Rohm LAPIS SEMICONDUCTOR ML620Q503, User Manual

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ML620Q503/Q504 User's Manual
Chapter 28 Voltage Level Supervisor
FEUL620Q504 28-8
28.3.1 Supervisor mode
When setting ENVLS with VLSAMD1-0 set to ”10” or ”11”, the supervisor mode is activated.
The supervisor mode is useful for using the low voltage detection interrupt/reset with always-ON. The detection
flag(VLSF)/reset is masked until the ready flag is asserted.
If VLS interrupt is used, set the VLS interrupt before setting ENVLS.
VLSRF (ready flag) is asserted when T16KHZ 4
φ
(+2
φ
when the sampling is enabled) passes after setting
ENVLS. The software should read the VLSF value after VLSRF=”1”.
Even if the VLS interrupt or VLS reset is allowed, the issue is allowed after VLSRF is asserted.
When V
DD
becomes lower than the specified threshold voltage, a VLS interrupt or VLS reset is issued.
To turn off the VLS function, set ENVLS to ”0” from the software.
Figure 28-2 shows an example of the operation timing diagram when detecting without sampling and setting the
VLS reset issue.
①
Set ENVLS to “1” from the CPU to turn on the VLS.
②
When the VLS analog output is stabilized, the ready flag (VLSRF) is set to ”1”.
③
The voltage level detection flag (VLSF) is set to “1” to issue a VLS reset because V
DD
becomes
lower than the specified threshold voltage (V
VLS
).
④
The voltage level detection flag (VLSF) is set to “0” to release the VLS is reset because V
DD
becomes higher than the specified threshold voltage (V
VLS
+H
VLS
).
⑤
Set ENVLS to “0” from the CPU to turn off the VLS.
Figure 28-2 Operation Timing Diagram When Detecting without Sampling and Setting VLS Reset Issue
↓
Stabilization
time
ENVLS
Threshold voltage
V
VLS
VLS analog output
V
SS
V
DD
Ready flag: VLSRF
↓ ↓
↓
↓
Detection flag: VLSF
VLS reset
(rise)
(fall)
V
VLS
+H
VLS
①
② ③
④ ⑤