EM EM3027IDSSO08A Real time clock with i2c or spi, crystal temperature compensation, battery switchover and trickle charger Datasheet

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EM MICROELECTRONIC - MARIN SA
EM3027
Real Time Clock with I2C or SPI, Crystal Temperature
Compensation, Battery Switchover and Trickle Charger
Description
The EM3027 is an Ultra Low Power CMOS real-time
clock IC with two serial interface modes: I2C or SPI. The
interface mode is selected by the chip version (see §12).
The basic clock is obtained from the 32.768 kHz crystal
oscillator. A thermal compensation of the frequency is
based on the temperature measurement and calculation
of the correction value. The temperature can be
measured internally or be input by an external application
to the register.
The chip provides clock and calendar information in BCD
format with alarm possibility. The actual contents are
latched at the beginning of a read transmission and
afterwards data are read without clock counter data
corruption.
An integrated 16-bit timer can run in Zero-Stop or AutoReload mode.
An interrupt request signal can be provided through
INT/IRQ pin generated from alarm, timer, voltage
detector and Self-Recovery system.
An integrated trickle charger allows recharging backup
supply VBack from the main supply voltage VCC through
internal resistor(s). The internal device supply will
switchover to VCC when VCC is higher than VBack and vice
versa.
The device operates over a wide 1.4 to 5.5V supply
range and requires only 900 nA at 5V. It can detect
internally two supply voltage levels.
Applications
‰ Utility meters
‰ Battery operated and portable equipment
‰ Consumer electronics
‰ White/brown goods
‰ Pay phones
‰ Cash registers
‰ Personal computers
‰ Programmable controller systems
‰ Data loggers
Features
‰ Fully operational from 2.1 to 5.5V
‰ Supply current typically 600 nA at 1.4V
‰ Thermal compensated crystal frequency
‰ Oscillator stability 0.5 ppm / Volt
‰ Counter for seconds, minutes, hours, day of week,
date months, years in BCD format and alarm
‰ Leap year compensation
‰ 16-bits timer with 2 working modes
‰ Two low voltage detection levels VLow1, VLow2
‰ Automatic supply switchover
2
‰ Serial communication via I2C (I C-bus specification
Rev. 03 compatible – see §10.2) or SPI (3-line SPIbus with separate combinable data input and output)
‰ Thermometer readable by the host
‰ Trickle charger to maintain battery charge
‰ Integrated oscillator capacitors
‰ Two EEPROM and 8 RAM data bytes for application
‰ Digital Self-Recovery system
‰ No busy states and no risk of corrupted data while
accessing
‰ One hour periodical configuration registers refresh
‰ Support for standard UL1642 for Lithium batteries
‰ Standard temperature range: -40°C to +85°C
‰ Extended temperature range: -40°C to +125°C
‰ Packages: TSSOP8, TSSOP14, SO8.
Block Diagram
EM3027
Temperature
Sensor
X1
Oscillator
X2
VCC
VREG
VBack
SCL/SCK
SDA/SO
SI
Power
Management
I2C
or SPI
CS
CLKOUT
INT or IRQ
CLKOE
Watch & Alarm
- Seconds
- Minutes
- Hours
- Days
- Weekdays
- Months
- Years
Timer
Output
Control
EEPROM
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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EM3027
Table of contents
Table of contents..................................................................................................................................................................... 2
1 Packages / Pin Out Configuration .................................................................................................................................... 3
2 Absolute Maximum Ratings.............................................................................................................................................. 4
2.1 Handling Procedures................................................................................................................................................. 4
2.2 Operating Conditions ................................................................................................................................................ 4
2.3 Crystal characteristics ............................................................................................................................................... 4
2.4 EEPROM Characteristics .......................................................................................................................................... 4
3 Electrical Characteristics .................................................................................................................................................. 4
4 EM3027 Block Diagram and Application Schematic......................................................................................................... 6
4.1 Block Diagram........................................................................................................................................................... 6
4.2 Application Schematic ............................................................................................................................................... 6
4.3 Crystal Thermal Behaviour........................................................................................................................................ 7
4.4 Crystal Calibration..................................................................................................................................................... 8
5 Memory Mapping.............................................................................................................................................................. 9
6 Definitions of terms in the memory mapping .................................................................................................................. 10
7 Serial communication ..................................................................................................................................................... 12
7.1 How to perform data transmission through I2C ....................................................................................................... 12
7.2 How to perform data transmission through SPI....................................................................................................... 13
8 Functional Description.................................................................................................................................................... 15
8.1 Start after power-up ................................................................................................................................................ 15
8.2 Normal Mode function ............................................................................................................................................. 15
8.3 Watch and Alarm function ....................................................................................................................................... 15
8.4 Timer function ......................................................................................................................................................... 16
8.5 Temperature measurement..................................................................................................................................... 16
8.6 Frequency compensation ........................................................................................................................................ 16
8.7 EEPROM memory................................................................................................................................................... 17
8.8 RAM User Memory.................................................................................................................................................. 18
8.9 Status Register........................................................................................................................................................ 18
8.10
Interrupts ............................................................................................................................................................ 18
8.11
Self-Recovery System (SRS) ............................................................................................................................. 19
8.12
Register Map ...................................................................................................................................................... 19
8.13
Crystal Oscillator and Prescaler ......................................................................................................................... 19
9
Power Management ................................................................................................................................................ 20
9.1 Power Supplies, Switchover and Trickle Charger ................................................................................................... 20
9.2 Low Supply Detection ............................................................................................................................................. 21
10
AC Characteristics .................................................................................................................................................. 22
10.1
AC characteristics – I2C ..................................................................................................................................... 22
10.2
I2C Specification compliance ............................................................................................................................. 23
10.3
AC characteristics – SPI..................................................................................................................................... 24
11
Package Information ............................................................................................................................................... 26
11.1
TSSOP-08/14 ..................................................................................................................................................... 26
11.2
SO-8................................................................................................................................................................... 27
12
Ordering Information ............................................................................................................................................... 28
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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EM3027
1
Packages / Pin Out Configuration
SO8-TSSOP8
Vcc
X1
X2
VBack
IRQ/CLKOUT
EM3027
SCL
Vss
SDA
I2C
TSSOP14
X1
NC
X2
CLKOE
SI
VCC
VReg
EM3027
VBack
IRQ/CLKOUT
CS
INT
SCK
Vss
SO
SPI
Pin
1
2
3
4
5
6
7
8
Table 1
Name
X1
X2
VBack
VSS
SDA
SCL
IRQ/CLKOUT
VCC
Pin
1
2
3
Name
X1
X2
SI
4
VReg
5
VBack
INT
6
7
8
9
10
11
12
VSS
SO
SCK
CS
IRQ/CLKOUT
VCC
13
CLKOE
14
NC
Table 2
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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Function
32.768 kHz crystal input
32.768 kHz crystal output
Backup Supply
Ground Supply
Serial Data
Serial Clock
Interrupt Request/Clock output
Positive Supply
Function
32.768 kHz crystal input
32.768 kHz crystal output
Serial Data input
Regulated Voltage – Reserved for
test purpose (This output must be
left unconnected)
Backup Supply
Interrupt Request output
(Open Drain active low)
Ground Supply
Serial Data output
Serial Clock input
Chip Select input
Interrupt Request/Clock output
Positive Supply
Clock Output Enable
CLKOE = ‘0’ CLKOUT is low
CLKOE = ‘1’ CLKOUT is output
Not Connected
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EM3027
2
Operating Conditions
Absolute Maximum Ratings
Parameter
Maximum voltage at VCC
Minimum voltage at VCC
Maximum voltage at any
signal pin
Minimum voltage at any signal
pin
Maximum storage
temperature
Minimum storage temperature
Electrostatic discharge
maximum to MIL-STD-883C
method 3015.7 with ref. to VSS
Table 3
Symbol
VCCmax
VCCmin
Conditions
VSS + 6.0V
VSS – 0.3V
Vmax
VCC + 0.3V
Vmin
VSS – 0.3V
TSTOmax
+150°C
TSTOmin
-65°C
VSmax
2000V
Parameter
Symbol
2.3
Symbol
Frequency
Load capacitance
Series resistance
Table 5
Max
Unit
+125
°C
5.5
V
nF
Min
f
CL
RS
7
Typ
Max
Unit
32.768
kHz
8.2
12.5 pF
70
110 kΩ
Crystal Reference : Micro Crystal CC5V-T1A
web: www.microcrystal.com
2.4
EEPROM Characteristics
Parameter
Handling Procedures
Symbol
Read voltage
Programming
Voltage
This device has built-in protection against high static
voltages or electric fields; however, anti-static
precautions must be taken as for any other CMOS
component. Unless otherwise specified, proper operation
can only occur when all terminal voltages are kept within
the voltage range. Unused inputs must always be tied to
a defined logic voltage level.
