The R2043K/T is a CMOS real-time clock IC connected to the CPU by four signal lines, CE, SCLK, SI, SO, and
configured to perform serial transmission of time and calendar data to the CPU. The periodic interrupt circuit is
configured to generate interrupt signals with six selectable interrupts ranging from 0.5 seconds to 1 month. The
2 alarm interrupt circuits generate interrupt signals at preset times. As the oscillation circuit is driven under
constant voltage, fluctuation of the oscillator frequency due to supply voltage is small, and the time keeping
current is small (TYP. 0.45µA at 3V). The oscillation halt sensing circuit can be used to judge the validity of
internal data in such events as power-on; The supply voltage monitoring circuit is configured to record a drop in
supply voltage below two selectable supply voltage monitoring threshold settings. The 32.768kHz clock output
function (N-channel open drain output) is intended to output sub-clock pulses for the external microcomputer.
The oscillation adjustment circuit is intended to adjust time counts with high precision by correcting deviations in
the oscillation frequency of the crystal oscillator. Since the package for these ICs are TSSOP10G (4.0x2.9x1.0:
R2043T) or FFP12 (2.0x2.0x1.0: R2043K), high density mounting of ICs on boards is possible.
4-wire Serial Interface
R2043K/T
’04.04.23
FEATURES
Minimum Timekeeping supply volt age TYP:0.66 to 5.5v (Worst: 1.00V to 5.5v); VDD pin
Low power consumption 0.45µA TYP at VDD=3V (1.00µA MAX.)
Four signal lines (CE, SCLK, SI, and SO) required for connection to the CPU.
Time counters (counting hours, minutes, and seconds) and calendar counters (counting years, months, days,
and weeks) (in BCD format)
Interrupt circuit configured to generate interrupt signals (with interrupts ranging from 0.5 seconds to 1 month)
to the CPU and provided with an interrupt flag and an interrupt halt
2 alarm interrupt circuits (Alarm_W for week, hour, and minute alarm settings and Alarm_D for hour and
minute alarm settings)
With Power-on flag to prove that the power supply starts from 0V
32-kHz clock output pin (N-channel open drain output)
Supply voltage monitoring circuit with two supply voltage monitoring threshold settings
Automatic identification of leap years up to the year 2099
Selectable 12-hour and 24-hour mode settings
High precision oscillation adjustment circuit
Built-in oscillation stabilization capacitors (CG and CD)
Package TSSOP10G (4.0mm x 2.9mm x 1.0mm: R2043T) FFP12 (2.0mm x 2.0mm x 1.0mm: R2043K)
CMOS process
PIN CONFIGURATION
R2043T(TSSOP10G)
R2043K(FFP12)
OSCOUT
OSCIN
CE
10
9
8
7
VDD
OSCIN
OSCOUT
CE
/INTR VSS
/INTR
VSS
SI
32KOUT
SCLK
Rev.2.06 - 1 -
1
2
3
SO
4
SI
5 6
TOP VIEW
8
9
10
11
12
1
2
SO
SCL
TOP VIEW
7
VDD
6
(VSS)
5
(VSS)
4
3
32KOUT
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R2043K/T
BLOCK DIAGRAM
32KOUT
OSCIN
OSCOUT
/INTR
32kHz
OUTPUT
CONTROL
OSC
OSC
DETECT
DIVIDER
CORREC
-TION
INTERRUPT CONTROL
DIV
COMPARATOR_W
COMPARATOR_D
TIME COUNTER
(SEC,MIN,HOUR,WEEK,DAY,MONTH,YEAR)
ADDRESS
DECODER
SHIFT REGISTER
SELECTION GUIDE
Part Number is designated as follows:
R2043K-E2 ←Part Number ↑ ↑
R2043a-bb
Code Description
Designation of the package.
a
bb Designation of the taping type. Only E2 is available.
K: FFP12
T: TSSOP10G
ALARM_W REGISTER
(MIN,HOUR, WEEK)
ALARM_D REGISTER
(MIN,HOUR)
ADDRESS
REGISTER
POWER_ON
I/O
CONTROL
VDD
VOLTAGE
DETECT
RESET
VSS
SCLK
SI
SO
CE
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Rev.2.06 - 2 -
R2043K/T
PIN DESCRIPTION
Symbol Item Description
CE Chip enable
Input
SCLK Serial Clock
Input
SI Serial Input The SI pin is used to input data intended for writing in synchronization with
SO Serial Output The SO pin is used to output data intended for reading in synchronization
/INTR Interrupt
Output
32KOUT 32kHz Clock
Output
OSCIN
OSCOUT
VDD
VSS
(VSS) Please connect to ground line, or do not connect any lines.
Oscillation
Circuit
Input / Output
Positive/Negative
Power
Supply Input
The CE pin is used for interfacing with the CPU. Should be held high to
allow access to the CPU. Incorporates a pull-down resistor. Should be
held low or open when the CPU is powered off. Allows a maximum input
voltage of 5.5v regardless of supply voltage.
The SCLK pin is used to input clock pulses synchronizing the input and
output of data to and from the SI and SO pins. Allows a maximum input
voltage of 5.5v regardless of supply voltage.
the SCLK pin. CMOS input. Allows a maximum input voltage of 5.5v
regardless of supply voltage.
with the SCLK pin. CMOS output. If the CE pin is low, the SO pin goes to a
high impedance state.
The /INTR pin is used to output alarm interrupt (Alarm_W) and alarm
interrupt (Alarm_D) and output periodic interrupt signals to the CPU signals.
Disabled at power-on from 0V. N-channel open drain output. Allows a
maximum pull-up voltage of 5.5v regardless of supply voltage.
The 32KOUT pin is used to output 32.768-kHz clock pulses. The pin is
N-channel open drain output. However it cannot be pulled up over
VDD+0.3v.
The OSCIN and OSCOUT pins are used to connect the 32.768-kHz crystal
oscillator (with all other oscillation circuit components built into the
R2043K/T).
The VDD pin is connected to the power supply. The VSS pin is grounded.
Rev.2.05 - 3 -
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R2043K/T
ABSOLUTE MAXIMUM RATINGS
(VSS=0V)
Symbol Item Pin Name Description Unit
VDD Supply Voltage VDD -0.3 to +6.5 V
VI Input Voltage CE, SCLK, SI -0.3 to +6.5 V
Output Voltage 1 SO, 32KOUT -0.3 to VDD + 0.3 V VO
Output Voltage 2 /INTR -0.3 to +6.5 V
PD Power Dissipation
Topt Operating Temperature -40 to +85
Tstg Storage Temperature -55 to +125
Topt = 25°C
300 mW
°C
°C
RECOMMENDED OPERATING CONDITIONS
(VSS=0V, Topt=-40 to +85°C)
Symbol Item Pin Name Min, Typ. Max. Unit
Vaccess Supply Voltage Power supply voltage
for interfacing
with CPU
VCLK Time keeping Voltage
VCLKL Minimum Time keeping
Voltage
fXT Oscillation Frequency 32.768 kHz
*1) CGout is connected between OSCIN and VSS, CDout is connected between OSCOUT and VSS.
R2043K/T series incorporates the capacitors between OSCIN and VSS, between OSCOUT and VSS.
Then normally, CGout and CDout are not necessary. For more detail, see “P.28 Adjustment of Oscillation
frequency”
*2) Crystal oscillator: CL=6-9pF, R1=50KΩ
Symbol Item Pin Name Conditions Min. Typ. Max. Unit
VIH “H” Input Voltage 0.8x
VIL “L” Input Voltage
IOH “H” Output
Current
IOL1 /INTR 2.0
IOL2
IIL Input Leakage
RDNCE Pull-down Resistance CE 40 120 400
IOZ1 SO VO=5.5V or VSS
IOZ2 /INTR VO=5.5V
IOZ3
IDD Time Keeping Current VDD VDD=3V,
VDETH Supply Voltage
VDETL Supply Voltage
*1) For time keeping current when outputting 32.768kHz from the 32KOUT pin, see “P.43 Typical
Characteristics”. For time keeping current when CGOUT, CDOUT is not equal to 0pF, see “P.28
Adjustment of Oscillation frequency”.
“L” Output
Current
Current
Output Off-state
Current
Monitoring Voltage “H”
Monitoring Voltage “L”
CE,
SCLK, SI
SO VOH=VDD-0.5V -0.5 mA
SO,
32KOUT
SI, SCLK VI=5.5V or VSS
32KOUT VO=5.5V
VDD
VDD
VDD=1.7 to 5.5V
VOL=0.4V
VDD=5.5V
VDD=5.5V
VDD=5.5V
VDD=5.5V
CE= OPEN
Output = OPEN
32KOUT=OFF
CGout=CDout=0pF
*1)
Topt=-30 to +70°C
Topt=-30 to +70°C
VDD
-0.3 0.2x
0.5
-1.0 1.0
-1 1
-1 1
-1 1
1.45 1.60 1.75 V
1.15 1.30 1.45 V
5.5
VDD
0.45 1.00
V
mA
µA
kΩ
µA
µA
Rev.2.05 - 5 -
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R2043K/T
AC ELECTRICAL CHARACTERISTICS
Unless otherwise specified: VSS=0V,Topt=-40 to +85°C
Input and Output Conditions: VIH=0.8×VDD,VIL=0.2×VDD,VOH=0.8×VDD,VOL=0.2×VDD,CL=50pF
Symbol Item Condi-
tions
t
CE Set-up Time 400 ns
CES
t
CE Hold Time 400 ns
CEH
tCR CE Recovery Time 62
f
SCLK Clock Frequency 1.0 MHz
SCLK
t
SCLK Clock High Time 400 ns
CKH
t
SCLK Clock Low Time 400 ns
CKL
t
SCLK Set-up Time 200 ns
CKS
tRD Data Output Delay T ime 300 ns
tRZ Data Output Floating T ime 300 ns
t
Data Output Delay Time
CEZ
300 ns
After Falling of CE
tDS Input Data Set-up Time 200 ns
tDH Input Data Hold T i me 200 ns
t
t
CKH
CKL
VDD≥1.7V
Min. Typ. Max.
