SHANGHAI
BELLING
BL5362
Low Power Real-Time Clock (RTC)
GENERAL DESCRIPTION
The BL5362 is a CMOS type real-time clock,
which is connected to the CPU via two wires
and capable of serial transmission of clock to
the CPU. Since an oscillation circuit is driven
at a constant voltage, it undergoes fluctuations
of few voltage and consequently offers low
current consumption (TYP. 500nA @ 3.6V)
It also provides an oscillator halt sensing
function applicable for data validation at
power-on and other occasions. The product
also incorporates a time trimming circuit that
adjusts the clock with higher precision by
adjusting any errors in crystal oscillator
frequencies based on signals from the CPU.
The crystal oscillator may be selected from
32KHz or 32.768KHz types.
It adopts 8-pin SOP package.
FEATURES
Lowest supply current: 500nA TYP. @
3.6V
Connected to the CPU via only 2-wires
(MAX. 100KHz)
A clock counter (counting hours, minutes,
and seconds) and a calendar counter
(counting leap years, years, months, days,
and days of the week) in BCD codes
Oscillation halt sensing to judge internal
data validity
Clock output of 32.768KHz (32KHz)
(output controllable via a register)
Second digit adjustment by
±30
seconds
Automatic leap year recognition up to the
year 2099
12-hour or 24-hour time display selectable
High precision time trimming circuit
Oscillator of 32.768KHz or 32KHz may be
used
CMOS logic
Package: 8pin SOP or TSSOP
BL5362 Data Sheet
1
Shanghai Belling
BLOCK DIAGRAM
ORDERING INFORMATION
Type number
BL5362
BL5362T
Name
SOP8
TSSOP8
Package
Description
plastic small outline package;8 pins; body width 3.9mm
plastic thin shrink small outline package; 8 pins; body width 4.3mm
PIN CONFIGURATION
8PIN SOP
8PIN TSSOP
PIN DEFINITION
Pin No.
Symbol
1
CLK32
2
OSCOUT
3
OSCIN
4
GND
5
NC
6
SCL
7
SDA
8
VDD
BL5362
CLK32 1
OSCOUT
2
OSCIN 3
GND 4
8 VDD
7 SDA
6 SCL
5 NC
Definition
32KHz OUTPUT
Oscillator Circuit Output
Oscillator Circuit Input
Ground Power
-
Serial Clock Line
Serial Data Line
Voltage Power
Value
0~12V
0~1.5V
0~1.5V
0V
-
0~5.5V
0~5.5V
0~5.5V
BL5362T
CLK32 1
OSCOUT
2
OSCIN 3
GND 4
8 VDD
7 SDA
6 SCL
5 NC
IN/OUT
OUT
OUT
IN
POWER
-
IN
IN/OUT
POWER
2
BL5362 Data Sheet
Shanghai Belling
VDD and GND
BL5362
VDD
C1
GND
0.1u
+
C2
VDD
GND
Bypass Capacitance
OSCIN and OSCOUT
The VDD pin is connected to the positive power supply and
GND to the ground. To prevent the possibility of noise, when
rapidly changing signal took place on BL5362 pin, we have to
place a capacitance beside the BL5362. One possibility is to
place a bypass capacitance as close as to the BL5362. The
capacitance capacity of C2 could be determined per user’s
demand, which provides large current passing ability between
the pin and the ground.
These pins configure an oscillator circuit by connecting a crystal
oscillator between the OSCIN-OSCOUT pins. The diagram beside
shows the connection method of such crystal oscillator circuit. It’s
recommended to choose the right crystal oscillator parameter
referring to the supplier’s suggestion, since it does determine the
start-up reliability and oscillation stability provided by external
devices. The influence of the distributing capacitance should be
considered when choosing capacitance capacity in an oscillator
circuit. To minimize output distortion, both crystal oscillator and
capacitance should be installed as close to BL5362 pin as possible.
SCL and SDA
BL5362
OSCIN
OSCOUT
Crystal Oscillator
Connection with External
Capacitance
SCL and SDA are Serial Clock Line and Serial Data Line to chief line connector of interface,
relatively. SCL is used to input shift clock pulses to synchronize data input/output to and from the
SDA pin with this clock. SDA inputs and outputs written or read data in synchronization with shift
clock pulses from the SCL pin. Depend on different level of current, separate pull-up resistance can
be added to SCL and SDA on exterior circuit board.
CLK32
CLK32 could output 32.768KHz clock pulses (when 32.768KHz crystal is used). When power is
activated from 0V, it could output 32.768kHz clock pulses (when 32.768KHz crystal is used).