EEPROM
Programming Time
Write/Erase
Cycling
Table 6
2.2
3
Typ
Crystal characteristics
Parameter
Stresses above these listed maximum ratings may cause
permanent damages to the device.
Exposure beyond specified operating conditions may
affect device reliability or cause malfunction.
2.1
Min
TA
Operating Temp.
-40
Supply voltage
VCC,
1.4
5.0
VBack
(Note 1)
Capacitor at VCC,
CD
100
VBack
Table 4
Note 1: Refer to paragraphs 9.1 and 9.2
Min
Typ
Max
Unit
VRead
1.4
V
VProg
2.2
V
30
TProg
5000
ms
cycles
Electrical Characteristics
Parameter
Total supply current with
Crystal
Total supply current with
Crystal
Symbol
ICC
IBack
Test Conditions
All outputs open, Rs < 70
kΩ, VBack = 0V
I2C: SDA, SCL at VCC,
Clk/Int=’0’
SPI: All inputs at VSS
VCC
1.4
3.3
5.0
All outputs open, Rs < 70
kΩ, VCC = 0V
I2C: SDA, SCL at VBack,
Clk/Int=’0’
SPI: All inputs at VSS
VBack
1.4
3.3
0
5.0
Dynamic current
I2C
IDD
SCL = 100kHz
(See Note 1)
SCL = 400kHz
(See Note 1)
SCL = 400kHz
(See note 1)
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
1.4
3.3
5.0
4
Temp. °C
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
Min
Typ
0.6
0.8
0.9
0.6
0.8
0.9
Max
1.5
4.6
2.0
5.2
2.2
5.5
1.5
4.6
2.0
5.2
2.2
5.5
12
15
35
40
50
60
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Unit
µA
µA
µA
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EM3027
Parameter
Dynamic current
SPI Interface
Low supply detection
level1
Low supply detection
level2
Switchover hysteresis
Symbol
IDD
Vlow1
Vlow2
Test Conditions
SCK = 200 kHz
(See Note 2)
SCK = 1 MHz
(See Note 2)
SCK = 1 MHz
(See Note 2)
Relative to VCC
VCC
1.4
3.3
5.0
Relative to VCC
Temp. °C
-40 to 85
-40 to 125
-40 to 85
-40 to 125
-40 to 85
-40 to 125
Min
-40 to 125
-40 to 125
Max
14
18
50
55
65
75
Unit
1.8
2.1
V
1.0
1.4
V
Vhyst
VCC with respect to VBack =
3.0V
1.4 to 5.0
Input Parameters
Low level input voltage
High level input voltage
VIL
VIH
CS, CLKOE, SI, SCL/SCK,
SDA
1.4 to 5.0
Input Leakage
IIN
0.0 < VIN < VCC
1.4 to 5.0
-40 to 85
-40 to 125
1.4
-40 to 125
3.3
-40 to 125
5.0
-40 to 125
1.4 to 5.0
-40 to 85
-40 to 125
-1
-1.5
-40 to 125
-40 to 85
-40 to 125
1.2
Output Parameters
Low level output voltage
High level output
voltage
Low level output voltage
High level output
voltage
Low level output voltage
High level output
voltage
Output HiZ leakage on
INT
Oscillator
Start-up voltage
Start-up time
VOL
IOL = 0.4 mA
VOH
IOH = 0.1 mA
VOL
IOL = 1.5 mA
VOH
IOH = 1.5 mA
VOL
IOL = 5.0 mA
VOH
IOH = 2.0 mA
ILEAK_OUT
INT not active
VSTA
TSTA
Frequency stability over
voltage
Δf/(f ΔV)
Input capacitance on X1
CIN
Output capacitance
on X2
Trickle Charger
Current limiting
Resistors
COUT
R80k
R20k
R5k
R1.5k
Typ
-40 to 125
20
mV
0.2VCC
0.8VCC
-1
-1.5
µA
1
1.5
V
µA
0.2
V
1.0
0.25
V
2.7
0.8
TSTA < 10s
5.0
1.8V ≤ VCC ≤ 5.5V, TA =
+25°C
TA = +25°C, f = 32.768kHz,
Vmeas = 0.3V (Note 3)
TA = +25°C, f = 32.768kHz,
Vmeas = 0.3V (Note 3)
V
4.5
1
1.5
µA
0.5
1
3
3
V
s
s
25
0.5
2
ppm/
V
25
13.5
25
13.5
25
25
25
25
80
20
5.0
1.5
-40 to 85
-40 to 125
+/- 1
+/- 1
pF
VCC =5.0V, VBack=3.0V
VCC =5.0V, VBack=3.0V
VCC =5.0V, VBack=3.0V
VCC =5.0V, VBack=3.0V
kΩ
Thermometer
Precision
TE
Vlow1 < VCC ≤ 5.5V
+/- 3
+/- 6
Table 7
The following parameters are tested during production test: IDD, Vlow1, Vlow2, VIL, VIH, VOL, VOH, IIN, ILEAK_OUT
The parameters ICC, Vhyst, VSTA, TSTA, CIN, COUT, Δf/(f*ΔV), TE are characterised during the qualification of the IC.
Notes:
1. SDA = VSS, continuous clock applied at SCL (VIL_SCL < 0.05V, VIH_SCL > 0.95VCC)
2. CS, SI = VCC, continuous clock applied at SCK, SO not connected. (VIL_SCK < 0.05VCC, VIH_SCK > 0.95VCC)
Note that there is a 100kΩ pull-down resistor on CS.
3. Vmeas : Peak to peak amplitude during capacitance measurement
Copyright © 2009, EM Microelectronic-Marin SA
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EM3027
4
EM3027 Block Diagram and Application Schematic
4.1
Block Diagram
Switchover
VBack
VHigh
Voltage
Regulator
Voltage
Monitoring
Vcc
Vss
VREG
X1
Xtal
Oscillator
Prescaler
RTC
X2
RAM
32.768 kHz
EEPROM
Control
SCL/SCK
SI
I2C
SPI
Inputs
Stages
CS
SDA/SO
Thermometer
Output
Buffers
CLKOE
SDA/SO INT
4.2
CLKOUT
Application Schematic
Crystal Layout Example
VCC Supply
CD
X1
VCC
for application use
X1
CLKOUT
Crystal
X2
VCC
EM3027
CLKOE
INT
VBack
Protection
Resistor *
X2
CS,
SCL/SCK
SDA/SO
SI
CD
Lithium
Battery
or
Super
Cap
VSS
µController
Serial
Interface
VSS
VSS = 0V
* optional for Lithium batteries (<1kΩ)
Figure1: Application Schematic
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EM3027
4.3
Crystal Thermal Behaviour
The frequency of the crystal is dependent on the
temperature concurring with the following diagram:
The following formula expresses a compensation value
to be used during frequency correction.