Unit
µs
CE
t
t
CES
CKS
SCLK
t
DS
t
DH
SI
SO
tRD
t
RD
t
RZ
*) For reading/writing timing, see “P.28 Adjustment of Oscillation frequency”.
t
CEH
tCR
t
CEZ
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Rev.2.06 - 6 -
PACKAGE DIMENSIONS
R2043K
9 7
R2043K/T
10
12
0.103
0.5
0.5
1PIN INDEX
2PIN INDEX
0.3±0.15
0.2±0.15
(BOTTOM VIEW)
6
0.05
4
3 1
0.35
2.0±0.1
0.35
0.25
1.0Max
0.17±0.1
0.27±0.15
2.0±0.1
unit: mm
Rev.2.05 - 7 -
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R2043K/T
M
R2043T
2.9±0.2
10
1
0.2±0.1
0.5
6
5
0.1
0.15
0 to 10
2.8±0.2
4.0±0.2
°
0.55±0.2
+0.1
0.13
-0.05
(0.75)
-0.05
+0.1
0.85±0.15
0.1
unit: mm
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Rev.2.06 - 8 -
R2043K/T
GENERAL DESCRIPTION
Interface with CPU
The R2043K/T is connected to the CPU by four signal lines CE (Chip Enable), SCLK (Serial Clock), SI (Serial
Input), and SO (Serial Output), through which it reads and writes data from and to the CPU. The CPU can be
accessed when the CE pin is held high. Access clock pulses have a maximum frequency of 1 MHz allowing
high-speed data transfer to the CPU.
Clock and Calendar Function
The R2043K/T reads and writes time data from and to the CPU in units ranging from seconds to the last two
digits of the calendar year. The calendar year will automatically be identified as a leap year when its last two
digits are a multiple of 4. Consequently, leap years up to the year 2099 can automatically be identified as such.
*) The year 2000 is a leap year while the year 2100 is not a leap year.
Alarm Function
The R2043K/T incorporates the alarm interrupt circuit configured to generate interrupt signals to the CPU at
preset times. The alarm interrupt circuit allows two types of alarm settings specified by the Alarm_W registers
and the Alarm_D registers. The Alarm_W registers allow week, hour, and minute alarm settings including
combinations of multiple day-of-week settings such as "Monday, Wednesday, and Friday" and "Saturday and
Sunday". The Alarm_D registers allow hour and minute alarm settings. The Alarm_W outputs from /INTR pin, and
the Alarm_D outputs also from /INTR pin. Each alarm function can be checked from the CPU by using a polling
function.
High-precision Oscillation Adjustment Function
The R2043K/T has built-in oscillation stabilization capacitors (CG and CD), which can be connected to an
external crystal oscillator to configure an oscillation circuit. Two kinds of accuracy for this function are
alternatives. To correct deviations in the oscillator frequency of the crystal, the oscillation adjustment circuit is
configured to allow correction of a time count gain or loss (up to ±1.5ppm or ±0.5ppm at 25°C) from the CPU.
The maximum range is approximately ±189ppm (or ±63ppm) in increments of approximately 3ppm (or 1ppm).
Such oscillation frequency adjustment in each system has the following advantages:
* Allows timekeeping with much higher precision than conventional RTCs while using a crystal oscillator
with a wide range of precision variations.
* Corrects seasonal frequency deviations through seasonal oscillation adjustment.
* Allows timekeeping with higher precision particularly with a temperature sensing function out of RTC,
through oscillation adjustment in tune with temperature fluctuations.
Power-on Reset, Oscillation Halt Sensing Function and Supply Voltage Monitoring Function
The R2043K/T incorporates an oscillation halt sensing circuit equipped with internal registers configured to
record any past oscillation halt.
Power on reset function reset the control resisters when the system is powered on from 0V. At the same time, the
fact is memorized to the resister as a flag, thereby identifying whether they are powered on from 0V or battery
backed-up.
The R2043K/T also incorporates a supply voltage monitoring circuit equipped with internal registers configured to
record any drop in supply voltage below a certain threshold value. Supply voltage monitoring threshold settings
can be selected between 1.6V and 1.3V through internal register settings. The sampling rate is normally 1s.
The oscillation halt sensing circuit and the power-on reset flag are configured to confirm the established
invalidation of time data in contrast to the supply voltage monitoring circuit intended to confirm the potential
invalidation of time data. Further, the supply voltage monitoring circuit can be applied to battery supply voltage
monitoring.
Periodic Interrupt Function
The R2043K/T incorporates the periodic interrupt circuit configured to generate periodic interrupt signals aside
from interrupt signals generated by the alarm interrupt circuit for output from the /INTR pin. Periodic interrupt
signals have five selectable frequency settings of 2 Hz (once per 0.5 seconds), 1 Hz (once per 1 second), 1/60
Hz (once per 1 minute), 1/3600 Hz (once per 1 hour), and monthly (the first day of every month). Further,
periodic interrupt signals also have two selectable waveforms, a normal pulse form (with a frequency of 2 Hz or 1
Hz) and special form adapted to interruption from the CPU in the level mode (with second, minute, hour, and
month interrupts). The condition of periodic interrupt signals can be monitored with using a polling function.
32kHz Clock Output
The R2043K/T incorporates a 32-kHz clock circuit configured to generate clock pulses with the oscillation
Rev.2.05 - 9 -
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R2043K/T
frequency of a 32.768kHz crystal oscillator for output from the 32KOUT pin. The 32-kHz clock output can be
disabled by certain register settings but cannot be disabled without manipulation of any two registers with
different addresses to prevent disabling in such events as the runaway of the CPU. The pin is N-channel open
drain output, however it cannot be pulled up over VDD+0.3v.
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Rev.2.06 - 10 -
R2043K/T
Address Mapping
Address Register Name D a t a
A3A2A1A0 D7 D6 D5 D4 D3 D2 D1 D0
Century Bit
6 0110 Year Counter Y80 Y40 Y20 Y10 Y8 Y4 Y2 Y1
7 0111 Oscillation Adjustment
Register *3)
8 1000 Alarm_W
(Minute Register)
9 1001 Alarm_W
(Hour Register)
A 1010 Alarm_W
(Day-of-week
Register)
B 1011 Alarm_D
(Minute Register)
C 1100 Alarm_D
(Hour Register)
D 1101 - - - - - - - E 1110 Control Register 1 *3) WALEDALE
F 1111 Control Register 2 *3) VDSLVDET/XST
Notes:
* 1) All the data listed above accept both reading and writing.
* 2) The data marked with "-" is invalid for writing and reset to 0 for reading.
* 3) PON is a power-on-reset flag.
When the PON bit is set to 1 in Control Register 2, all the bits are reset to 0 in Oscillation Adjustment
Register, Control Register 1 and Control Register 2 excluding the /XST bit.
* 4) When DEV=0, the oscillation adjustment circuit is configured to allow correction of a time count gain or
loss up to ±1.5ppm.
When DEV=1, the oscillation adjustment circuit is configured to allow correction of a time count gain or
loss up to or ±0.5ppm.
* 5) /XST is an oscillation halt sensing monitor bit.
Setting the /12⋅24 bit should precede writing time data
(3) /CLEN2 32kHz Clock Output Bit 2
/CLEN2 Description
0 Enabling the 32-kHz clock circuit (Default)
1 Disabling the 32-kHz clock circuit
Setting the /CLEN2 bit or the /CLEN1 bit (D3 in the control register 2) to 0, specifies generating clock pulses
with the oscillation frequency of the 32.768-kHz crystal oscillator for output from the 32KOUT pin.
Conversely, setting both the /CLEN1 and /CLEN2 bit to 1 disabling (”H”) such output.
(4) TEST T est Bit
TEST Description
0 Normal operation mode. (Default)
1 Test mode.
The TEST bit is used only for testing in the factory and should normally be set to 0.
/12⋅24
/12⋅24
of the Alarm_W registers and the Alarm_D registers).
of the Alarm_W registers and the Alarm_D registers)
Description
/CLEN2 TEST CT2 CT1 CT0 (For Writing)
/CLEN2 TEST CT2 CT1 CT0 (For Reading)
(Default)
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Rev.2.06 - 12 -
R2043K/T
A
(5) CT2, CT1, and CT0 Periodic Interrupt Selection Bits
* 1) Pulse Mode: 2-Hz and 1-Hz clock pulses are output in synchronization with the increment of the
second counter as illustrated in the timing chart below.
Description
Wave form
mode
*1)
*1)
*2)
*2)
*2)
*2)
Interrupt Cycle and Falling Timing
2Hz (Duty50%)
1Hz (Duty50%)
Once per 1 second (Synchronized with
second counter increment)
Once per 1 minute (at 00 seconds of
every minute)
Once per hour (at 00 minutes and 00
seconds of every hour)
Once per month (at 00 hours, 00
minutes,
and 00 seconds of first day of every
month)
In the pulse mode, the increment of the second counter is delayed by approximately 92 µs from the
* 2) Level Mode: Periodic interrupt signals are output with selectable interrupt cycle settings of 1 second, 1
CTFG Bit
/INTR Pin
falling edge of clock pulses. Consequently, time readings immediately after the falling edge of clock
pulses may appear to lag behind the time counts of the real-time clocks by approximately 1 second.
Rewriting the second counter will reset the other time counters of less than 1 second, driving the
/INTR pin low.
minute, 1 hour, and 1 month. The increment of the second counter is synchronized with the falling
edge of periodic interrupt signals. For example, periodic interrupt signals with an interrupt cycle
setting of 1 second are output in synchronization with the increment of the second counter as
illustrated in the timing chart below.
