Svd Operations; Svd Interrupt And Reset; Svd Interrupt - Epson S1C17W22 Technical Manual

10 SUPPLY VOLTAGE DETECTOR (SVD)

10.4.2 SVD Operations

Continuous operation mode
SVD operates in continuous operation mode by default (SVDCTL.SVDMD[1:0] bits = 0x0). In this mode,
SVD operates continuously while the SVDCTL.MODEN bit is set to 1 and it keeps loading the detection re-
sults to the SVDINTF.SVDDT bit. During this period, the current detection results can be obtained by reading
the SVDINTF.SVDDT bit as necessary. Furthermore, an interrupt (if the SVDCTL.SVDRE[3:0] bits ≠ 0xa) or
a reset (if the SVDCTL.SVDRE[3:0] bits = 0xa) can be generated when the SVDINTF.SVDDT bit is set to 1 (low
power supply voltage is detected). This mode can keep detecting power supply voltage drop after the voltage
detection masking time has elapsed even if the IC is placed into SLEEP status or accidental clock stoppage has
occurred.
Intermittent operation mode
SVD operates in intermittent operation mode when the SVDCTL.SVDMD[1:0] bits are set to 0x1 to 0x3. In
this mode, SVD turns on at an interval set using the SVDCTL.SVDMD[1:0] bits to perform detection operation
and then it turns off while the SVDCTL.MODEN bit is set to 1. During this period, the latest detection results
can be obtained by reading the SVDINTF.SVDDT bit as necessary. Furthermore, an interrupt or a reset can be
generated when SVD has successively detected low power supply voltage the number of times specified by the
SVDCTL.SVDSC[1:0] bits.
(1) When the SVDCTL.SVDMD[1:0] bits = 0x0 (continuous operation mode)
SVDCTL.MODEN
SVD operating status
SVDINTF.SVDDT
Low power supply voltage
detection interrupt
(2) When the SVDCTL.SVDMD[1:0] bits ≠ 0x0 (intermittent operation mode)
SVDCTL.MODEN
SVD operating status
SVDINTF.SVDDT
Low power supply voltage
detection interrupt

10.5 SVD Interrupt and Reset

10.5.1 SVD Interrupt

Setting the SVDCTL.SVDRE[3:0] bits to a value other than 0xa allows use of the low power supply voltage detec-
tion interrupt function.
Table 10.5.1.1 Low Power Supply Voltage Detection Interrupt Function
Interrupt Interrupt flag
Low power supply SVDINTF.SVDIF
voltage detection
SVD provides the interrupt enable bit (SVDINTE.SVDIE bit) corresponding to the interrupt flag (SVDINTF.
SVDIF bit). An interrupt request is sent to the interrupt controller only when the SVDINTF.SVDIF bit is set while
the interrupt is enabled by the SVDINTE.SVDIE bit. For more information on interrupt control, refer to the "Interrupt
Controller" chapter.
10-4
V
DD
V
DD
DET
V : Level set using the SVDCTL.SVDC[4:0] bits
SVD
: Voltage detection masking time
DET
: Voltage detection operation
Figure 10.4.2.1 SVD Operations
In continuous operation mode
When the SVDINTF.SVDDT bit is 1
In intermittent operation mode
When low power supply voltage is successively de-
tected the specified number of times
Seiko Epson Corporation
V
SVD
DET
V
SVD
DET
Set condition
S1C17W22/W23 TECHNICAL MANUAL
V
SVD
V
SVD
Clear condition
Writing 1
(Rev. 1.3)