0
ΔF
[ppm]
FO
COMP_val = Qcoef × (T − To)
-100
-200
-400
T O-50
TO
T O+50
T O+100
T [°C]
Temperature [°C]
− XtalOffset
2
Qcoef
T
TO
XtalOffset
– Thermal quadratic coefficient [ppm/°C ]
– Actual temperature [°C]
– Turnover temperature [°C]
– Crystal offset at TO [ppm]
COMP_val
– Compensation value result [ppm]
The oscillator frequency is adjusted according to the
equation above by using coefficients located in the
EEPROM control page and the temperature.
The actual temperature can be obtained from the internal
thermometer or from Temp register updated externally by
an application.
The principle of the frequency compensation is based on
adding/removing of pulses.
-300
TO-100
2
Figure 1: Crystal thermal behaviour
TO – Turnover temperature [°C]
FO – Crystal frequency when TO [Hz]
Example 1: Qcoef=0.035; TO=25; XtalOffset=–100
Example 2: Qcoef=0.035; TO=25; XtalOffset=+100
400
[ppm]
600
[ppm]
300
400
200
100
200
Temperature
0
Temperature
0
-50
-50
0
50
100
0
50
100
150
150
-100
-200
-200
-400
-300
Compensation Value
Compensation Value
Crystal Error
Crystal Error
-400
-600
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EM3027
4.4
Crystal Calibration
In order to compensate temperature dependency of the
used crystal, correct values of XtalOffset, Qcoef and TO
parameters shall be stored in EEPROM Control Page.
User is advised to follow these steps in order to compute
the parameters in a correct way:
5)
2
2
ferr = -c1(T – c2) + c3 or fO = aT + bT + c.
6)
1)
Supply the chip from VCC pin.
2)
Set FD0 = FD1 = ‘0’. Set CLKOE pin to ’1’.
This provides the uncompensated
frequency signal from the crystal oscillator
directly on pin CLKOUT.
3)
Find a quadratic regression of the
measured dependency in form:
Then real values of the searched
parameters can be obtained from the
following relations:
Qcoefreal = c1 = -a,
T0_real = c2 = -b/(2a),
2
XtalOffsetreal = c3 = c – b /(4a).
Measure output frequency fO at different
temperatures (at least five measurements
in equidistant points in the whole desired
temperature range are recommended).
Please note that quartz crystal needs few
minutes to stabilise its frequency at a given
temperature.
7)
The values to be stored in EEPROM
Control Page have to be corrected in the
following way:
Qcoef = 4096*(1.05*Qcoefreal),
T0 = T0_real - 4,
4)
XtalOffset = 1.05*XtalOffsetreal.
Compute frequency deviation ferr of output
frequency fo from the ideal (target)
frequency fL = 32.768Hz in all measured
points as follows:
ferr = (fo-fL)/fo .
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EM3027
5
Memory Mapping
Address
Page
Addr
[6..3]
[2..0]
Hex
Description
Range
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Clk/Int
TD1
TD0
SROn
EERefOn
TROn
TiOn
WaOn
1
0
0
Control Page
00000
000
0x00
OnOffCtrl
001
0x01
IRQctrl
Default
0
0
0
0
0
010
0x02
IRQflags
----
SRF
V2F
V1F
TF
AF
011
0x03
Status
----
SR
VLOW2
VLOW1
100
0x04
RstCtrl
----
000
0x08
Watch Seconds
0 – 59 BCD
Seconds Tens
Seconds Units
001
0x09
Watch Minutes
0 – 59 BCD
Minutes Tens
Minutes Units
pm/2
Hours Units
Default
EEBusy
1
1
0
0
1
SRIntE
V2IntE
V1IntE
TIntE
AIntE
PON
SYSRes
Watch Page
00001
0 - 23 BCD
1 - 12 BCD
010
0x0A
Watch Hours
011
0x0B
Watch Date
1 – 31 BCD
100
0x0C
Watch Days
1 – 7 BCD
101
0x0D
Watch Months
1 – 12 BCD
110
0x0E
Watch Years
0 – 79 BCD
000
0x10
Alarm Seconds
0 – 59 BCD
01
0x11
Alarm Minutes
0 – 59 BCD
S12/24
Hours Tens
Date Units
Date Tens
Days Units
Months
Tens
Months Units
Years Tens
Years Units
SecEq
Seconds Tens
Seconds Units
MinEq
Minutes Tens
Minutes Units
0 - 23 BCD
1 - 12 BCD
HourEq
pm/2
Hours Units
Alarm Page
00010
010
0x12
Alarm Hours
011
0x13
Alarm Date
1 – 31 BCD
DateEq
100
0x14
Alarm Days
1 – 7 BCD
DayEq
Hours Tens
Date Tens
Date Units
Days Units
Months
Tens
Months Units
101
0x15
Alarm Months
1 – 12 BCD MonthEq
110
0x16
Alarm Years
0 – 79 BCD
YearEq
000
0x18
Timer low byte
0-255
-
-
-
-
-
-
-
-
001
0x19
Timer high byte
0-255
-
-
-
-
-
-
-
-
0x20
Temp
-60-195 °C
-
-
-
-
-
-
-
-
Years Tens
Years Units
Timer Page
00011
Temperature Page
00100
000
EEPROM Data Page - Configuration Registers
00101
000
0x28
001
0x29
EEData
----
EEPROM user data (2 bytes)
EEPROM Control Page - Configuration Registers
EEctrl
00110
000
0x30
XtalOffset
001
0x31
Qcoef
010
0x32
011
0x33
TurnOver
----
R80k
R20k
R5k
R1.5k
FD1
FD0
ThEn
ThPer
Default
0
0
0
0
0
0
1
0
±121
sign
-
-
-
-
-
-
-
Default
-
-
-
-
-
-
-
-
----
-
-
-
-
-
-
-
-
Default
-
-
-
-
-
-
-
-
4-67 °C
-
-
-
-
-
-
Default
-
-
-
-
-
-
RAM Page (User data RAM)
00111
000-111
0x380x3F
RAMdata
----
8 bytes of data
Table 8
Unused bit (Read as zero; write has no influence)
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EM3027
Notes and Settings:
- Only pages 0 to 7 are used. Unused pages are for test purposes. The application should not write into unused
pages and addresses.
- The crystal offset must be set to within ± 121 ppm.
- Zero values are read from unused addresses.
- Watch, Alarm, Timer pages have to be set by an application before use.