/INTR Pin
CTFG Bit
pprox. 92µs
(Increment of second counter)
Rewriting of the second counter
Setting CTFG bit to 0
(Increment of
second counter)
*1), *2) When the oscillation adjustment circuit is used, the interrupt cycle will fluctuate once per 20sec. or
60sec. as follows:
Pulse Mode: The “L” period of output pulses will increment or decrement by a maximum of ±3.784 ms. For
example, 1-Hz clock pulses will have a duty cycle of 50 ±0.3784%.
Level Mode: A periodic interrupt cycle of 1 second will increment or decrement by a maximum of ±3.784 ms.
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
(1) VDSL VDD Supply Voltage Monitoring Threshold Selection Bit
VDSL Description
0 Selecting the VDD supply voltage monitoring threshold setting of
1 Selecting the VDD supply voltage monitoring threshold setting of
The VDSL bit is intended to select the VDD supply voltage monitoring threshold settings.
(2) VDET Supply Voltage Monitoring Result Indication Bit
VDET Description
0 Indicating supply voltage above the supply voltage monitoring
1 Indicating supply voltage below the supply voltage monitoring
Once the VDET bit is set to 1, the supply voltage monitoring circuit will be disabled while the VDET bit will
hold the setting of 1. The VDET bit accepts only the writing of 0, which restarts the supply voltage
monitoring circuit. Conversely, setting the VDET bit to 1 causes no event.
(3) /XST Oscillation Halt Sensing Monitor Bit
/XST Description
0 Sensing a halt of oscillation
1 Sensing a normal condition of oscillation
The /XST accepts the reading and writing of 0 and 1. The /XST bit will be set to 0 when the oscillation halt
sensing. The /XST bit will hold 0 even after the restart of oscillation.
(4) PON Power-on-reset Flag Bit
PON Description
0 Normal condition
1 Detecting VDD power-on -reset (Default)
The PON bit is for sensing power-on reset condition.
* The PON bit will be set to 1 when VDD power-on from 0v. The PON bit will hold the setting of 1
even after power-on.
* When the PON bit is set to 1, all bits will be reset to 0, in the Oscillation Adjustment Register, Control
Register 1, and Control Register 2, except /XST and PON. As a result, /INTR pin stops outputting.
* The PON bit accepts only the writing of 0. Conversely, setting the PON bit to 1 causes no event.
(5) /CLEN1 32kHz Clock Output Bit 1
/CLEN1 Description
0 Enabling the 32-kHz clock circuit (Default)
1 Disabling the 32-kHz clock circuit
Setting the /CLEN1 bit or the /CLEN2 bit (D4 in the control register 1) to 0, specifies generating clock pulses
with the oscillation frequency of the 32.768-kHz crystal oscillator for output from the 32KOUT pin.
Conversely, setting both the /CLEN1 and /CLEN2 bit to 1 disabling (”H”) such output.
1 Periodic interrupt output = “L”
The CTFG bit is set to 1 when the periodic interrupt signals are output from the /INTR pin (“L”). The CTFG
bit accepts only the writing of 0 in the level mode, which disables (“H”) the /INTR pin until it is enabled (“L”)
again in the next interrupt cycle. Conversely, setting the CTFG bit to 1 causes no event.
(7) WAFG,DAFG Alarm_W Flag Bit and Alarm_D Flag Bit
WAFG,DAFG Description
0 Indicating a mismatch between current time and preset alarm time (Default)
1 Indicating a match between current time and preset alarm time
The WAFG and DAFG bits are valid only when the WALE and DALE have the setting of 1, which is caused
approximately 61µs after any match between current time and preset alarm time specified by the Alarm_W
registers and the Alarm_D registers. The WAFG (DAFG) bit accepts only the writing of 0. /INTR pin
outputs off (“H”) when this bit is set to 0. And /INTR pin outputs “L” again at the next preset alarm time.
Conversely, setting the WAFG and DAFG bits to 1 causes no event. The WAFG and DAFG bits will have
the reading of 0 when the alarm interrupt circuit is disabled with the WALE and DALE bits set to 0. The
settings of the WAFG and DAFG bits are synchronized with the output of the /INTR pin as shown in the
timing chart below.
pprox. 61µs
pprox. 61µs
WAFG(DAFG) Bit
/INTR Pin
(Match between
current time and
preset alarm time)
Writing of 0 to
WAFG(DAFG) bit
(Match between
current time and
preset alarm time)
(Match between
current time and
preset alarm time)
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
* Time digit display (BCD format) as follows: The second digits range from 00 to 59 and are carried to the minute digit in transition from 59 to 00.
The minute digits range from 00 to 59 and are carried to the hour digits in transition from 59 to 00.
The hour digits range as shown in "P12 Control Register 1 (ADDRESS Eh) (2) /12⋅24: /12-24-hour
* Any writing to the second counter resets divider units of less than 1 second.
* Any carry from lower digits with the writing of non-existent time may cause the time counters to
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
* The day-of-week counter is incremented by 1 when the day-of-week digits are carried to the
* Day-of-week display (incremented in septimal notation):
* Correspondences between days of the week and the day-of-week digits are user-definable
(e.g. Sunday = 0, 0, 0)
* The writing of (1, 1, 1) to (W4, W2, W1) is prohibited except when days of the week are unused.
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
* The calendar counters are configured to display the calendar digits in BCD format by using the
The day-of-month digits (D20 to D1) range from 1 to 31 for January, March, May, July, August,
The year digits (Y80 to Y1) range from 00 to 99 (00, 04, 08, …, 92, and 96 in leap years) and are
The /19⋅20 digits cycle between 0 and 1 in reversion from 99 to 00 in the year digits.
* Any carry from lower digits with the writing of non-existent calendar data may cause the calendar
Oscillation Adjustment Register (Address 7h)
D7 D6 D5 D4 D3 D2 D1 D0
DEV F6 F5 F4 F3 F2 F1 F0 (For Writing)
DEV F6 F5 F4 F3 F2 F1 F0 (For Reading)
0 0 0 0 0 0 0 0 Default Settings *)
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
DEV bit
When DEV is set to 0, the Oscillation Adjustment Circuit operates 00, 20, 40 seconds.
When DEV is set to 1, the Oscillation Adjustment Circuit operates 00 seconds.
F6 to F0 bits
The Oscillation Adjustment Circuit is configured to change time counts of 1 second on the basis of the
automatic calendar function as follows:
October, and December; from 1 to 30 for April, June, September, and November; from 1 to 29 for
February in leap years; from 1 to 28 for February in ordinary years. The day-of-month digits are
carried to the month digits in reversion from the last day of the month to 1. The month digits (MO10
to MO1) range from 1 to 12 and are carried to the year digits in reversion from 12 to 1.
carried to the /19⋅20 digits in reversion from 99 to 00.
counters to malfunction. Therefore, such incorrect writing should be replaced with the writing of
existent calendar data.
settings of the Oscillation Adjustment Register at the timing set by DEV.
* The Oscillation Adjustment Circuit will not operate with the same timing (00, 20, or 40 seconds)
as the timing of writing to the Oscillation Adjustment Register.
* The F6 bit setting of 0 causes an increment of time counts by ((F5, F4, F3, F2, F1, F0) - 1) x 2.
The F6 bit setting of 1 causes a decrement of time counts by ((/F5, /F4, /F3, /F2, /F1, /F0) + 1) x 2.
The settings of "*, 0, 0, 0, 0, 0, *" ("*" representing either "0" or "1") in the F6, F5, F4, F3, F2, F1, and
F0
bits cause neither an increment nor decrement of time counts.
Example:
If (DEV, F6, F5, F4, F3, F2, F1, F0) is set to (0, 0, 0, 0, 0, 1, 1, 1), when the second digits read 00, 20,
or 40, an increment of the current time counts of 32768 + (7 - 1) x 2 to 32780 (a current time count
loss).
If (DEV, F6, F5, F4, F3, F2, F1, F0) is set to (0, 0, 0, 0, 0, 0, 0, 1), when the second digits read 00, 20,
40, neither an increment nor a decrement of the current time counts of 32768.
If (DEV, F6, F5, F4, F3, F2, F1, F0) is set to (1, 1, 1, 1, 1, 1, 1, 0), when the second digits read 00, a
decrement of the current time counts of 32768 + (- 2) x 2 to 32764 (a current time count gain).
An increase of two clock pulses once per 20 seconds causes a time count loss of approximately 3
ppm (2 / (32768 x 20 = 3.051 ppm). Conversely, a decrease of two clock pulses once per 20
seconds causes a time count gain of 3 ppm. Consequently, when DEV is set to “0”, deviations in
time counts can be corrected with a precision of ±1.5 ppm. In the same way, when DEV is set to “1”,
deviations in time counts can be corrected with a precision of ±0.5 ppm. Note that the oscillation
adjustment circuit is configured to correct deviations in time counts and not the oscillation frequency
of the 32.768-kHz clock pulses. For further details, see "P31 Oscillation Adjustment Circuit".
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
* The D5 bit of the Alarm_W Hour Register represents WP/A when the 12-hour mode is selected (0 for
* The Alarm_W Registers should not have any non-existent alarm time settings.
(Note that any mismatch between current time and preset alarm time specified by the Alarm_W registers
* When the 12-hour mode is selected, the hour digits read 12 and 32 for 0 a.m. and 0 p.m., respectively.
* WW0 to WW6 correspond to W4, W2, and W1 of the day-of-week counter with settings ranging from
* WW0 to WW6 with respective settings of 0 disable the outputs of the Alarm_W Registers.
Default Settings *)
*) Default settings: Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0v.
* The D5 bit represents DP/A when the 12-hour mode is selected (0 for a.m. and 1 for p.m.) and DH20
when the 24-hour mode is selected (tens in the hour digits).
* The Alarm_D registers should not have any non-existent alarm time settings.
