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:
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
.
8.3
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
MinEq
HrsEq
DateEq DaysEq MonthEq YearEq Al_period
1
1
1
1
1
1
0
1
1
1
1
1
0
0
1
1
1
1
0
0
0
1
1
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
min
hrs
day
month
year
week
Table 9: Alarm Period Selection
- 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
15
www.emmicroelectronic.com
Copyright 2013, EM Microelectronic-Marin SA
3027-DS.doc, Version 8.0, 25-Jan-13
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