- The bit 7 (MSB) of the Alarm registers (SecEq, MinEq.) have to be set to ‘1’ to perform the comparison. (See
paragraph 8.3)
6
Definitions of terms in the memory mapping
Control Page - Register OnOffCtrl
Clk/Int
TD0, TD1
SROn
EERefOn
TROn
TiOn
WaOn
Selects if clock or interrupt is applied onto the IRQ/CLKOUT pin (’0’ = IRQ output; ’1’ = CLKOUT
output) – CLKOUT output is the default state after reset
Selects decrement rates for Timer (32 Hz after reset)
Enables Self-Recovery function (ON after reset)
Enables Configuration registers refresh each 1 hour (ON after reset)
Enables Timer Auto-reload mode (‘0’ – reload disabled; ‘1’ – reload enabled)
Enables Timer (OFF after reset)
Enables 1 Hz clock for Watch (ON after initialisation)
Control Page - Register IRQctrl
SRIntE
V2IntE
V1IntE
TIntE
AIntE
Self-Recovery interrupt enable
VLOW2 interrupt enable
VLOW1 interrupt enable
Timer interrupt enable
Alarm interrupt enable
Control Page - Register IRQflags
SRF
Self-Recovery interrupt flag (bit is set to ‘1’ when Self-Recovery reset is generated)
V2F
VLOW2 interrupt flag (bit is set to ‘1’ when power drops below Vlow2)
V1F
VLOW1 interrupt flag (bit is set to ‘1’ when power drops below Vlow1)
TF
Timer interrupt flag (bit is set to ‘1’ when Timer reaches ZERO)
AF
Alarm interrupt flag (bit is set to ‘1’ when Watch matches Alarm)
NOTE: Flags can be cleared by ‘0’ writing.
Control Page - Register Status
EEBusy
PON
SR
VLOW2
VLOW1
EEPROM is busy (bit is set to ‘1’ when EEPROM write or Configuration Registers refresh is in
progress) (Read Only)
Power ON (bit is set to ‘1’ at Power On; clear by ‘0’ writing)
Self-Recovery reset or System reset detected (clear by ‘0’ writing)
Voltage level VCC or VBack below Vlow2 level (clear by ‘0’ writing)
Voltage level VCC or VBack below Vlow1 level (clear by ‘0’ writing)
Control Page - Register RstCtrl
SYSRes
System reset register; writing ‘1’ will initiate restart of the logic (Watch, Alarm and Timer parts
excluded). After the restart, status bit SR is set. The register is cleared after restart of the logic.
Watch Page - Registers Watch Seconds, Watch Minutes, Watch Hours, Watch Date, Watch Days, Watch Months,
Watch Years
Watch information (BCD format)
S12/24
12-hours or 24-hours format selection; 12-hours: S12/24 = ‘1’, 24-hours: S12/24 = ‘0’
PM/2
S12/24 = ‘0’ PM/2 represents value ‘2’ of tens,
S12/24 = ’1’ PM/2 = ‘1’ represents PM (afternoon), PM/2 =’0’ represents AM (morning)
Alarm Page - Registers Alarm Seconds, Alarm Minutes, Alarm Hours, Alarm Date, Alarm Days, Alarm Months,
Alarm Years
Alarm information (BCD format)
PM/2
S12/24 = ‘0’ PM/2 represents value ‘2’ of tens,
S12/24 = ’1’ PM/2 = ‘1’ represents PM (afternoon), PM/2 =’0’ represents AM (morning)
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EM3027
Timer Page - Registers TimLow, TimHigh
TimLow
TimHigh
Timer value (Low byte)
Timer value (High byte)
Temperature Page - Register Temp
Temp
Temperature (range from -60° C to 190°C with 0°C corresponding to a content of 60d)
EEPROM Data Page - Register EEData
EEData
General purpose EEPROM data bytes
EEPROM Control Page - Register EEctrl
R80k, R20k,
R5k, R1.5k
FD0, FD1
ThEn
ThPer
Selects trickle charger resistors between VHigh and VBack
Selects clock frequency at IRQ/CLKOUT pin.
Enables thermometer (‘0’ = disabled; ‘1’ = enabled)
Selects thermometer activation period (‘0’ = 1 second; ‘1’ = 16 seconds)
EEPROM Control Page - Register XtalOffset
XtalOffset
Crystal frequency deviation at Turnover temperature TO in ppm. Example: value 63d is related to
60 ppm.
XtalOffset=1.05*XtalOffsetreal
where XtalOffsetreal is real value of crystal frequency deviation at Turnover temperature of the used crystal in ppm.
Note: Coefficient 1.05 (exactly 1.048576) is the result of the internally used frequency compensating method.
EEPROM Control Page - Register Qcoef
Qcoef
Thermal quadratic coefficient of the crystal. Example: value 151d is related to 0.035 ppm/°C²,
Qcoef = 4096 x 1.05 x QCoefreal,
where Qcoefreal is real value of thermal quadratic coefficient of the crystal in ppm/°C².
EEPROM Control Page - Register TurnOver
TurnOver
Turnover temperature of the crystal (values 0 to 63d are related to temperature 4 to 67 °C).
Example: value 21d is related to 25°C.
T0 = T0_real – 4,
where T0_real is real value of Turnover temperature of the crystal in °C.
RAM Page - Register RAMdata
RAMdata
General purpose RAM data bytes
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EM3027
7
Serial communication
Depending on the EM3027 version, the serial communication is performed in I2C or SPI mode.
When the “Transmission START” is detected, a copy of
the content of the addressed Watch-, Alarm-, Timer- and
Temperature-register is stored into a cache memory.
Data for a following read access are provided from this
cache memory.
Data in the cache memory are stable until the “Transmission STOP”.
A serial communication with the EM3027 starts with a
“Transmission START” and terminates with the
“Transmission STOP”.
“Transmission START”
I2C
– START condition
SPI
– CS goes to ‘1’
During a write access, data are written into the cache
memory.
When the “Transmission STOP” of a WRITE transmission is detected, the content of modified registers in
the cache memory is copied back into the Watch-, Alarm,
Timer- and/or Temperature-register.
“Transmission STOP”
I2C
– STOP condition
SPI
– CS goes to ‘0’
7.1
How to perform data transmission through I2C
The I2C protocol is a bidirectional protocol using 2 wires
for master-slave communication: SCL (clock) and SDA
(data). The two bus lines are driven by open drain
outputs and pulled up externally. MSB is sent first.
In the EM3027, the upper 5 bits of a register address
form a “page address”, the 3 lower bits are an autoincrementing sub-address. The “page-address” is defined
by a WRITE transmission. During a transmission, the 3
lower address bits are internally incremented after each
data byte.
The communication is controlled by the master. To start
a transmission, the master applies the START condition
and generates the SCL clocks during the whole
transmission. The master terminates the transmission by
sending the STOP condition.
At a READ transmission (R/W = 1), the slave sends data
and the master gives the ACK bit(s). The “page-address“
shall be defined by a WRITE transmission, completed
with the STOP condition.
The first byte contains the 7 bit slave address and the
R/W bit. The slave address must correspond to the fixed
slave address of the EM3027. After each byte, the
receiver outputs an acknowledge bit ACK to confirm
correct recept of the byte by a ‘0’ level.
The 3 lower address bits are incremented when an ACK
is received.
If ACK is not received, no auto-increment of the address
is executed and a following read outputs data of the
same address.
At a WRITE transmission (R/W = 0), the master sends
slave address, register address and data bytes.
The EM3027 works as slave. Its slave address is fixed to
‘1010110’.
I2C: Write transmission
S
Slave
Address
R/W
1010110
0
ACKs
Address
ACKs
Data Byte
(1)
ACKs
Data Byte
(n-1)
ACKs
Data Byte
(n)
ACKs
P
Data
byte
(n)
ACKm
P
I2C: Read transmission
S
Slave
Address
R/W
1010110
0
S
ACKs
ACKm
...
...
...
Slave
Address
ACKs
Address
ACKs
P S 1010110
start condition sent by the master
acknowledge from the receiver (slave)
acknowledge from the receiver (master)
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
R/W
R/W
P
12
1
...
...
ACKs
Data
byte
(1)
ACKm
read/write select (‘0’: master writes data)
stop condition
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EM3027
A6
SDA
A5
A1
A0 R/W ACK
D7
D6
D2
D1
D0
ACK
Data Byte, send/receive as
many as needed
Slave Address
Read/Write selection bit
1
2
6
7
8
1
9
2
6
7
8
9
SCL
Stop Condition
Start Condition
Figure 2: I2C Communication
Noise suppression circuitry is implemented rejecting spikes shorter than 50ns on SCL and SDA bus lines.