(Note that any mismatch between current time and preset alarm time specified by the Alarm_D registers
may disable the alarm interrupt circuit.)
* When the 12-hour mode is selected, the hour digits read 12 and 32 for 0a.m. and 0p.m., respectively.
(See "P12 Control Register 1 (ADDRESS Eh) (2) /12⋅24: 12-/24-hour Mode Selection Bit")
12345
Rev.2.06 - 20 -
R2043K/T
K
r
Interfacing with the CPU
DA TA TRANSFER FORMATS
(1) Timing Between CE Pin Transition and Data Input / Output
The R2043K/T adopts a 4-wire serial interface by which they use the CE (Chip Enable), SCLK (Serial Clock), SI
(Serial Input), and SO (Serial Output) pins to receive and send data to and from the CPU. The 4-wire serial
interface provides two types of input/output timings with which the SO pin output and the SI pin input are
synchronized with the rising or falling edges of the SCLK pin input, respectively, and vice versa. The R2043K/T
is configured to select either one of two different input/output timings depending on the level of the SCLK pin in
the low to high transition of the CE pin. Namely, when the SCLK pin is held low in the low to high transition of
the CE pin, the models will select the timing with which the SO pin output is synchronized with the rising edge of
the SCLK pin input, and the SI pin input is synchronized with the falling edge of the SCLK pin input, as illustrated
in the timing chart below.
Conversely, when the SCLK pin is held high in the low to high transition of the CE pin, the models will select the
timing with which the SO pin output is synchronized with the falling edge of the SCLK pin input, and the SI pin
input is synchronized with the rising edge of the SCLK pin input, as illustrated in the timing chart below.
CE
SCLK
SI
SO
CE
t
CES
t
CES
tDS
tDH
t
RD
SCLK
tDS
tDH
t
SI
SO
RD
(2) Data Transfer Formats
Data transfer is commenced in the low to high transition of the CE pin input and completed in its high to low
transition. Data transfer is conducted serially in multiple units of 1 byte (8 bits). The former 4 bits are used to
specify in the Address Pointer a head address with which data transfer is to be commenced from the host. The
latter 4 bits are used to select either reading data transfer or writing data transfer, and to set the Transfer Format
Register to specify an appropriate data transfer format. All data transfer formats are designed to transfer the
most significant bit (MSB) first.
SCL
CE
SI
SO
A1 A0 C3C2C1C0
A2
A3
Setting
the Address Pointe
6
75823123 1 4
Setting the Transfer
Format Register
D7D6D3 D2 D1D0
Writing data transfer
D7D6D3 D2 D1D0
Reading data transfer
Two types of dat a transfer formats are available for reading data transfer and writing data transfer each.
12345
Rev.2.05 - 21 -
R2043K/T
A
A
A
Writing Data Transfer Formats
(1) 1-byte Writing Data Transfer Format
The first type of writing data transfer format is designed to transfer 1-byte data at a time and can be selected by
specifying in the address pointer a head address with which writing data transfer is to be commenced and then
writing the setting of 8h to the transfer format register. This 1-byte writing data transfer can be completed by
driving the CE pin low or continued by specifying a new head address in the address pointer and setting the data
transfer format.
Example of 1-byte Wr i t ing Data Transfer (For Writing Data to Addresses Fh and 7h)
CE
SI
11
010 011
DataData
0110 0 01 1
SO
Specifying Fh
in the
ddress
Pointer
Setting 8h in
the Transfer
Format
Register
Data transfer from the host
Writing data to
address Fh
Specifying 7h
in the
ddress
Pointer
Setting 8h in
the Transfer
Format
Register
Writing data to
address 7h
Data transfer from the RTCs
(2) Burst Writing Data Transfer Format
The second type of writing data transfer format is designed to transfer a sequence of data serially and can be
selected by specifying in the address pointer a head address with which writing data transfer is to be
commenced and then writing the setting of 0h to the transfer format register. The address pointer is
incremented for each transfer of 1-byte data and cycled from Fh to 0h. This burst writing data transfer can be
completed by driving the CE pin low.
Example of Burst Writing Data Tr ansf er ( For Writ ing Data to Addresses Eh, Fh, and 0h)
CE
SI
10
000 011
Data
Data
Data
SO
Specifying Eh
in the
ddress
Pointer
Setting 0h in
the Transfer
Format
Register
Writing data to
address Eh
Writing data to
address Fh
Data transfer from the hostData transfer from the RTCs
12345
Rev.2.06 - 22 -
Writing data to
address 0h
R2043K/T
A
A
A
Reading Data Transfer Formats
(1) 1-byte Reading Data Transfer Format
The first type of reading data transfer format is designed to transfer 1-byte data at a time and can be selected by
specifying in the Address Pointer a head address with which reading data transfer is to be commenced and then
the setting of writing Ch to the Transfer Format Register. This 1-byte reading data transfer can be completed by
driving the CE pin low or continued by specifying a new head address in the Address Pointer and selecting this
type of reading data T ransfer Format.
Example of 1-byte Reading Data Transfer (For Readi ng Dat a f r om Addr esses Eh and 2h)
CE
SI
SO
10
Specifying Eh
in the
ddress
Pointer
110 0110101 0 00 1
DataData
Setting Ch in
the Transfer
Format
Register
Reading data from
address Eh
Data transfer from the hostData transfer from the RTCs
Specifying 2h
in the
ddress
Pointer
Setting Ch in
the Transfer
Format
Register
Reading data from
address 2h
(2) Burst Reading Data Transfer Format
The second type of reading data transfer format is designed to transfer a sequence of data serially and can be
selected by specifying in the address pointer a head address with which reading data transfer is to be
commenced and then writing the setting of 4h to the transfer format register. The address pointer is
incremented for each transfer of 1-byte data and cycled from Fh to 0h. This burst reading data transfer can be
completed by driving the CE pin low.
Example of Burst Reading Data Transfer (For Reading Data from Addresses Fh, 0h, and 1h)
CE
SI
11
100 011
SO
Specifying Fh
in the
ddress
Pointer
Setting 4h in
the Transfer
Format
Register
Data transfer from the hostData transfer from the RTCs
DATA
Reading data from
address Fh
DATA
Reading data from
address 0h
Rev.2.05 - 23 -
DATA
Reading data from
address 1h
12345
R2043K/T
A
A
(3) Combination of 1-byte Reading and writing Data Transfer Formats
The 1-byte reading and writing data transfer formats can be combined together and further followed by any other
data transfer format.
Example of Reading Modify Writing Data Tr ansf er
(For Reading and Writing Data fr om and t o Addr ess Fh)
CE
DATASI
Writing data to
address Fh
SO
11
Specifying Fh
in the
ddress
Pointer
110 0111110 0 01 1
DATA
Setting Ch in
the Transfer
Format
Register
Reading data from
address Fh
Data transfer from the hostData transfer from the RTCs
Specifying Fh
in the
ddress
Pointer
Setting 8h in
the Transfer
Format
Register
The reading and writing data transfer formats correspond to the settings in the transfer format register as shown
in the table below.
1 Byte Burst
Writing data
transfer
Reading data
transfer
8h
(1,0,0,0)
Ch
(1,1,0,0)
0h
(0,0,0,0)
4h
(0,1,0,0)
12345
Rev.2.06 - 24 -
R2043K/T
Considerations in Reading and Writing Time Data under special condition
Any carry to the second digits in the process of reading or writing time data may cause reading or writing
erroneous time data. For example, suppose a carry out of 13:59:59 into 14:00:00 occurs in the process of
reading time data in the middle of shifting from the minute digits to the hour digits. At this moment, the second
digits, the minute digits, and the hour digits read 59 seconds, 59 minutes, and 14 hours, respectively (indicating
14:59:59) to cause the reading of time data deviating from actual time virtually 1 hour. A similar error also
occurs in writing time data. To prevent such errors in reading and writing time data, the R2043K/T has the
function of temporarily locking any carry to the second digits during the high interval of the CE pin and unlocking
such a carry in its high to low transition. Note that a carry to the second digits can be locked for only 1 second,
during which time the CE pin should be driven low.
Actual time
CE
Time counts
within RTC
The effective use of this function requires the following considerations in reading and writing time data:
(1) Hold the CE pin high in each session of reading or writing time data.
(2) Ensure that the high interval of the CE pin lasts within 1 second. Should there be any possibility of the host
going down in the process of reading or writing time data, make arrangements in the peripheral circuitry as to
drive the CE pin low or open at the moment that the host actually goes down.
(3) Leave a time span of 31µs or more from the low to high transition of the CE pin to the start of access to
addresses 0h to 6h in order that any ongoing carry of the time digits may be completed within this time span.
(4) Leave a time span of 62µs or more from the high to low transition of the CE pin to its low to high transition in
order that any ongoing carry of the time digits during the high interval of the CE pin may be adjusted within this
time span.
The considerations listed in (1), (3), and (4) above are not required when the process of reading or writing time
data is obviously free from any carry of the time digits.
(e.g. reading or writing time data in synchronization with the periodic interrupt function in the level mode or the
alarm interrupt function).
Good and bad examples of reading and writing time data are illustrated on the next page.
13:59:59 14:00:00 14:00:01
Max.62µs
13:59:59
14:00:00
14:00:01
Rev.2.05 - 25 -
12345
R2043K/T
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
Good Example
CE
Time span of 31µs or more
ny address other than addresses 0h to 6h
permits of immediate reading or writing without
requiring a time span of 31 µs.
SI
SO
F4h
ddress Pointer
= Fh
Transfer Format
Register = 4h
DATA
Reading from
ddress Fh
(control2)
DATA
Reading from
ddress 0h
(sec.)
DATA
Reading from
ddress 1h
(min.)
DATA
Reading from
ddress 2h
(hr.)
Bad Example (1)
(Where the CE pin is once driven low in the process of reading time data)
31µs or more
31µs or more
CE
SI
SO
0Ch
ddress Pointer
= 0h
Transfer Format
Register = Ch
Data
Reading from
ddress 0h
(sec.)
