Epson S1C17624 Technical Manual page 288

26 Supply Voltage Detector (SVD)
26.1 SVD Module Overview
The S1C17624/604/622/602/621 includes an SVD (supply voltage detector) circuit to monitor the power voltage
supplied to the V pin. It generates an interrupt when the power supply voltage drops below the detection level set
DD
with software. The detection results can also be read via software.
The following shows the features of the SVD module:
• Power supply voltage to be detected: V
• Detection voltage levels:
• Interrupt supported:
Figure 26.1.1 shows the SVD configuration.
V
DD
Divider
HSCLK
OSC1
Clock source
selection
To ITC
26.2 Operating Clock
The SVD module includes a clock source selector, dividers, and a gate circuit for controlling the operation clock.
Clock selection
Use SVDSRC[1:0]/OSC_SVD register to select the clock source from HSCLK (IOSC or OSC3) and OSC1.
Setting SVDSRC to 1 (default) selects OSC1 and setting it to 0 selects HSCLK.
When OSC1 is selected as the clock source, the OSC1 clock (typ. 32.768 kHz) is directly used as SVDCLK.
When HSCLK is selected as the clock source, SVDCLK is generated by dividing HSCLK (IOSC or OSC3
clock) by 512.
Clock enable
The clock supply is enabled with SVDCKEN/OSC_SVD register. The SVDCKEN default setting is 0, which
stops the clock. Setting SVDCKEN to 1 feeds the clock selected to the SVD circuit. If no SVD operation is re-
quired, stop the clock to reduce current consumption.
If SVDCLK is not supplied, the SVD circuit cannot detect voltage levels. However, the SVD control registers
can be accessed even if SVDCLK is stopped.
note: Be sure to set SVDCKEN to 0 before selecting the clock source.
S1C17624/604/622/602/621 TeChniCal Manual
DD
15 levels (1.8 V to 3.2 V)
1 system (power supply voltage drop detection interrupt)
Clock enable
SVDCKEN
1/512
SVDCLK
Gate
SVDSRC
Figure 26.
Seiko epson Corporation
26 SuPPlY VOlTaGe DeTeCTOR (SVD)
SVD enable
Comparison voltage
SVDC[3:0]
Comparison
voltage
setting circuit
Interrupt enable
SVD interrupt request
1.1 SVD Configuration
SVDEN
Detection
Voltage
result
comparator
SVDDT
SVDIE Interrupt
control circuit
SVD
26-1