RV-3029 Datasheet, PDF (35/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
4.7. WATCH ENABLE FUNCTION
The function Watch Enable function “WE” (bit 0 in register Control_1) enables / disables the 1 Hz clock for the
watch function. After power-up reset, the bit “WE” is automatically set = “1” and the 1 Hz clock is enabled.
Setting “WE” = “0” stops the watch-function and the time circuits can be set and will not increment until the stop is
released. Setting “WE” = “1” allows for accurate start of the time circuits triggered by an external event.
“WE” will not affect the clock outputs at CLKOUT.
4.8. SELF-RECOVERY SYSTEM
The purpose of the Self-Recovery System is to automatically generate an internal Reset in case the on-chip state
machine goes into a deadlock. A possible source for such a deadlock could be disturbed electrical environment like
EMC problem, disturbed power supply or any kind of communication issues on the I²C interface.
The function of the Self-Recovery System is based on internal counter that is periodically reset by the Control
Logic. If the counter is not reset in time, a Self-Recovery Reset will be executed, at the latest after 2 thermometer
scanning interval periods, i.e. 2 or 32 seconds.
The Self-Recovery System is enabled / disabled by “SROn ” (bit 4 in register Control_1), it is automatically enabled
“SROn” = “1” after power-up by the register reset values, see section 4.2.2. REGISTER RESET VALUES.
Thermometer scanning interval is defined with “ThP” (bit 0 in register EEPROM_Control).
Generation of Interrupts from the System Reset function is enabled via “SRIE” = “1” (bit 4 in register Control_INT).
If “SRIE” is enabled, the INT follows the condition of Flag “SRF” (bit 4 in register Control_INT Flag). To clear
Interrupt signal ( INT ), both corresponding flags “SRF” (bit 4 in register Control_INT Flag) and “SR” (bit 4 in register
Control_Status) need to be cleared by writing = “0”.
During Self-Recovery or System Reset, the internal logic is reset and registers are loaded with the Register Reset
Values shown in section 4.2.2., Watch / Alarm and Timer information are not affected.
After Self-Recovery Reset, “SRF” is set = “1” (bit 4 in Register Control_INT Flag), indicating that an automatic
Self-Recovery System Reset has been executed.
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