14h
ddress Pointer
= 1h
Transfer Format
Register = 4h
Data
Reading from
ddress 1h
(min.)
Data
Reading from
ddress 2h
(hr.)
Bad Example (2)
(Where a time span of less than 31µs is left until the start of the process of writing time data)
Time span of less than 31µs
CE
SI
F0h
Data Data Data Data
SO
Writing to
ddress 0h
(sec.)
Writing to
ddress 1h
(min.)
Writing to
ddress 2h
(hr.)
Bad Example (3)
ddress Pointer
= Fh
Transfer Format
Register = 0h
Writing to
ddress Fh
(contorl2)
(Where a time span of less than 61µs is left between the adjacent processes of reading time data)
Less than 62µs
CE
SI
SO
0Ch
0Ch
Data
ddress Pointer
= 0h
Transfer Format
Register = Ch
Reading from
ddress 0h
(sec.)
Data transfer from the host
Data
0Ch
Data
ddress Pointer
= 0h
Transfer Format
Register = Ch
Reading from
(sec.)
ddress 0h
Data transfer from RTCs
12345
Rev.2.06 - 26 -
Configuration of Oscillation Circuit and Correction of Time Count Deviations
Configuration of Oscillation Circuit
Typical externally-equipped element
X’tal : 32.768kHz
Oscillator
Circuit
CG
CD
OSCIN
OSCOUT
32kHz
A
(R1=50kΩ typ)
(CL=6pF to 9pF)
Standard values of internal elements
CG,CD 10pF typ
R2043K/T
The oscillation circuit is driven at a constant voltage of approximately 1.1v relative to the level of the VSS pin
input. As such, it is configured to generate an oscillating waveform with a peak-to-peak voltage on the order of
1.1v on the positive side of the VSS pin input.
< Considerations in Handling Crystal Oscillators >
Generally, crystal oscillators have basic characteristics including an equivalent series resistance (R1) indicating
the ease of their oscillation and a load capacitance (CL) indicating the degree of their center frequency.
Particularly, crystal oscillators intended for use in the R2043K/T are recommended to have a typical R1 value of
50kΩ and a typical CL value of 6 to 9pF. To confirm these recommended values, contact the manufacturers of
crystal oscillators intended for use in these particular models.
< Considerations in Installing Components around the Oscillation Circuit >
1) Install the crystal oscillator in the closest possible vicinity to the real-time clock ICs.
2) Avoid laying any signal lines or power lines in the vicinity of the oscillation circuit (particularly in the area
marked "A" in the above figure).
3) Apply the highest possible insulation resistance between the OSCIN and OSCOUT pins and the printed
circuit board.
4) Avoid using any long parallel lines to wire the OSCIN and OSCOUT pins.
5) Take extreme care not to cause condensation, which leads to various problems such as oscillation halt.
< Other Relevant Considerations >
1) For external input of 32.768-kHz clock pulses to the OSCIN pin:
DC coupling: Prohibited due to an input level mismatch.
AC coupling: Permissible except that the oscillation halt sensing circuit does not guarantee perfect
operation because it may cause sensing errors due to such factors as noise.
2) To maintain stable characteristics of the crystal oscillator, avoid driving any other IC through 32.768-kHz
clock pulses output from the OSCOUT pin.
Rev.2.05 - 27 -
12345
R2043K/T
A
A
Measurement of Oscillation Frequency
OSCOUT
32KOUT
VDD
OSCIN
VSS
32768Hz
Frequency
Counter
* 1) The R2043K/T is configured to generate 32.768-kHz clock pulses for output from the 32KOUT pin.
* 2) A frequency counter with 6 (more preferably 7) or more digits on the order of 1ppm is recommended
for use in the measurement of the oscillation frequency of the oscillation circuit.
Adjustment of Oscillation frequency
The oscillation frequency of the oscillation circuit can be adjusted by varying procedures depending on the usage
of Model R2043K/T in the system into which they are to be built and on the allowable degree of time count errors.
The flow chart below serves as a guide to selecting an optimum oscillation frequency adjustment procedure for
the relevant system.
Start
Use 32-kHz
clock output?
YES
Use 32-kHz clock output without regard
to its frequency precision
NO
llowable time count precision on order of oscillation
frequency variations of crystal oscillator (*1) plus
frequency variations of RTC (*2)? (*3)
llowable time count precision on order of oscillation
NO
frequency variations of crystal oscillator (*1) plus
frequency variations of RTC (*2)? (*3)
YES
YES
NO
YES
NO
Course (A)
Course (B)
Course (C)
Course (D)
* 1) Generally, crystal oscillators for commercial use are classified in terms of their center frequency
depending on their load capacitance (CL) and further divided into ranks on the order of ±10, ±20, and
±50ppm depending on the degree of their oscillation frequency variations.
* 2) Basically, Model R2043K/T is configured to cause frequency variations on the order of ±5 to ±10ppm
at 25°C.
* 3) Time count precision as referred to in the above flow chart is applicable to normal temperature and
actually affected by the temperature characteristics and other properties of crystal oscillators.
12345
Rev.2.06 - 28 -
R2043K/T
Course (A)
When the time count precision of each RTC is not to be adjusted, the crystal oscillator intended for use in that
RTC may have any CL value requiring no presetting. The crystal oscillator may be subject to frequency
variations which are selectable within the allowable range of time count precision. Several crystal oscillators
and RTCs should be used to find the center frequency of the crystal oscillators by the method described in "P.28
Adjustment of Oscillation frequency" and then calculate an appropriate oscillation adjustment value by the
method described in "P.31 Oscillation Adjustment Circuit" for writing this value to the R2043K/T.
Course (B)
When the time count precision of each RTC is to be adjusted within the oscillation frequency variations of the
crystal oscillator plus the frequency variations of the real-time clock ICs, it becomes necessary to correct
deviations in the time count of each RTC by the method described in " P.31 Oscillation Adjustment Circuit".
Such oscillation adjustment provides crystal oscillators with a wider range of allowable settings of their oscillation
frequency variations and their CL values. The real-time clock IC and the crystal oscillator intended for use in
that real-time clock IC should be used to find the center frequency of the crystal oscillator by the method
described in " P28 Measurement of Oscillation Frequency " and then confirm the center frequency thus
found to fall within the range adjustable by the oscillation adjustment circuit before adjusting the oscillation
frequency of the oscillation circuit. At normal temperature, the oscillation frequency of the oscillator circuit can
be adjusted by up to approximately ±0.5ppm.
Course (C)
Course (C) together with Course (D) requires adjusting the time count precision of each RTC as well as the
frequency of 32.768-kHz clock pulses output from the 32KOUT pin. Normally, the oscillation frequency of the
crystal oscillator intended for use in the RTCs should be adjusted by adjusting the oscillation stabilizing
capacitors CG and CD connected to both ends of the crystal oscillator. The R2043K/T, which incorporate the
CG and the CD, require adjusting the oscillation frequency of the crystal oscillator through its CL value.
Generally, the relationship between the CL value and the CG and CD values can be represented by the following
equation:
CL = (CG × CD)/(CG + CD) + CS where "CS" represents the floating capacity of the printed circuit board.
The crystal oscillator intended for use in the R2043K/T is recommended to have the CL value on the order of 6 to
9pF. Its oscillation frequency should be measured by the method described in " P.28 Measurement of
Oscillation Frequency ". Any crystal oscillator found to have an excessively high or low oscillation frequency
(causing a time count gain or loss, respectively) should be replaced with another one having a smaller and
greater CL value, respectively until another one having an optimum CL value is selected. In this case, the bit
settings disabling the oscillation adjustment circuit (see " P.31 Oscillation Adjustment Circuit") should be
written to the oscillation adjustment register.
Incidentally, the high oscillation frequency of the crystal oscillator can also be adjusted by adding an external
oscillation stabilization capacitor CGOUT or/and CDOUT as illustrated in the diagram below.
Oscillator
Circuit
CG
RD
CD
OSCIN
OSCOUT
32kHz
CGOUT
CDOUT
*1) The CGOUT or/and CDOUT should have a
capacitance ranging from 0 to 6 pF.
However, if adding CGOUT and/or CDOUT, Time keeping Voltage and Current will be worse, and it will be hard
to oscillate. For reference, the data of Time keeping voltage and current when adding CGOUT=CDOUT=5pF
are shown in the table below.
PIN Item Condition Min. TYP. MAX. UNITS
Vclk Time Keeping
Voltage
IDDTime Keeping
Current
CGout=CDout=5pF 1.15 5.5 V
VDD=3V, CE=OPEN, Output=OPEN
32KOUT=OFF
CGout=CDout=5pF
(Topt=-40 to 85°C, VSS=0v)
0.55 1.20
µA
12345
Rev.2.05 - 29 -
R2043K/T
Course (D)
It is necessary to select the crystal oscillator in the same manner as in Course (C) as well as correct errors
in the time count of each RTC in the same manner as in Course (B) by the method described in " P.31
Oscillation Adjustment Circuit ".
12345
Rev.2.06 - 30 -
R2043K/T
Oscillation Adjustment Circuit
The oscillation adjustment circuit can be used to correct a time count gain or loss with high precision by varying
the number of 1-second clock pulses once per 20 seconds or 60 seconds. When DEV bit in the Oscillation
Adjustment Register is set to 0, R2043K/T varies number of 1-second clock pulses once per 20 seconds. When
DEV bit is set to 1, R2043K/T varies number of 1-second clock pulses once per 60 seconds. The oscillation
adjustment circuit can be disabled by writing the settings of "*, 0, 0, 0, 0, 0, *" ("*" representing "0" or "1") to the
F6, F5, F4, F3, F2, F1, and F0 bits in the oscillation adjustment circuit. Conversely, when such oscillation
adjustment is to be made, an appropriate oscillation adjustment value can be calculated by the equation below
for writing to the oscillation adjustment circuit.
