Section 19 Band-Gap Circuit, Power-On Reset, and Low-Voltage Detection Circuits
19.2
Register Descriptions
The low-voltage detection circuit has the following registers.
•
•
•
Low-voltage-detection control register (LVDCR)
Low-voltage-detection status register (LVDSR)
Reset source decision register (LVDRF)
19.2.1
Low-Voltage-Detection Control Register (LVDCR)
LVDCR selects the compared voltage of the LVDI circuit, sets the detection levels for the LVDR
circuit, enables or disables the LVDR circuit, and enables or disables generation of an interrupt
when the power-supply voltage rises above or falls below the respective levels.
Table 19.1 shows the relationship between the LVDCR settings and functions to be selected.
LVDCR should be set according to table 19.1.
Initial
Bit
Bit Name Value
R/W
Description
7, 6
All 1
Reserved
These bits are always read as 1 and cannot be modified.
LVDR External Compared Voltage Input Inhibit
0: Use external voltage as LVDI compared voltage
1: Use internal voltage as LVDI compared voltage
Reserved
5
VDDII
1*1
R/W
4
3
1
1
This bit is always read as 1 and cannot be modified.
LVDR Detection Level Select
LVDSEL*2
R/W
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, the 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
1
Reserved
This bit is always read as 1 and cannot be modified.
Rev. 3.00 Sep. 10, 2007 Page 382 of 528
REJ09B0216-0300
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