Atmel SAM4S-XPLD Atmel ATSAM4S-XPLD ATSAM4S-XPLD Hoja De Datos

 295

SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

It is possible to generate a waveform (RTCOUT0 and RTCOUT1) in all modes (including backup mode). It can be useful
to control an external sensor and/or tampering function without waking up the processor. Please refer to the RTC section
for waveform generation.

Two separate debouncers are embedded for WKUP0 and WKUP1 inputs.

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.

These inputs can be also used when VDDCORE is powered to get tamper detection function with a low power debounce
function.

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 duty cycle programmable
pulse (i.e. OUT0 = 0x7 in RTC_MR) in order to create the sampling points of both debouncers. The sampling point is the
falling edge of the RTCOUT0 waveform.

 shows an example of an application where two tamper switches are used. RTCOUT0 powers the external

pull-up used by the tampers.

AT91SAM

WKUP0

WKUP1

RTCOUT0

Pull-Up
Resistor

Pull-Up
Resistor

GND

GND

GND