7.2
How to perform data transmission through SPI
The SPI interface connects master and slave circuits.
4 connections are used: CS = Chip Select, SCK = Serial
Clock, SI = Serial Data Input and SO = Serial Data
Output.
SPI is a byte oriented protocol with MSB first mode. Data
are changing on SCK falling edge and sampled on rising
edge.
A transmission is started by the master by rising the CS
input of the selected slave to ‘1’. The transmission is
terminated by the master by putting ‘0’ level the CS input.
The first bit is the R/W bit, R/W = ‘0’ means a WRITE
transmission, where the master sends the data via the SI
line. R/W = ‘1’ defines a READ transmission, where the
slave outputs the data on the SO line.
During a WRITE transmission, the master defines the
register address and sends then data bytes, using the
auto-increment of the lower address part (bit 2 to 0)
within the EM3027.
The page address is fixed until a new transmission is
started.
SO data output of EM3027 is in Hi-Z state during the
WRITE transmission.
If READ transmission is initiated, data are output after
the address byte by the EM3027.
The lower part of the address (bit 2 to 0) is automatically
incremented after each data byte. The page address is
not changed until a new transmission is started.
The following 7 bits of the first byte form the address of
the register in the EM3027, where the data are written or
read. (MSB is first bit at position 2 in this address byte.)
th
The not transmitted 8 bit of the register address is set
internally to ‘0’.
SO is in Hi-Z while the address byte is sent. During data
output by SO, the SI input has no influence.
In the EM3027, the upper 5 bits of an address form a
“page address”, the 3 lower bits are an auto-incrementing
sub-address. The “page-addres’’ is defined by a WRITE
transmission. During a transmission, the 3 lower address
bits are incremented internally after each byte.
SO and SI can be connected together to form a 3-wire
interface with CS, SCK and Serial Data Input/Output.
Copyright © 2009, EM Microelectronic-Marin SA
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When CS is at ‘0’ level, SO is Hi-Z and SCK, SI can be
left floating.
The EM3027 works as slave. The CS input has a pulldown resistor of 100 kΩ.
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EM3027
Transmission Start
Transmission Stop
CS
SCK
SI
R/W
A6
A5
A4
A3
A2
A1
A0
D7
D6
D1
D0
HiZ
SO
Figure 3: SPI Write Transmission
Transmission Start
Transmission Stop
CS
SCK
SI
SO
R/W
A6
A5
A4
A3
A2
A1
A0
HiZ
D7
D6
D1
D0
HiZ
Figure 4: SPI Read Transmission
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EM3027
8
Functional Description
8.1
Start after power-up
A The chip is in reset state when the supply voltage is below an internal threshold level (PON in Status register 0x03 goes
to ‘1’). When the supply level is higher than this threshold voltage, the reset is released.
B When the supply voltage is higher than the oscillator start-up voltage, the basic clocks for Watch and control logic
become active after the oscillator start time.
C With clocks present, the voltage detector starts in fast mode to measure the supply voltage. When a voltage higher than
Vlow2 is detected, the fast detection mode is stopped and the EEPROM read is enabled.
D Configuration registers are loaded with the configuration data read from the EEPROM (Addresses from 0x28 to 0x33).
E If thermometer is enabled (ThEn=’1’ and VLOW1=’0’), temperature is measured and compensation value for frequency
correction evaluated.
F The EM3027 starts its normal function, depending on the supply voltage level applied.
8.2
Normal Mode function
The chip has following functions in Normal Mode:
8.3
1.
Voltage detection – The voltage detection is executed each second.
2.
Temperature measurement – It is executed, if thermometer is enabled (ThEn=’1’) and VLOW1=’0’.
3.
Frequency compensation – The compensation of the oscillator frequency works continuously.
4.
Configuration Registers refresh – The EEPROM is read each hour to refresh the content of the configuration
registers (supply voltage must be above Vlow2 for EEPROM read).
5.
Watch/Alarm – The Watch function is continuously active, whereas the Alarm function depends on its activation.
6.
Timer – Is active when enabled.
7.
Self-Recovery system – Is enabled by default (can be disabled by the application).
8.
Serial interface – The communication works if VCC > VCC_min and VCC > VBack .
Watch and Alarm function
The Watch part provides timing information in BCD format. The timing data is composed of seconds, minutes, hours, date,
weekdays, months and years. The corresponding values are updated every second.
The Watch part setup is provided by Write transmission into the Watch Page (Address 0x08h to 0x0Eh). After the
transmission, the Watch is restarted from the setup values after one second.
The Alarm function is activated by setting and enabling the alarm registers (Address 0x10h to 0x16h). Each Alarm byte has
its own enable bit. It is the bit 7. Recommended combinations of enabled bits are described in the table below.
SecEq
1
1
1
1
1
1
MinEq
0
1
1
1
1
1
HrsEq
DateEq DaysEq MonthEq
0
0
0
0
0
0
0
0
1
0
0
0
1
1
0
0
1
1
0
1
1
0
1
0
Table 9: Alarm Period Selection
YearEq
0
0
0
0
0
0
Al_period
min
hrs
day
month
year
week
- Both Watch and Alarm parts must be set by an application before use
- The bits SecEq to YearEq enable the comparison of the corresponding registers
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EM3027
8.4
Timer function
The 16-bit count down timer can be enabled/disabled by TiOn bit.
The timer input frequency is selected by TD1, TD0 bits according to the following table:
TD1
TD0
Timer frequency
0
0
32 Hz
0
1
8 Hz
1
0
1 Hz
1
1
0.5 Hz
Table 10: Timer Frequency Selection
The timer can run in Zero-Stop or Auto-Reload mode (TROn bit: ‘0’ = Zero-Stop mode, ‘1’ = Auto-Reload mode).
When TROn = ‘0’, then it is possible to read current value of the timer. If TROn = ‘1’, then last written value is read from
cache memory. The value in the cache memory is used as the new value for reloading (Auto-Reload mode).
Frequency selection (TD1, TD0) and mode selection (TROn) can be written only when the timer is stopped (TiOn = ‘0’).
Timer values (TimLow, TimHigh) can be written only when TiOn = ’0’ and TROn = ‘0’.
NOTE: The “Timer Page” can also be used as a general purpose register when the timer function is not used.
8.5
Temperature measurement
The integrated thermometer has a resolution of 1°C.
The thermometer is disabled when ThEn = ’0’ and enabled when ThEn = ’1’. By default, the thermometer is enabled.
Thermometer period is selectable by ThPer bit according to the table below:
ThPer
Period in Seconds
0
1s
1
16 s
Table 11: Thermometer Period
The thermometer is automatically disabled when VLOW1 status bit is at ‘1’.
When the thermometer is disabled (ThEn = ’0’), the Temp register can be written. Temp register uses a cache memory to
keep stable value during a whole transaction (read/write).
8.6
Frequency compensation
There is a frequency compensation unit (FCU) inside EM3027. FCU compensates quartz crystal native frequency in
dependency on actual compensation value (COMP_val).
FCU is always running.
During chip power-up, if ThEn = ’1’ and VLOW1 = ‘0’ temperature measurement is enabled and COMP_val is computed.
Otherwise, COMP_val is set to 0 ppm.
In Normal mode, new compensation value is computed each 32 seconds. The only exception is when ThEn = ‘1’ and
VLOW1 = ‘1’. In this case, temperature measurement and COMP_val computation are blocked and FCU uses the last
computed compensation value.
