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4.13 SVD (Supply Voltage Detection) Circuit
4.13.1 Configuration of SVD circuit
The S1C63558 has a built-in SVD (supply voltage detection) circuit, so that the software can find when the
source voltage lowers. It is possible to check an external voltage drop, other than the supply voltage, by
mask option.
Turning the SVD circuit ON/OFF and the SVD criteria voltage setting can be done with software.
Figure 4.13.1.1 shows the configuration of the SVD circuit.
terminal
4.13.2 Mask option
Besides the supply voltage (V
external voltage (SVD terminal–V
detected voltage (1.05 V). This function can select whether or not to use with the mask option.
4.13.3 SVD operation
The SVD circuit compares the criteria voltage set by software and the supply voltage (V
terminal) or the external voltage (SVD terminal–V
By reading the data of this SVDDT latch, it can be determined by means of software whether the supply
voltage is normal or has dropped.
The criteria voltage can be set for the 12 types shown in Table 4.13.3.1 by the SVDS3–SVDS0 registers.
When "0" is written to the SVDS3–SVDS0 register, the supply voltage detection voltage is set to 2.20 V.
However, when "External voltage detection" is selected by mask option, the SVD circuit does not compare
the supply voltage (V
DD
nal–V
terminal) input from the SVD terminal and 1.05 V.
SS
SVDS3
SVDS2
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
S1C63558 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (SVD Circuit)
V
DD
SVD
SVD circuit
V
SS
Fig. 4.13.1.1 Configuration of SVD circuit
terminal–V
DD
SS
terminal) input from the SVD terminal by comparing it with the
SS
terminal–V
terminal) but compares between the external voltage (SVD termi-
SS
Table 4.13.3.1 Criteria voltage setting
Criteria
SVDS1
SVDS0
voltage ( V )
1
1
2.50
1
0
2.40
0
1
2.30
0
0
2.20
1
1
2.20
1
0
2.20
0
1
2.20
0
0
2.20/1.05
Detection output
SVDDT
SVDON
SVDS3
Criteria voltage
setting circuit
SVDS0
terminal) drop detection, the SVD circuit can detect the
terminal) and sets its results into the SVDDT latch.
SS
SVDS3
SVDS2
1
1
1
1
1
1
1
1
1
0
1
0
1
0
1
0
EPSON
|
terminal–V
DD
Criteria
SVDS1
SVDS0
voltage ( V )
1
1
3.30
1
0
3.20
0
1
3.10
0
0
3.00
1
1
2.90
1
0
2.80
0
1
2.70
0
0
2.60
SS
109
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