(1) When Oscillation Frequency (* 1) Is Higher Than Target Frequency (* 2) (Causing Time Count Gain)
When DEV=0:
Oscillation adjustment value (*3) = (Oscillation frequency - Target Frequency + 0.1)
Oscillation frequency × 3.051 × 10
-6
≈ (Oscillation Frequency – Target Frequency) × 10 + 1
When DEV=1:
Oscillation adjustment value (*3) = (Oscillation frequency - Target Frequency + 0.0333)
Oscillation frequency × 1.017 × 10
-6
≈ (Oscillation Frequency – Target Frequency) × 30 + 1
* 1) Oscillation frequency:
Frequency of clock pulse output from the 32KOUT pin at normal temperature in the manner described
in " P.28 Measurement of Oscillation Frequency ".
* 2) Target frequency:
Desired frequency to be set. Generally, a 32.768-kHz crystal oscillator has such temperature
characteristics as to have the highest oscillation frequency at normal temperature. Consequently,
the crystal oscillator is recommended to have target frequency settings on the order of 32.768 to
32.76810 kHz (+3.05ppm relative to 32.768 kHz). Note that the target frequency differs depending
on the environment or location where the equipment incorporating the RTC is expected to be
operated.
* 3) Oscillation adjustment value:
Value that is to be finally written to the F0 to F6 bits in the Oscillation Adjustment Register and is
represented in 7-bit coded decimal notation.
(2) When Oscillation Frequency Is Equal To Target Frequency (Causing Time Count neither Gain nor Loss)
Oscillation adjustment value = 0, +1, -64, or –63
(3) When Oscillation Frequency Is Lower Than Target Frequency (Causing Time Count Loss)
When DEV=0:
Oscillation adjustment value = (Oscillation frequency - Target Frequency)
Oscillation frequency × 3.051 × 10
-6
≈ (Oscillation Frequency – Target Frequency) × 10
When DEV=1:
Oscillation adjustment value = (Oscillation frequency - Target Frequency)
Oscillation frequency × 1.017 × 10
-6
≈ (Oscillation Frequency – Target Frequency) × 30
Oscillation adjustment value calculations are exemplified below
(A) For an oscillation frequency = 32768.85Hz and a target frequency = 32768.05Hz
When setting DEV bit to 0:
Oscillation adjustment value = (32768.85 - 32768.05 + 0.1) / (32768.85 × 3.051 × 10
≈ (32768.85 - 32768.05) × 10 + 1
= 9.001 ≈ 9
In this instance, write the settings (DEV,F6,F5,F4,F3,F2,F1,F0)=(0,0,0,0,1,0,0,1) in the oscillation adjustment
register. Thus, an appropriate oscillation adjustment value in the presence of any time count gain represents a
distance from 01h.
When setting DEV bit to 1:
-6
)
Rev.2.05 - 31 -
12345
R2043K/T
Oscillation adjustment value = (32768.85 - 32768.05 + 0.0333) / (32768.85 × 1.017 × 10-6)
≈ (32768.85 - 32768.05) × 30 + 1
= 23.51 ≈ 24
In this instance, write the settings (DEV,F6,F5,F4,F3,F2,F1,F0)=(1,0,0,1,1,0,0,0) in the oscillation adjustment
register.
(B) For an oscillation frequency = 32762.22Hz and a target frequency = 32768.05Hz
When setting DEV bit to 0:
Oscillation adjustment value = (32762.22 - 32768.05) / (32762.22 × 3.051 × 10
≈ (32762.22 - 32768.05) × 10
= -58.325 ≈ -58
To represent an oscillation adjustment value of - 58 in 7-bit coded decimal notation, subtract 58 (3Ah) from 128
(80h) to obtain 46h. In this instance, write the settings of (DEV,F6,F5,F4,F3,F2,F1,F0) = (0,1,0,0,0,1,1,0) in the
oscillation adjustment register. Thus, an appropriate oscillation adjustment value in the presence of any time
count loss represents a distance from 80h.
When setting DEV bit to 1:
Oscillation adjustment value = (32762.22 - 32768.05) / (32762.22 × 1.017 × 10
≈ (32762.22 - 32768.05) × 30
= -174.97 ≈ -175
Oscillation adjustment value can be set from -62 to 63. Then, in this case, Oscillation adjustment value is out of
range.
(4) Difference between DEV=0 and DEV=1
Difference between DEV=0 and DEV=1 is following,
DEV=0 DEV=1
Maximum value range -189.2ppm to 189.2ppm --62ppm to 63ppm
Minimum resolution 3ppm 1ppm
Notes:
1) Oscillation adjustment does not affect the frequency of 32.768-kHz clock pulses output from the
32KOUT pin.
2) If following 3 conditions are completed, actual clock adjustment value could be different from target
adjustment value that set by oscillator adjustment function.
1. Using oscillator adjustment function
2. Access to R2043K/T at random, or synchronized with external clock that has no relation to R2043K/T,
or synchronized with periodic interrupt in pulse mode.
3. Access to R2043K/T more than 2 times per each second on average.
For more details, please contact to Ricoh.
How to evaluate the clock gain or loss
The oscillator adjustment circuit is configured to change time counts of 1 second on the basis of the settings of
the oscillation adjustment register once in 20 seconds or 60 seconds. The oscillation adjustment circuit does
not effect the frequency of 32768Hz-clock pulse output from the 32KOUT pin. Therefore, after writing the
oscillation adjustment register, we cannot measure the clock error with probing 32KOUT clock pulses. The way
to measure the clock error as follows:
(1) Output a 1Hz clock pulse of Pulse Mode with interrupt pin
Set (0,0,x,x,0,0,1,1) to Control Register 1 at address Eh.
(2) After setting the oscillation adjustment register, 1Hz clock period changes every 20seconds ( or every 60
seconds) like next page figure.
-6
)
-6
)
12345
Rev.2.06 - 32 -
1Hz clock pulse
R2043K/T
T0 T0 T0T1
1 time 19 times
Measure the interval of T0 and T1 with frequency counter. A frequency counter with 7 or more digits is
recommended for the measurement.
(3) Calculate the typical period from T0 and T1
T = (19×T0+1×T1)/20
Calculate the time error from T.
Rev.2.05 - 33 -
12345
R2043K/T
g
)
Power-on Reset, Oscillation Halt Sensing, and Supply Voltage Monitoring
PON, /XST, and VDET
The power-on reset circuit is configured to reset control register1, 2, and clock adjustment register when VDD
power up from 0v. The oscillation halt sensing circuit is configured to record a halt on oscillation by 32.768-kHz
clock pulses. The supply voltage monitoring circuit is configured to record a drop in supply voltage below a
threshold voltage of 1.6 or 1.3v.
Each function has a monitor bit. I.e. the PON bit is for the power-on reset circuit, and /XST bit is for the
oscillation halt sensing circuit, and VDET is for the supply voltage monitoring circuit. PON and VDET bits are
activated to “H”. However, /XST bit is activated to “L”. The PON and VDET accept only the writing of 0, but
/XST accepts the writing of 0 and 1. The PON bit is set to 1, when VDD power-up from 0V, but VDET is set to 0,
and /XST is indefinite.
The functions of these three monitor bits are shown in the table below.
PON /XST VDET
Function Monitoring for the
power-on reset function
Address D4 in Address Fh D5 in Address Fh D6 in Address Fh
Activated High Low High
When VDD power
1 indefinite 0
up from 0v
accept the writing 0 only Both 0 and 1 0 only
The relationship between the PON, /XST, and VDET is shown in the table below.
PON /XST VDET Conditions of supply voltage and
oscillation
0 0 0 Halt on oscillation, but no drop in
VDD supply voltage below threshold
voltage
0 0 1 Halt on oscillation and drop in VDD
supply voltage below threshold
voltage, but no drop to 0V
0 1 0 No drop in VDD supply voltage below
threshold voltage and no halt in
oscillation
0 1 1 Drop in VDD supply voltage below
threshold voltage and no halt on
oscillation
1 * * Drop in supply voltage to 0v Power-up from 0v,
Monitoring for the
oscillation halt sensing
function
Condition of oscillator, and back-up
status
Halt on oscillation cause of
condensation etc.
Halt on oscillation cause of drop in
back-up battery voltage
Normal condition
No halt on oscillation, but drop in
back-up battery voltage
Threshold voltage (1.6v or 1.3v)
a drop in supply voltage
below a threshold voltage
of 1.6 or 1.3v
VDD
32768Hz Oscillation
Power-on reset flag
(PON)
Oscillation halt
sensin
monitor flag (VDET)
flag (/XST
Supply voltage
Internal initialization
period (1 to 2 sec.)
VDET←0
/XST←1
PON←0
VDET←0
/XST←1
PON←1
Internal initialization
period (1 to 2 sec.)
VDET←0
/XST←1
PON←0
When the PON bit is set to 1 in the control register 2, the DEV, F6 to F0, WALE, DALE, /12⋅24, /CLEN2, TEST,
12345
Rev.2.06 - 34 -
R2043K/T
CT2, CT1, CT0, VDSL, VDET, /CLEN1, CTFG, WAFG, and DAFG bits are reset to 0 in the oscillation adjustment
register, the control register 1, and the control register 2. The PON bit is also set to 1 at power-on from 0v.
< Considerations in Using Oscillation Halt Sensing Circuit >
Be sure to prevent the oscillation halt sensing circuit from malfunctioning by preventing the following:
1) Instantaneous power-down on the VDD
2) Condensation on the crystal oscillator
3) On-board noise to the crystal oscillator
4) Applying to individual pins volt age exceeding their respective maximum ratings
In particular, note that the /XST bit may fail to be set to 0 in the presence of any applied supply voltage as
illustrated below in such events as backup battery installation. Further, give special considerations to prevent
excessive chattering in the oscillation halt sensing circuit.