For the evaluation of COMP_val, actual content of Temp register (0x20) is used. The compensation value is computed
according to the equation described in paragraph 4.3.
Content of Temp register is updated either after a temperature measurement (when ThEn = '1' and VLOW1 = '0') or after
Temp register write transaction (when ThEn = '0'). After power-up content of Temp register is undefined.
If thermometer is disabled (ThEn = '0') user is advised to periodically update Temp register with actual ambient temperature
in order to have correct input data for COMP_val computation.
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EM3027
8.7
EEPROM memory
Before any EEPROM access (read/write), the bit EERefOn has to be cleared by the application to prevent from access
collision with the Configuration Registers.
Then the application has to read EEBusy bit and if EEBusy = ‘0’, then EEPROM access can be started.
After the write command (at “Transmission STOP”) the current state of EEPROM writing is monitored by EEBusy register bit
at ‘1’. EEBusy goes to ‘0’ when EEPROM writing is finished.
NOTE: VCC must be applied during the whole EEPROM write (i.e. until EEBusy = ‘0’) and must be higher than Vprog.
Clear EERefOn
Clear EERefOn
No
No
EEBusy = 0 ?
Yes
Yes
Write EEPROM
Read EEPROM
Yes
EEBusy = 0 ?
No
Next read ?
EEBusy = 0 ?
Yes
No
Set EERefOn
Yes
Next Write ?
No
Set EERefOn
8.7.1
EEPROM Control Page
This part is composed of 4 bytes purposed for miscellaneous function control and for crystal compensation constants.
EEctrl byte contains: trickle charger selectors (R80k, R20k, R5k, R1.5k); output clock frequency selector (FD1, FD0);
thermometer enable and thermometer period selector.
8.7.2
Clock Output
Output clock frequency is selected by FD1, FD0 bits in EEctrl register.
FD1
0
FD0
0
0
1
1
1
0
1
Select Clock Output
Description
From crystal oscillator, without
frequency compensation
32.768 kHz
1024 Hz
With frequency compensation
32 Hz
1 Hz
Table 12: Output Clock frequency selection
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EM3027
8.7.3
Configuration Registers
All the configuration data from EEPROM (i.e. EEctrl, XTalOffset, Qcoef, TurnOver, EEData) is hold in configuration
registers.
Data from EEPROM is loaded to these registers during power-up sequence and is refreshed each hour, if ‘Configuration
Registers refresh’ feature is enabled (EERefOn = ‘1’).
Regular refresh of Configuration Registers prevents their content to be corrupted by strongly polluted electrical environment
(EMC problems, disturbed power supply, etc.).
It is recommended to enable ‘Configuration Registers refresh’ feature.
8.7.4
EEPROM User Memory
Two bytes of the memory are dedicated for the application (addresses 0x28 and 0x29).
8.8
RAM User Memory
RAM user memory size is 8 bytes (addresses 0x38 to 0x3F). The state of the RAM data after power-up is undefined.
8.9
Status Register
The purpose of EEBusy bit is to inform the user about current status of the EEPROM operations.
EEBusy – status of EEPROM controller (if EEBusy = ‘1’, then Configuration Registers refresh or EEPROM write is in
progress)
The purpose of the following status bits is to record status of power supply voltage and Self-Recovery system/System reset
behaviour.
PON
VLOW1
VLOW2
SR
– status of Power-ON
– status of Vlow1 voltage detection
– status of Vlow2 voltage detection
– status of the Self-Recovery system/System reset
If one of these status bits is set, it can be cleared only by writing ‘0’, there is no automatic reset if the set condition
disappears.
8.10
Interrupts
There are five interrupt sources which can output an interrupt on (INT and/or IRQ/CLKOUT) pins. The request
is generated when at least one of IRQflags goes to ‘1’ (OR function).
AF
TF
V1F
V2F
SRF
– interrupt is provided when Watch time reaches Alarm time settings and comparison is enabled
– interrupt is provided when Timer reaches ZERO
– interrupt is provided when supply voltage is below Vlow1 (when VLOW1 status bit is set)
– interrupt is provided when supply voltage is below Vlow2 (when VLOW2 status bit is set)
– interrupt is provided when Self-Recovery system invoked internal reset (when SR status bit is set)
Each interrupt source has its own interrupt enable (AIntE, TIntE, V1IntE, V2IntE, SRIntE). When the interrupt enable is ‘1’
then the appropriate interrupt source is enabled.
Interrupt flags (IRQflags) are cleared by ‘0’ writing into the appropriate bit. In case of V1F, V2F and SRF bits, it is necessary
to clear also the corresponding status bits (Status) after interrupt bit.
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EM3027
8.11
Self-Recovery System (SRS)
The purpose of the Self-Recovery System (SRS) is to generate an internal reset in case the on-chip state machine goes
into a deadlock. The function is based on an internal counter that is periodically reset by the control logic. If the counter is
not reset on time, this reset will take place. It is executed after two voltage monitoring periods at the latest, i.e. 2s or 32s
(ThPer bit).
A possible source of a deadlock could be disturbed electrical environment (EMC problem, disturbed power supply, etc.).
SRS sets status bit SR and resets the internal logic, except Watch, Alarm and Timer parts (i.e. time informations are not
affected). Furthermore, if the SRS interrupt is enabled (SRIntE='1'), the SRF flag is set after the internal chip reset. Note,
that SROn = '1' and SRIntE = '0' after the reset.
After the internal reset, the device starts with the power-up sequence (see paragraph 8.1).
SRS is automatically enabled after power-up (SROn bit). It can be disabled by writing '0' into the SROn bit in the Control
Page.
8.12
Register Map
The address range of the EM3027 is divided into pages. The page is addressed by the five most significant bits of the
address (bits 6 … 3). The three low significant bits of the address provide selection of registers inside the page. During
address incrementing the three low significant bits (2 … 0) are changed. The page address part is fixed during the whole
data transmission.
8.13
Crystal Oscillator and Prescaler
The 32.768 kHz crystal oscillator and the clock divider provide the timing signals for the functional blocks. The prescaler
block is responsible for frequency division of the 32.768 kHz clock signal from the crystal oscillator. Divided frequency is
then distributed between other blocks inside the chip, including Watch, Timer and control logic.
Two capacitors CIN and COUT are integrated on chip – see Figure 5.
X2
X1
CIN
COUT
Figure 5: Oscillator Capacitors
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EM3027
9
Power Management
VCC
Switchover
I/O
V H igh
4x Trickle
charger
resistors
V Back
V Reg
Logic, EEPROM,
Thermometer,
Voltage Monitor
Regulator
2.9V
Xtal
Oscillator
Figure 6: Power Management
9.1
Power Supplies, Switchover and Trickle Charger
The device can be supplied from the VCC pin or from the
VBack pin.
In this way, a rechargeable battery or a super-cap can be
charged from the VCC voltage, as long as VCC > VBack.
The switchover block implemented inside the chip
compares VCC and VBack voltages and connects the
higher of them to the internal VHigh net that supplies the
chip.
There are 4 selectable resistors connected in parallel
with typical values of 80kΩ, 20kΩ, 5kΩ and 1.5kΩ. One
or more resistors can be selected by EEctrl bits setting.
Nevertheless, the communication pins (SCL, SDA or CS,
SCK, SI, SO) are supplied from the VCC pin. For that
reason, when serial interface (I2C or SPI) is used, the
chip has to be supplied from VCC. (i.e. VCC > VBack).
By setting of a trickle charger bit in register EEctrl, a
resistor can be inserted between VBack and VHigh voltage.
