SAM3SD8B Atmel Corporation, SAM3SD8B Datasheet - Page 284

• Manufacturer Part Number: SAM3SD8B
• Manufacturer: Atmel Corporation

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284
SAM3S8/SD8
SAM3S8/SD8
The WKUP0 and/or WKUP1 inputs can be programmed to perform a wake up of the core power
supply with a debouncing done by RTCOUT0. This can be enabled by setting LPDBC0 bit
and/or LPDBC1 bit in SUPC_WUMR.
In this mode of operation, WKUP0 and/or WKUP1 must not be configured to also act as
debouncing source for the WKUPDBC counter (WKUPEN0 and/or WKUPEN1 must be cleared
in SUPC_WUIR). Refer to
This mode of operation requires the RTC Output (RTCOUT0) to be configured to generate a
square waveform (i.e. OUT0 = 0x1, 0x2, 0x3, 0x4 in RTC_MR) in order to create the sampling
points of both debouncers. The sampling point is the falling edge of the RTCOUT0 waveform.
Figure 16-5
RTCOUTO0 powers the external pullup used by the tampers.
Figure 16-5. Low Power Debouncer (Push-to-Make switch, pull-up resistors)
Figure 16-6. Low Power Debouncer (Push-to-Break switch, pull-down resistors)
shows an example of an application where two tamper switches are used.
GND
Pull-Up
Resistor
GND
Figure
GND
Pull-Down
Resistors
Pull-Up
Resistor
16-5.
GND
RTCOUT0
WKU P1
RTCOUT0
WKU P1
WKU P0
WKU P0
GND
GND
AT91SAM
AT91SAM
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12