them may output interrupt signal separately at a
specified time. The alarm is be selectable between on and off for matching alarm or repeating alarm.
Programmable square wave output
A square wave output enable bit controls square wave output at pin 7. Frequencies are selectable: 1, 4.096k, 8.192k, 32.768k Hz.
Interface with CPU
Data is read and written via the I²C bus interface using two signal lines: SCL (clock) and SDA (data).
Since the output of the I/O pin SDA is open drain, a pull-up resistor should be used on the circuit board if the CPU output I/O is
also open drain.
The SCL's maximum clock frequency is 400 kHz, which supports the I²C bus's high-speed mode.
Oscillator fail detect
When oscillator fail, PT7C4337 OSF bit will be set.
Oscillator enable/disable
Oscillator and time count chain can be enabled or disabled at the same time by /ETIME bit.
Registers
Allocation of registers
Addr.
(hex)^*1
Function
00 Seconds (00-59)
Bit 7
0
Bit 6
S40
Bit 5
S20
Register definition
Bit 4
Bit 3
S10
S8
01 Minutes (00-59)
0
M40
M20
M10
M8
02 Hours (00-23 / 01-12)
H20 or
0
12, /24
H10
H8
P, /A
03 Days of the week (01-07)
0
0
0
0
0
04 Dates (01-31)
0
0
D20
D10
D8
05 Months (01-12)
Century
0
0
MO10 MO8
06 Years (00-99)
07 Alarm 1: Seconds
Y80
Y40
Y20
Y10
Y8
A1M1^*2
S40
S20
S10
S8
Bit 2
S4
M4
H4
W4
D4
MO4
Y4
S4
Bit 1
S2
M2
H2
W2
D2
MO2
Y2
S2
Bit 0
S1
M1
H1
W1
D1
MO1
Y1
S1
2013-06-0002
PT0205-9 06/18/13
8