If a Lithium battery shall be connected to VBack pin, a
protection resistor of value up to 1kΩ can be connected
in series with it. In this way, in case of EM3027 device
damage resulting in short between both supply pins,
charging current from the VCC supply can be reduced to
its allowed maximum level as required by UL1642
standard.
Clock operating with thermocompensation using either
previously in fully operating mode measured or by user
stored temperature value; no EEPROM write
Vlow2
Serial communication
is enabled, if
VCC > VCCmin and
VCC > Vback
min max
Vlow1
min max
Vprog
VCCmin
VCCmax
EEPROM write if VCC > Vprog
1.4V
0V
EM3027 fully operating according datasheet
(clock, thermometer, thermocompensation)
5.5V
2.2V
1.0V
2.0V
3.0V
4.0V
5.0V
Supply Voltage
Figure 7: EM3027 operating Voltage Areas
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EM3027
9.2
Low Supply Detection
The supply voltage level is monitored periodically versus
Vlow1 and Vlow2 levels. The monitoring rate is one
second. When the voltage monitoring is running, a higher
current consumption for few milliseconds occurs.
At the power-up of the device, as long as the supply
voltage stays below Vlow2, the monitoring rate is
accelerated. To enable normal operation, the chip must
be supplied with a voltage above Vlow2, to enable the
readout of initialization data from EEPROM and to stop
the higher current consumption.
When the supply voltage drops from the normal range
(from 2.1V to 5.5V) below Vlow1, the VLOW1 status bit is
set to ‘1’ by the voltage monitoring system.
When bit VLOW1 is at ‘1’, the thermometer is disabled
and the automatic computation of the thermal
compensation value (COMP_val) for frequency
correction is inhibited. In this case, the last computed
compensation value is used.
Copyright © 2009, EM Microelectronic-Marin SA
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To leave the VLOW1 status, the supply voltage must be
increased above the Vlow1 level and a ‘0’ value must be
written into the VLOW1 status bit via the serial interface.
When the supply voltage drops below the Vlow2 level,
the VLOW2 status bit is set by the voltage monitoring
system.
The VLOW2 status bit disables the read out of the
EEPROM.
To leave the VLOW2 status, the supply voltage must be
increased above the Vlow2 level and a ‘0’ value must be
written into the VLOW2 status bit via the serial interface.
Below Vlow2 level, device functionality is not guaranteed
and register contents can be corrupted. Therefore, if
VLOW2 status bit is set, it is recommended to perform
system reset by writing of ‘1’ into SYSRes bit in RstCtrl
page and afterwards update content of Watch, Alarm and
Timer registers.
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EM3027
10 AC Characteristics
10.1 AC characteristics – I2C
VSS = 0V and TA=-40 to +125°C, unless otherwise specified
PARAMETER
SYMBOL
SCL Clock Frequency
fSCL
CONDITIONS
MIN
Hold Time (Repeated) START
Condition
tBUF
MAX
Vcc ≥ 3.0V
400
Vcc >1.8V
300
UNITS
kHz
100
Vcc>1.4V
Bus Free Time Between STOP and
START Condition
TYP
Vcc ≥ 3.0V
0.4
Vcc >1.8V
0.5
Vcc>1.4V
1.0
μs
Vcc ≥ 3.0V
tHD:STA
0.2
Vcc >1.8V
μs
Vcc>1.4V
LOW Period of SCL Clock
HIGH Period of SCL Clock
Setup Time START Condition
Data Hold Time
Data Setup Time
Data Valid Time
Data Valid Acknowledge Time
Rise Time of Both SDA and SCL
Signals
Fall Time of Both SDA and SCL
Signals (See note 1)
tLOW
tHIGH
tSU:STA
tHD:DAT
tSU:DAT
tVD:DAT
tVD:ACK
tR
tF
Vcc ≥ 3.0V
1.3
Vcc >1.8V
1.7
Vcc>1.4V
4.5
Vcc ≥ 3.0V
0.4
Vcc >1.8V
0.5
Vcc>1.4V
0.6
Vcc ≥ 3.0V
20
Vcc >1.8V
30
Vcc>1.4V
50
Vcc ≥ 3.0V
20
Vcc >1.8V
30
Vcc>1.4V
50
Vcc ≥ 3.0V
50
Vcc >1.8V
80
Vcc>1.4V
100
Vcc ≥ 3.0V
1.2
Vcc >1.8V
1.5
Vcc>1.4V
4.0
Vcc ≥ 3.0V
0.9
Vcc >1.8V
1.1
Vcc>1.4V
3.5
tSU:STO
μs
ns
ns
ns
μs
μs
Vcc ≥ 3.0V
200
Vcc >1.8V
300
Vcc>1.4V
1000
Vcc ≥ 3.0V
200
Vcc >1.8V
300
ns
ns
400
Vcc>1.4V
Setup Time (Repeated) STOP
Condition
μs
Vcc ≥ 3.0V
20
Vcc >1.8V
30
Vcc>1.4V
50
ns
Length of spikes suppressed by the
input filter on SCL and SDA
Capacitive Load For Each Bus Line
tSP
50
CB
200
pF
I/O Capacitance (SDA, SCL)
CI/O
10
pF
ns
Table 13: I2C AC characteristics
Parameters are guaranteed by design. They are not tested in production.
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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EM3027
Calculation of external pull–up resistor
The following conditions have to be met:
Rise time is equal to 0.847 RPU (CB + N * CI/O) ⇒ RPU < tR max / (0.847 (CB + N CI/O)), where N is total number of
I/O pins connected to the corresponding bus line.
(tR in ns, C in pF, R in kΩ)
The minimum value of the pullup resistor value can be calculated with the IOL value of the SDA output:
RPU = (Vcc – VOL) / IOL
( IOL: see Table 7, page 5, Output Parameters; e.g. 5mA at VCC = 5.0V, with VOL = 0.8V )
Start
Stop
SDA
tBUF
tHIGH
tLOW
tR
SCL
tHD:STA
tHD:DAT
tF
tSU:STO
tSU:DAT
tSU:STA
Figure 8: I2C Timing
10.2
I2C Specification compliance
EM3027 device with I2C serial interface was designed
2
in compliance with Philips Semiconductors I C-bus
specification UM10204 (Rev. 03 – 19 June 2007), Fastmode class (up to 400kbit/s). Device address consists
of 7 bits. Clock stretching is not supported.
Brief manual to I2C interface read and write
transmissions is to be found in §7.1.
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
There are, however, the following discrepancies between
I2C specification and EM3027 interface:
1)
Falling time on SDA driven by EM3027 can be
shorter than 20 + 0.1* CB ns. (CB is total capacitive
load for SDA bus line in pF) In other words, slope
control of falling edges on SDA is missing.
2)
Some timing parameters differ from the original I2C
specification – refer to Table 13.
