RX8900 SA / CE
Page - 25 ETM45E-01
8.8.2. Control the contents of the power switching
1) BACKUP state
PMOS switch is turned off at all times. Voltage detection VDET3 is responsible for monitoring every 1sec.
This state will be selected at cold start.
Make the voltage detection for the first time in 1sec after since it was powered on
VDD pin.
Until voltage detection for the first time, VBAT is charged in the forward current of the PMOS switch.
In this state, the (VDET3 = L → H), main power supply (VDD) shifts to the NORMAL state of the drive state when it
detects a rise VDET level.
Return of the main power supply is detected, the internal voltage supply of the RTC will
transition to NORMAL state.
2) NORMAL state
PMOS switch is turned off in every 1sec , power drop is detected in the off timing of the switch.
Off time of the switch can be selected in the register.
Drop of the main power supply is detected, an internal power supply voltage of the RTC will be backed up state
transitions.
8.8.3. Function that can be used in the backup state
When operating in the backup, please VDD = VSS= 0V.
Function Available
/Not available
Remarks
Interface Not available Interface circuit can not operate.
Clock calendar Available The same as the main power supply operation
Alarm interrupt Available You can not use the interrupt output function.
Timer interrupt Available You can not use the interrupt output function.
Time update interrupt Available You can not use the interrupt output function.
Clock output Not available There is no output from terminal Fout pin.
VBAT Voltage drop detection Available The same as the main power supply operation
Temperature Compensation Available This function is Available when VBAT supply voltage is more than 2.0V
To Next Page
Loading...