VDD
Rev.2.05 - 35 -
12345
R2043K/T
(
)
(
)
Voltage Monitoring Circuit
The supply monitoring circuit is configured to conduct a sampling operation during an interval of 7.8ms per
second to check for a drop in supply voltage below a threshold voltage of 1.6 or 1.3v for the VDSL bit setting of 0
(the default setting) or 1, respectively, in the Control Register 2, thus minimizing supply current requirements as
illustrated in the timing chart below. This circuit suspends a sampling operation once the VDET bit is set to 1 in
the Control Register 2. The supply voltage monitor is useful for back-up battery checking.
Sampling timing for
VDD supply voltage
D6 in Address Fh
VDD
PON
VDET
Internal
initialization
period
1 to 2sec.
PON←0
VDET
←0
1.6v or 1.3v
7.8ms
1s
VDET←0
12345
Rev.2.06 - 36 -
R2043K/T
Alarm and Periodic Interrupt
The R2043K/T incorporates the alarm interrupt circuit and the periodic interrupt circuit that are configured to
generate alarm signals and periodic interrupt signals for output from the /INTR pin as described below.
(1) Alarm Interrupt Circuit
The alarm interrupt circuit is configured to generate alarm signals for output from the /INTR, which is driven low
(enabled) upon the occurrence of a match between current time read by the time counters (the day-of-week,
hour, and minute counters) and alarm time preset by the alarm registers (the Alarm_W registers intended for the
day-of-week, hour, and minute digit settings and the Alarm_D registers intended for the hour and minute digit
settings).
(2) Periodic Interrupt Circuit
The periodic interrupt circuit is configured to generate either clock pulses in the pulse mode or interrupt signals in
the level mode for output from the /INTR pin depending on the CT2, CT1, and CT0 bit settings in the control
register 1.
The above two types of interrupt signals are monitored by the flag bits (i.e. the WAFG, DAFG, and CTFG bits in
the Control Register 2) and enabled or disabled by the enable bits (i.e. the WALE, DALE, CT2, CT1, and CT0
bits in the Control Register 1) as listed in the table below.
Flag bits Enable bits
Alarm_W WAFG
(D1 at Address Fh)
Alarm_D DAFG
(D0 at Address Fh)
Peridic interrupt CTFG
(D2 at Address Fh)
* At power-on, when the WALE, DALE, CT2, CT1, and CT0 bits are set to 0 in the Control Register 1,
the /INTR pin is driven high (disabled).
* When two types of interrupt signals are output simultaneously from the /INTR pin, the output from the
/INTR pin becomes an OR waveform of their negative logic.
Example: Combined Output to /INTR Pin Under Control of
/ALARM_D and Periodic Interrupt
WALE
(D7 at Address Eh)
DALE
(D6 at Address Eh)
CT2=CT1=CT0=0
(These bit setting of “0” disable the Periodic Interrupt)
(D2 to D0 at Address Eh)
/Alarm_D
Periodic Interrupt
In this event, which type of interrupt signal is output from the /INTR pin can be confirmed by reading the
DAFG, and CTFG bit settings in the Control Register 2.
Alarm Interrupt
The alarm interrupt circuit is controlled by the enable bits (i.e. the WALE and DALE bits in the Control Register 1)
and the flag bits (i.e. the WAFG and DAFG bits in the Control Register 2). The enable bits can be used to
enable this circuit when set to 1 and to disable it when set to 0. When intended for reading, the flag bits can be
used to monitor alarm interrupt signals. When intended for writing, the flag bits will cause no event when set to
1 and will drive high (disable) the alarm interrupt circuit when set to 0.
The enable bits will not be affected even when the flag bits are set to 0. In this event, therefore, the alarm
interrupt circuit will continue to function until it is driven low (enabled) upon the next occurrence of a match
between current time and preset alarm time.
/INTR
12345
Rev.2.05 - 37 -
R2043K/T
←
A
The alarm function can be set by presetting desired alarm time in the alarm registers (the Alarm_W Registers for
the day-of-week digit settings and both the Alarm_W Registers and the Alarm_D Registers for the hour and
minute digit settings) with the WALE and DALE bits once set to 0 and then to 1 in the Control Register 1. Note
that the WALE and DALE bits should be once set to 0 in order to disable the alarm interrupts circuit upon the
coincidental occurrence of a match between current time and preset alarm time in the process of setting the
alarm function.
Interval (1min.) during which a match
between current time and preset alarm time
occurs
/INTR
/INTR
WALE←1
(DALE)
WALE←1
(DALE)
current time =
preset alarm time
current time =
preset alarm time
WALE
(DALE)
WALE←1
0
(DALE)
WAFG←0
(DAFG)
current time =
preset alarm time
current time =
preset alarm time
After setting WALE(DALW) to 0, Alarm registers is set to current time, and WALE(DALE) is set to 1, /INTR will be
not driven to “L” immediately, /INTR will be driven to “L” at next alarm setting time.
Periodic Interrupt
Setting of the periodic selection bits (CT2 to CT0) enables periodic interrupt to the CPU. There are two waveform
modes: pulse mode and level mode. In the pulse mode, the output has a waveform duty cycle of around 50%.
In the level mode, the output is cyclically driven low and, when the CTFG bit is set to 0, the output is return to
High (OFF).
CT2 CT1 CT0
Description
Wave form mode Interrupt Cycle and Falling Timing
0 0 0 - OFF(H) (Default)
0 0 1 - Fixed at “L”
0 1 0 Pulse Mode *1) 2Hz(Duty50%)
0 1 1 Pulse Mode *1) 1Hz(Duty50%)
1 0 0 Level Mode *2) Once per 1 second (Synchronized with
Second counter increment)
1 0 1 Level Mode *2) Once per 1 minute (at 00 seconds of every
Minute)
1 1 0 Level Mode *2) Once per hour (at 00 minutes and 00
Seconds of every hour)
1 1 1 Level Mode *2) Once per month (at 00 hours, 00 minutes,
and 00 seconds of first day of every month)
*1) Pulse Mode:
2-Hz and 1-Hz clock pulses are output in synchronization with the increment of the second counter as
illustrated in the timing chart below.
12345
CTFG Bit
/INTR Pin
pprox. 92µs
(Increment of second counter)
Rewriting of the second counter
Rev.2.06 - 38 -
In the pulse mode, the increment of the second counter is delayed by approximately 92 µs from the
falling edge of clock pulses. Consequently, time readings immediately after the falling edge of clock
pulses may appear to lag behind the time counts of the real-time clocks by approximately 1 second.
Rewriting the second counter will reset the other time counters of less than 1 second, driving the
/INTR pin low.
*2) Level Mode:
Periodic interrupt signals are output with selectable interrupt cycle settings of 1 second, 1 minute, 1
hour, and 1 month. The increment of the second counter is synchronized with the falling edge of
periodic interrupt signals. For example, periodic interrupt signals with an interrupt cycle setting of 1
second are output in synchronization with the increment of the second counter as illustrated in the
timing chart below.
CTFG Bit
R2043K/T
/INTR Pin
Setting CTFG bit to 0
(Increment of
second counter)
(Increment of
second counter)
(Increment of
second counter)
Setting CTFG bit to 0
*1), *2) When the oscillation adjustment circuit is used, the interrupt cycle will fluctuate once per 20sec. as
follows:
Pulse Mode: The “L” period of output pulses will increment or decrement by a maximum of
example, 1-Hz clock pulses will have a duty cycle of 50
±0.3784%.
±3.784ms. For
Level Mode: A periodic interrupt cycle of 1 second will increment or decrement by a maximum of
32-kHz CLOCK OUTPUT
For the R2043K/T, 32.768-kHz clock pulses are output from the 32KOUT pin when either the /CLEN1 bit in
the Control Register 2 or the /CLEN2 bit in the Control Register 1 is set to 0. When both the /CLEN1 and
/CLEN2 bits are set to 0, the 32KOUT pin output is driven high (off).
/CLEN1
(D3 at Address Fh)
/CLEN2
(D4 at Address Eh)
32KOUT PIN
(N-channel Open Drain)
1 1 OFF(H)
0(Default) *
Clock pulses
* 0(Default)
The 32KOUT pin output is synchronized with the /CLEN1 and /CLEN2 bit settings as illustrated in the timing
chart below.
±3.784 ms.
/CLEN1or2
32KOUT PIN
Max.62.0µs
Rev.2.05 - 39 -
12345
R2043K/T
r
Typical Applications
Typical Power Circuit Configurations
Sample circuit configuration 1
System power supply
OSCIN
*1) Install bypass capacitors for high-frequency
and low-frequency applications in parallel in
close vicinity to the R2043K/T.
OSCOUT
32768Hz
VDD
*1)
VSS
Sample circuit configuration 2
OSCIN
OSCOUT
VDD
32768Hz
System power supply
*1)
*1) When using an OR diode as a power supply fo
the R2043K/T ensure that voltage exceeding
the absolute maximum rating of VDD+0.3v is
not applied the 32KOUT pin.
Primary
VSS
Battery
OSCIN
OSCOUT
VDD
VSS
32768Hz
System power supply
*1)
Secondary
Battery
12345
Rev.2.06 - 40 -
R2043K/T
A
T
Connection of /INTR and 32KOUT Pin
The /INTR pin follows the N-channel open drain output logic and contains no protective diode on the power
supply side. As such, it can be connected to a pull-up resistor of up to 5.5v regardless of supply voltage.
The 32KOUT pin follows the N-channel open drain output logic, too. However, it contains protective diode on the
power supply side. As such, it cannot be connected to a pull-up resistor over VDD+0.3v. Such connection
involves considerations for the supply current requirements of a pull-up resistor, which can be roughly calculated
by the following equation:
I = 0.5
/INTR or 32KOUT
OSCIN
OSCOUT
VSB
× (VDD or VCC) / Rp
32768Hz
System power supply
(VDD)
*1)
B
Backup power supply
(VCC)
*1) Depending on whether the /INTR or 32KOU
pins are to be used during battery backup, it
should be connected to a pull-up resistor at
the following different positions:
(1) Position A in the left diagram when it is not to
be used during battery backup.
