Datasheet

Section 20 Power-On Reset and Low-Voltage Detection Circuits (Optional)
Rev. 3.00 Mar. 15, 2006 Page 393 of 526
REJ09B0060-0300
20.2 Register Descriptions
The low-voltage detection circuit has the following registers.
• Low-voltage-detection control register (LVDCR)
• Low-voltage-detection status register (LVDSR)
20.2.1 Low-Voltage-Detection Control Register (LVDCR)
LVDCR is used to enable or disable the low-voltage detection circuit, set the detection levels for
the LVDR function, enable or disable the LVDR function, and enable or disable generation of an
interrupt when the power-supply voltage rises above or falls below the respective levels.
Table 20.1 shows the relationship between the LVDCR settings and select functions. LVDCR
should be set according to table 20.1.
Bit Bit Name
Initial
Value R/W Description
7 LVDE 0* R/W LVD Enable
0: The low-voltage detection circuit is not used (In
standby mode)
1: The low-voltage detection circuit is used
6 to 4  All 1  Reserved
These bits are always read as 1, and cannot be
modified.
3 LVDSEL 0* R/W LVDR Detection Level Select
0: Reset detection voltage is 2.3 V (typ.)
1: Reset detection voltage is 3.6 V (typ.)
When the falling or rising voltage detection interrupt is
used, reset detection voltage of 2.3 V (typ.) should be
used. When only a reset detection interrupt is used,
reset detection voltage of 3.6 V (typ.) should be used.
2 LVDRE 0* R/W LVDR Enable
0: Disables the LVDR function
1: Enables the LVDR function