BL5362 Data Sheet
3
Shanghai Belling
FUNCTIONAL DESCRIPTIONS
Allocation of Internal Addresses
Internal
Contents
Address
EH
Control Register 1
FH
Control Register 2
0H
1H
2H
3H
4H
5H
6H
7H
Second Counter
Minute Counter
Hour Counter
Day of the Week Counter
Day Counter
Month Counter
Year Counter
Time Trimming Register
Function
Test Mode selected
Storing time display select, oscillator halt sensing
information
Counting and storing seconds in BCD codes
Counting and storing minutes in BCD codes
Counting and storing hours in BCD codes
Counting and storing days of the week in BCD codes
Counting and storing days in BCD codes
Counting and storing months in BCD codes
Counting and storing years in BCD codes
Storing adjusting parameter and external select control of
crystal oscillator
Calendar Counter
The BL5362 can exchange from year to
second (lower two bits) with CPU. When the
lower two bits of the year could be divided by
4, that year is leap year. It could automatically
recognize the year between 2000 and 2099 and
these data are stored separately in registers
from 0H to 6H.
High Precision time Trimming function
The BL5362 has an internal oscillation circuit
capacitance CGND and CVDD so that an
oscillation circuit may be configured simply
by externally connecting a crystal. The
BL5362 incorporates a time trimming circuit
(at internal address 7H) that adjusts gain or
loss of the clock from the CPU up to approx.
±
189ppm(
±
194ppm when 32.000KHz
crystal is used) by approximately 3ppm steps
to correct discrepancy in oscillation frequency.
Clock display is possible at much
higher precision than conventional
real-time clock while using a crystal
with
broader
fluctuation
in
precision.
Even seasonal frequency fluctuation
may be corrected by adjusting
seasonal clock error.
For those systems that have temperature
detection precision of clock, function may be
increased by correcting clock error according
to temperature fluctuations.
Control Unit
The control unit is a substantial part of the
BL5362, under which all functionalities of the
whole circuit is realized. The time display
select, as well as oscillation halt sensing
information are all sent out by the control
circuit.
Oscillation Halt Sensing
The oscillation halt sending function uses a
register (XSTP bit at internal address FH) to
store oscillation halt information. This
function may be used to determine if the
BL5362 supply power has been booted from
0V and if it has been backed up. This
function is useful for determining if clock
data is valid or invalid.
Clock Output
The BL5362 may output oscillation
frequency from CLK32 pin. This clock
output is set for output by default, which is
set to on or off by setting the register
(internal address FH bit CLEN). It can also
choose
different
crystal
oscillator
(32.768KHz or 32.000KHz) by setting the
register (internal address 7H at bit XSL),
and output clock pulses with two different
frequencies.
4
BL5362 Data Sheet
Shanghai Belling
REGISTERS
1. Clock Counter（at internal address 0-2H）
Time digit display (in BCD code)
Second digits: Range from 00 to 59 and carried to minute digits when incremented from 59
to 00.
Minute digits: Range from 00 to 59 and carried to hour digits when incremented from 59 to
00.
Hour digits: See descriptions on the⎯12/24 bit (Section 6). Carried to day and day-of-the
week digits when incremented from 11 p.m. to 12 a.m. or 23 to 00.
Any registered imaginary time should be replaced with correct time as carrying to such registered
imaginary time digits from lower-order ones cause the clock counter malfunction.
Second digit register (at internal address 0H)
D7
-
0
0
D6
S40
S40
Undefined
D5
S20
S20
Undefined
D4
S10
S10
Undefined
D3
S8
S8
Undefined
D2
S4
S4
Undefined
D1
S2
S2
Undefined
D0
S1
S1
Undefined
Operation
Write
Read
Default
Minute digit register (at internal address 1H)
D7
-
0
0
D6
M40
M40
Undefined
D5
M20
M20
Undefined
D4
M10
M10
Undefined
D3
M8
M8
Undefined
D2
M4
M4
Undefined
D1
M2
M2
Undefined
D0
M1
M1
Undefined
Operation
Write
Read
Default
Hour digit register (at internal address 2H)
D7
D6
D5
D4
D3
D2
D1
D0
Operation
-
-
H10
H8
H4
H2
H1
Write
H20 or P/⎯A
0
0
H10
H8
H4
H2
H1
Read
H20 or P/⎯A
0
0
Undefined
Undefined Undefined Undefined Undefined Undefined
Default
*Default means read value when XSTP bit is set to “1” by starting up from 0V, or supply voltage drop,
etc.
2. Day-of-the-week Counter (at internal address 3H)
Day-of-the-week digits are incremented by 1 when carried to 1-day digits.
Day-of-the-week digits display (incremented in septimal notation):
(W4,W2,W1) = (0,0,0)→(0,0,1)→……→(1,1,0)→(0,0,0)
The relation between days of the week and day-of-the-week digits is defined as:
Sunday=(0,0,0); Monday=(0,0,1);
……
; Saturday=(1,1,0).
(W4, W2, W1) should not be set to (1,1,1).
Operation
D7
D6
D5
D4
D3
D2
D1
D0
Write
-
-
-
-
-
W4
W2
W1
Read
0
0
0
0
0
W4
W2
W1
Undefined Undefined Undefined
Default
0
0
0
0
0
*The default means read value when XSTP bit is set to “1” by starting up from 0V, or supply voltage
drop, etc.
3. Calendar Counter (at internal address 4-6H)
The automatic calendar function provides the following calendar digit displays in BCD
code and could recognize the leap year.
Day digits:
Range from 1 to 31 (for January, March, May, July, August, October, and
December).
BL5362 Data Sheet
5
PCB设计
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