R01UH0823EJ0100 Rev.1.00 Page 250 of 1823
Jul 31, 2019
RX23W Group 12. Battery Backup Function
12.2 Register Descriptions
12.2.1 VBATT Control Register (VBATTCR)
Note: Set the PRCR.PRC3 bit to 1 (write enabled) before rewriting this register.
The VBATTCR register is used to control operation of the battery backup function.
VBATTDIS Bit (Battery Backup Function Disable)
This bit is used to enable or disable the function for switching the power supply to the backup power area from VCC
supply to battery backup power pin (VBATT pin) supply when the voltage at the VCC drops.
When the battery backup function is not used, set the VBATTDIS bit to 1 (battery backup function disabled).
VBTLVDEN Bit (VBATT Pin Voltage Drop Detection Enable)
This bit is used to enable or disable the voltage drop detection function of the VBATT pin.
VBTLVDLVL[1:0] Bits (VBATT Pin Voltage Drop Detection Level Select)
These bits are used to select the detection voltage level (Vdetvbt) when the voltage drop detection function of the
VBATT pin is enabled.
VBTLVDLVL bits are enabled when the VBATTCR.VBATTDIS bit is 0 (battery backup function enabled).
Address(es): 0008 C29Dh
b7 b6 b5 b4 b3 b2 b1 b0
VBTLVDLVL[1:0] —
VBTLV
DEN
———
VBATT
DIS
Value after reset:
00000000
Bit Symbol Bit Name Description R/W
b0 VBATTDIS Battery Backup Function
Disable
0: Battery backup function enabled
1: Battery backup function disabled
R/W
b3 to b1 — Reserved These bits are read as 0. The write value should be 0. R/W
b4 VBTLVDEN VBATT Pin Voltage Drop
Detection Enable
0: VBATT pin voltage drop detection disabled
1: VBATT pin voltage drop detection enabled
R/W
b5 — Reserved This bit is read as 0. The write value should be 0. R/W
b7, b6 VBTLVDLVL[1:0] VBATT Pin Voltage Drop
Detection Level Select
b7 b6
1 0: 2.20 V
1 1: 2.00 V
Settings other than above are prohibited.
R/W
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