em3027 EM Microelectronic, em3027 Datasheet - Page 17

• Manufacturer Part Number: em3027
• Description: Real-time Clock With I2c Or Spi Interface, Crystal Temperature Compensation, Battery Switchover And Trickle Charger
• Manufacturer: EM Microelectronic

8.7.1
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
Output clock frequency is selected by FD1, FD0 bits in EEcrtl register.
8.7.3
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
One byte of the memory is dedicated for the application.
8.8
RAM memory size is 8 bytes. The state of RAM data part after power-up is undefined.
Copyright © 2008, EM Microelectronic-Marin SA
07/08 – rev B
Yes
No
RAM User Memory
EEPROM Control Page
Clock Output
Configuration Registers
EEPROM User Memory
R
Next read ?
Read EEPROM
EEBusy = 0 ?
Set EERefOn
Clear EERefOn
FD1
0
0
1
1
Yes
No
FD0
0
1
0
1
Table 12 – Output Clock frequency selector
Select Clocks Out
32768 Hz
1024 Hz
32 Hz
1 Hz
17
Yes
Description
No
No
Crystal Oscillator without correction
Compensated frequency
Write EEPROM
Set EERefOn
EEBusy = 0 ?
EEBusy = 0 ?
Clear EERefOn
Next Write ?
No
Yes
Yes
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EM3027