(2) Position B in the left diagram when it is to be
used during battery backup.
VSS
Connection of CE Pin
Connection of the CE pin requires the following considerations:
1) The CE pin is configured to enable the oscillation halt sensing circuit only when driven low. As such, it
should be driven low or open at power-on from 0v.
2) The CE pin should also be driven low or open immediately upon the host going down (see "P.25
Considerations in Reading and Writing Time Data under special condition").
I/O
CONTROL
SCLK
SI
SO
CE
VDD
CE
Lower limit operating
voltage for the CPU
Backup power supply
0.2×VDD
Min.0µsMin.0µs
Min.0µs
12345
Rev.2.05 - 41 -
R2043K/T
K
A
K
K
Connection With 3-Wire Serial Interface Bus
To connect the R2043K/T with 3-wire serial interface bus, shorten the SI and SO pins and connect them to the
data line as shown in the figure below .
CE0
CE
Host
CE1
SCL
DAT
SCL
SI
SO
CE
SCL
SIO
R2043
The other
Peripheral IC
12345
Rev.2.06 - 42 -
Typical Characteristics
Test circuit
R2043K/T
OSCOUT
VDD
OSCIN
32KOUT
VSS
CGOUT
32768Hz
CDOUT
Frequency
Counter
X’tal : 32.768kHz
(R1=50k
Ω typ)
(CL=6pF to 9pF)
Topt : 25
°C
Output pins : Open
Timekeeping Current vs. Supply Voltage Timekeeping Current vs. Supply Voltage
(with no 32kHz clock output) (with 32kHz clock output)
(CE=Open, Output=Open, Topt=25
1
0.8
0.6
0.4
0.2
0
Timekeeping Current IDD(uA)
(CGout, CDout)=(5pF, 5pF)
(CGout, CDout)=(0pF, 0pF)
0123456
Supply Vlotage VDD(v)
°C) (CE=Open, Output=Open, Topt=25°C)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Timekeeping Current IDD(uA)
0123456
(CGout, CDout)=(5pF, 5pF)
(CGout, CDout)=(0pF, 0pF)
Supply Voltage VDD(v)
CPU Access Current vs. SCLK Clock Frequency Timekeeping Current vs. Operating Temperature
(Output pins=Open, Topt=25
°C, CGout=CDout=0pF) (CE=Open, Output pins=Open, CGout=CDout=0pF)
80
70
60
50
40
30
20
10
0
CPU Access Current IDD(uA)
02004006008001000
SCLK Clock Frequency (kHz)
VDD=5v
VDD=3v
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Timekeeping Current IDD(uA)
Rev.2.05 - 43 -
with 32kHz clock output
with no 32kHz clock output
-50-250255075100
Operating Temperature Topt(Celcius)
12345
R2043K/T
Oscillation Frequency Deviation vs. External CF, CD Oscillation Frequency Deviation vs. Supply Voltage
(VDD=3v , Topt=25
°C, CGout=CDout=0pF as standard) (Topt=25°C,VDD=3v as standard)
0
-10
-20
-30
-40
-50
(ppm)
-60
-70
-80
-90
-100
Oscillation Frequency Deviation
05101520
External CG (pF)
CDout=0pF
CDout=5pF
5
4
3
2
1
0
(ppm)
-1
-2
-3
-4
-5
Oscillation Frequency Deviation
0123456
Supply Voltage VDD (v)
Oscillation Frequency Deviation vs. VOL vs. IOL (32KOUT)
Operating Temperature (Topt=25
(VDD=3v , Topt=25
20
-20
-40
-60
(ppm)
-80
-100
-120
Oscillation Frequency Deviation
°C as standard)
0
-60 -40 -20 0 20 40 60 80 10
Operating TemperatureTopt(Celsius)
7
6
5
4
3
IOL (mA)
2
1
0
0
00.10.20.30.40.5
°C)
VDD=5v
VDD=3v
VDD=1.5v
VOL (v)
VOL vs. IOL (/INTR pin)
(Topt=25
°C)
30
25
20
15
IOL(mA)
10
5
0
00.10.20.30.40.5
VOL(v)
VDD=5v
VDD=3v
VDD=1.5v
12345
Rev.2.06 - 44 -
y
A
Typical Software-based Operations
Initialization at Power-on
R2043K/T
Start
*1)
Power-on
*2)
PON=1?
Yes
*4)
Set Oscillation Adjustment
Register and Control
Register 1 and 2, etc.
No
VDET=0?
Yes
*3)
No
Warnin g B a ck -u p
Batter
Run-down
*1) After power-on from 0 volt, the start of oscillation and the process of internal initialization require a
time span on 1to 2seconds, so that access should be done after the lapse of this time span or more.
*2) The PON bit setting of 0 in the Control Register 1 indicates power-on from backup battery and not
from 0v. For further details, see "P.34
PON, /XST, and VDET".
*3) This step is not required when the supply voltage monitoring circuit is not used.
*4) This step involves ordinary initialization including the Oscillation Adjustment Register and interrupt
cycle settings, etc.
Writing of T ime and Calendar Data
CE ← H
Write to Time Counter and
Calendar Counter
CE ← L
*1)
*1) When writing to clock and calendar counters, do not drive CE to “L” until
*2)
*3)
all times from second to year have been written to prevent error in writing
time. (Detailed in "P.24
Time Data under special condition
*2) Any writing to the second counter will reset divider units lower than the
second digits.
*3) Take care so that process from CE driving to “H” to driving to “L” will be
complete within 1.0sec. (Detailed in "P.24
frequency
The R2043K/T may also be initialized not at power-on but in the process
of writing time and calendar data.
".
Considerations in Reading and Writing
".
djustment of Oscillation
12345
Rev.2.05 - 45 -
R2043K/T
r
Reading Time and Calendar Dat a
(1) Ordinary Process of Reading Time and Calendar Dat a
CE ← H
Read from Time Counter
and Calendar Counter
CE ← L
*1)
*2)
*1) When writing to clock and calendar counters, do not insert Stop Condition
until all times from second to year have been written to prevent error in
writing time. (Detailed "P.24
Time Data under special condition
*2) Take care so that process from Start Condition to Stop Condition will be
complete within 0.5sec. (Detailed in "P.24
Reading and Writing Time Data under special condition
Considerations in Reading and Writing
".
Considerations in
".
(2) Basic Process of Reading Time and Calendar Dat a with Periodic Interrupt Function
Set Periodic Interrupt
Cycle Selection Bits
Generate Interrupt in CPU
CTFG=1?
Yes
Read from Time Counter
and Calendar Counte
*2)
*1)
No
Other Interrupt
Processes
*1) This step is intended to select the level mode as a
waveform mode for the periodic interrupt function.
*2) This step must be completed within 1.0 second.
*3) This step is intended to set the CTFG bit to 0 in the
Control Register 2 to cancel an interrupt to the CPU.
*3)
Control Register 2
←(X1X1X011)
12345
Rev.2.06 - 46 -
R2043K/T
r
(3) Applied Process of Reading Time and Calendar Data with Periodic Interrupt Function
Time data need not be read from all the time counters when used for such ordinary purposes as time count
indication. This applied process can be used to read time and calendar data with substantial reductions in the
load involved in such reading.
For Time Indication in "Day-of-Month, Day-of-week, Hour, Minute, and Second" Format:
Control Register 1←
(XXXX0100)
Control Register 2←
(X1X1X011)
Generate interrupt to CPU
CTFG=1?
Yes
*2)
Sec.=00?
*1)
No
No
Other interrupts
Processes
*1) This step is intended to select the level
mode as a waveform mode for the
periodic interrupt function.
*2) This step must be completed within 1.0
sec.
*3) This step is intended to read time data
from all the time counters only in the
first session of reading time data afte
writing time data.
*4) This step is intended to set the CTFG
bit to 0 in the Control Register 2 to
cancel an interrupt to the CPU.
Read Min.,Hr.,Day,
and Day-of-week
Control Register 2←
(X1X1X011)
Yes
*3)
Use previous Min.,Hr.,
Day, and Day-of-week data
*4)
Rev.2.05 - 47 -
12345
R2043K/T
p
Interrupt Process
(1) Periodic Interrupt
Set Periodic Interrupt
Cycle Selection Bits
Generate Interrupt to CPU
*1)
*1) This step is intended to select the level mode as a
waveform mode for the periodic interrupt function.
*2) This step is intended to set the CTFG bit to 0 in
the Control Register 2 to cancel an interrupt to the
CPU.
CTFG=1?
Yes
Conduct
Periodic Interru
Control Register 2←
(X1X1X011)
(2) Alarm Interrupt
WALE or DALE←0
Set Alarm Min., Hr., and
Day-of-week Registers
WALE or DALE←1
t
*2)
No
*1)
*2)
Other Interrupt
Processes
*1) This step is intended to once disable the alarm
interrupt circuit by setting the WALE or DALE bits to 0
in anticipation of the coincidental occurrence of a
match between current time and preset alarm time in
the process of setting the alarm interrupt function.
*2) This step is intended to enable the alarm interrupt
function after completion of all alarm interrupt
settings.
*3) This step is intended to once cancel the alarm
interrupt function by writing the settings of "X,1,X,
1,X,1,0,1" and "X,1,X,1,X,1,1,0" to the Alarm_W
Registers and the Alarm_D Registers, respectively.
Generate Interrupt to CPU
No
WAFG or DAFG=1?
Yes
Conduct Alarm Interrupt
Other Interrupt
Processes
*3)
Control Register 2 ←
(X1X1X101)
12345
Rev.2.06 - 48 -
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