23
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EM3027
10.3
AC characteristics – SPI
VSS = 0V and TA=-40 to +125°C, unless otherwise specified
PARAMETER
SYMBOL
CONDITIONS
fSCK
SCK Clock Frequency
Data to SCK setup
tDC
MIN
TYP
MAX
UNITS
Vcc ≥ 3.0V
1
MHz
Vcc >1.8V
600
Vcc >1.4V
200
kHz
Vcc ≥ 3.0V
Vcc >1.8V
20
ns
Vcc >1.4V
SCK to Data Hold
tCDH
SCK to Data Valid
tCDD
SCK Low Time
tCL
SCK High Time
tCH
SCK Rise and Fall
tR , tF
Vcc ≥ 3.0V
200
Vcc >1.8V
300
Vcc >1.4V
500
Vcc ≥ 3.0V
350
Vcc >1.8V
650
Vcc >1.4V
1300
Vcc ≥ 3.0V
400
Vcc >1.8V
700
Vcc >1.4V
1500
Vcc ≥ 3.0V
400
Vcc >1.8V
700
Vcc >1.4V
1500
Vcc ≥ 3.0V
ns
ns
800
Vcc >1.4V
tCC
ns
200
Vcc >1.8V
CS to SCK Setup
ns
ns
Vcc ≥ 3.0V
Vcc >1.8V
100
ns
Vcc >1.4V
SCK to CS Hold
tCCH
CS Inactive Time
tCWL
CS to Output High Impedance
tCDZ
Vcc ≥ 3.0V
200
Vcc >1.8V
300
Vcc >1.4V
500
Vcc ≥ 3.0V
200
Vcc >1.8V
300
Vcc >1.4V
400
Vcc ≥ 3.0V
ns
ns
50
Vcc >1.8V
100
Vcc >1.4V
200
ns
Table 14: SPI AC characteristics
Parameters are guaranteed by design. They are not tested in production.
1) Max. bus capacitance on SO line shall be lower than 100pF when Vcc > 1.8V and lower than 50pF when Vcc < 1.8V.
2) Spikes on SCK signal shorter than 20ns are suppressed.
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
24
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EM3027
CS
tF
tCC
tCH
t
tCCH
tCL
tCWL
SCK
tDC
tCDH
A0
R/W
SI
SI data are don't care when SO outputs data
tCDD
SPI Master writes address, EM3027 outputs data:
HiZ
SO
tCDZ
D0
D7
Figure 9: SPI Read Timing
CS
tF
tCC
tCH
t
tCCH
tCL
tCWL
SCK
tDC
SI
tCDH
R/W
A0
D7
D0
SPI Master writes address and data:
SO
HiZ
Figure 10: SPI Write Timing
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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EM3027
11 Package Information
11.1 TSSOP-08/14
4
B
1.00
1.00 DIA.
3 2 1
C
B
B
E/2
1.00
E
C
L
E1 5
N
0.20 C A-B D
2X N/2 TIPS
e/2
7
4
SEE
DETAIL "A"
D
A 4
b
bbb M C A-B
A2
ODD LEAD SIDES
TOPVIEW
TOPVIEW
D 9
0.05 C
0.25
PARTING
LINE
A
H
C
e
A1
H
D
5
C
aaa
3
X = A AND B
(14°)
EVEN LEAD SIDES
END VIEW
TOP VIEW
X
X
L 6
8
SEATING
PLANE
(1.00)
DETAIL 'A'
(14°)
(VIEW ROTATED 90° C.W.)
S
Y
M
B
O
L
A
A1
A2
aaa
b
b1
bbb
c
c1
D
E1
e
E
L
N
P
P1
COMMON
DIMENSIONS
MIN.
NOM.
0.05
0.85
0.90
0.076
0.19
0.19
0.22
0.10
0.09
0.09
0.127
SEE VARIATIONS
4.30
4.40
0.65 BSC
6.40 BSC
0.50
0.60
SEE VARIATIONS
SEE VARIATIONS
SEE VARIATIONS
0°
NOTE
MAX.
1.10
0.15
0.95
0.30
0.25
0.20
0.16
4.50
0.70
8°
ALL DIMENSIONS IN MILLIMETERS
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
N
VARIO
T
E ATIONS
9
MIN.
2.90
4.90
5
D
NOM.
3.00
5.00
MAX.
3.10
5.10
P
MAX.
1.59
3.1
P1
MAX.
3.2
3.0
7
N
8
14
NOTES:
1. DIE THICKNESS ALLOWABLE IS 0.279±0.0127
2. DIMENSIONING & TOLERANCES PER ASME. Y14.5M-1994.
3. DATUM PLANE H LOCATED AT MOLD PARTING LINE AND COINCIDENT
WITH LEAD, WHERE LEAD EXITS PLASTIC BODY AT BOTTOM OF PARTING LINE.
4. DATUM A-B AND D TO BE DETERMINED WHERE CENTERLINE
BETWEEN LEADS EXITS PLASTIC BODY AT DATUM PLANE H.
5
5
5. "D" & "E1" ARE REFERENCE DATUM AND DO NOT INCLUDE MOLD FLASH OR
PROTRUSIONS, AND ARE MEASURED AT THE BOTTOM PARTING LINE. MOLD
FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.15mm ON D AND 0.25mm
ON E PER SIDE.
6. DIMENSION IS THE LENGTH OF TERMINAL FOR SOLDERING TO A SUBSTRATE.
6
7
7. TERMINAL POSITIONS ARE SHOWN FOR REFERENCE ONLY.
8. FORMED LEADS SHALL BE PLANAR WITH RESPECT TO
ONE ANOTHER WITHIN 0.076mm AT SEATING PLANE.
9. THE LEAD WIDTH DIMENSION DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE
0.07mm TOTAL IN EXCESS OF THE LEAD WIDTH DIMENSION
AT MAXIMUM MATERIAL CONDITION. DAMBAR CANNOT BE
LOCATED ON THE LOWER RADIUS OR THE FOOT. MINIMUM
SPACE BETWEEN PROTRUSIONS AND AN ADJACENT LEAD SHOULD
BE 0.07mm
26
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EM3027
11.2
SO-8
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
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EM3027
12 Ordering Information
EM3027 I D X SO8B
Part Number
EM3027 =
Package
RTC
Interface
SO8B=
8 pin SO8 tape
TP8B=
8 pin TSSOP8 tape
I2C bus =
I
TP14=
14 pin TSSOP14 tape
SPI bus =
S
WS11=
Wafer sawn 11 MILS
Temperature compensation
Functional Temperature
D
Default Temp. Compensation =
Standard temperature= S
Extended temperature= X
(Factory Standard)
Standard Versions
Part Number
Package
EM3027IDSTP8A+
EM3027IDSTP8B+
EM3027IDXTP8B+
EM3027IDSSO08A+
EM3027IDSSO08B+
EM3027IDXSO08B+
EM3027SDSTP14A+
EM3027SDSTP14B+
EM3027SDXTP14B+
TSSOP8
TSSOP8
TSSOP8
SO8
SO8
SO8
TSSOP14
TSSOP14
TSSOP14
Functional
Temperature
-40 +85°C
-40 +85°C
-40 +125°C
-40 +85°C
-40 +85°C
-40 +125°C
-40 +85°C
-40 +85°C
-40 +125°C
Interface
I2C
I2C
I2C
I2C
I2C
I2C
SPI
SPI
SPI
Delivery Form
Marking
Stick , 100 pcs
Tape & Reel, 4000 pcs
Tape & Reel, 4000 pcs
Stick, 97 pcs
Tape & Reel, 2500 pcs
Tape & Reel, 2500 pcs
Stick, 96 pcs
Tape & Reel, 3500 pcs
Tape & Reel, 3500 pcs
3027S5
3027S5
3027X5
3027S5
3027S5
3027X5
3027S6
3027S6
3027X6
Please contact Sales office for other versions not shown here and for availability of non standard versions.
EM Microelectronic-Marin SA (EM) makes no warranty for the use of its products, other than those expressly contained in
the Company's standard warranty which is detailed in EM's General Terms of Sale located on the Company's web site.
EM assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or
specifications detailed herein at any time without notice, and does not make any commitment to update the information
contained herein. No licenses to patents or other intellectual property of EM are granted in connection with the sale of EM
products, expressly or by implications. EM's products are not authorized for use as components in life support devices or
systems.
Copyright © 2009, EM Microelectronic-Marin SA
12/09 – rev D
28
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